11.1 - Master EPA 608 Glossary

Module: Standalone Reference Appendices and Instructor Resources
Purpose: Master lookup glossary for technical, regulatory, service, safety, and examination terminology used throughout the course
Coverage basis: Modules 1–10 of the current project, with regulatory terms cross-checked against current EPA/eCFR sources
Regulatory verification date: August 14, 2026
Important: This glossary summarizes terms for study and field-reference purposes. When exact legal wording controls, the current regulation or official EPA source takes precedence.

Purpose and Use

This glossary is designed to answer a simple question:

I SEE A TERM IN THE COURSE
→ WHAT DOES IT MEAN?
→ WHAT IS IT RELATED TO?
→ WHAT IS IT COMMONLY CONFUSED WITH?
→ WHERE SHOULD I REVIEW IT?

Use Ctrl+F or the editor search function to find a term quickly.

For each entry, the glossary provides:

1. A concise definition.
2. An expanded explanation when additional context is useful.
3. A related term or terms.
4. A commonly confused term when the course identifies a likely confusion.
5. The module or modules in which the term is developed.
6. The EPA 608 examination area or course relevance.
7. Aliases or shorthand when the same concept appears under more than one label.

This glossary intentionally includes both formal regulatory terms and practical HVAC/R terms. A practical field term is not automatically a defined term in federal regulation.

Regulatory-Definition Warning

Some terms in this file have formal meanings in:

• 40 CFR Part 82, Subpart F.
• 40 CFR Part 82, Subpart B.
• 40 CFR Part 84, Subpart C.
• EPA Section 608 guidance and test topics.

When a question or field-compliance decision depends on an exact legal definition:

GLOSSARY SUMMARY
→ IDENTIFY THE CONTROLLING RULE
→ CHECK THE CURRENT OFFICIAL SOURCE

Do not substitute a historical study-guide definition for a current regulatory definition.

Category Coverage

The glossary is arranged alphabetically for fastest lookup. Each entry also identifies a category.

High-Priority Distinctions

The following pairs are repeatedly confused in EPA 608 study and field work.

Alphabetical Glossary

25 mm Hg Absolute

• Category: Type III
• Concise definition: 25 mm Hg absolute is the current Section 608 Table 1 evacuation requirement for low-pressure appliances. It is an absolute-pressure value, not 25 inches Hg vacuum.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: Inches of Mercury Vacuum
• Applicable module(s): 9
• EPA 608 / course relevance: Type III

A

A1

• Category: Safety
• Concise definition: ASHRAE safety group combining lower toxicity Class A with Flammability Class 1, which indicates no flame propagation under the specified test conditions.
• Expanded explanation: The A1 label is a safety classification, not a pressure classification and not a statement that the refrigerant is harmless.
• Related term(s): Toxicity Class A; Flammability Class 1; Safety Group
• Commonly confused with: Pressure class
• Applicable module(s): 6, 10, 11
• EPA 608 / course relevance: Core

A2

• Category: Safety
• Concise definition: ASHRAE safety group combining lower toxicity Class A with Flammability Class 2.
• Expanded explanation: It indicates flame propagation under the applicable classification criteria but is distinct from the 2L low-burning-velocity subclass.
• Related term(s): Toxicity Class A; Flammability Class 2; Safety Group
• Commonly confused with: A2L
• Applicable module(s): 6, 10, 11
• EPA 608 / course relevance: Core

A2L

• Category: Safety
• Concise definition: ASHRAE safety group combining lower toxicity Class A with lower flammability Class 2L and its low-burning-velocity criterion.
• Expanded explanation: A2L refrigerants require attention to refrigerant-specific equipment, ignition control, ventilation, charge limits, codes, and manufacturer instructions.
• Related term(s): Toxicity Class A; Flammability Class 2L; Safety Group
• Commonly confused with: A2; A3; pressure class
• Applicable module(s): 6, 8, 10, 11
• EPA 608 / course relevance: Core; Type II

A3

• Category: Safety
• Concise definition: ASHRAE safety group combining lower toxicity Class A with higher flammability Class 3.
• Expanded explanation: Common hydrocarbon refrigerants can fall in A3 and require strict ignition-source and charge-management controls.
• Related term(s): Toxicity Class A; Flammability Class 3; Safety Group
• Commonly confused with: A2L
• Applicable module(s): 6, 10, 11
• EPA 608 / course relevance: Core

Absolute Pressure

• Category: Pressure, Vacuum, and Measurement
• Concise definition: Absolute pressure is pressure measured relative to a perfect vacuum. It is commonly expressed in psia. The Section 608 pressure-category definitions use absolute pressure.
• Expanded explanation: —
• Related term(s): Gauge Pressure; psia
• Commonly confused with: Gauge Pressure
• Applicable module(s): 4, 5, 8, 9
• EPA 608 / course relevance: Core, Type II, Type III

Acceptable Rise

• Category: General HVAC/R and Service
• Concise definition: Acceptable rise is the maximum pressure increase allowed during a specified isolated vacuum-test period according to the applicable manufacturer or engineering procedure.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 5
• EPA 608 / course relevance: Core

Access Fitting

• Category: Service Tools and Connections
• Concise definition: A device used to create or provide a connection to the refrigerant circuit for service, measurement, recovery, evacuation, or charging.
• Expanded explanation: —
• Related term(s): Temporary Access Fitting
• Commonly confused with: —
• Applicable module(s): 7
• EPA 608 / course relevance: Type I

Access Point

• Category: Service Tools and Connections
• Concise definition: An access point is a service port, service valve, or other approved connection through which the technician can communicate with a refrigerant circuit.
• Expanded explanation: —
• Related term(s): Lowest Access Point
• Commonly confused with: —
• Applicable module(s): 4, 8
• EPA 608 / course relevance: Core, Type II

Accumulator

• Category: Refrigeration Cycle and Thermodynamics
• Concise definition: A suction accumulator is a low-side vessel located between the evaporator and compressor that separates and temporarily stores excess liquid refrigerant so that primarily vapor returns to the compressor.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: Liquid Receiver
• Applicable module(s): 4, 8
• EPA 608 / course relevance: Core, Type II

Acid

• Category: General HVAC/R and Service
• Concise definition: An acid is a corrosive chemical contaminant that can form from refrigerant, lubricant, moisture, heat, and decomposition reactions and can damage system materials.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 3
• EPA 608 / course relevance: Core

Acid Test

• Category: Type II
• Concise definition: An acid test is a service test used to determine whether refrigeration oil/system contamination includes unacceptable acidic products. The test method and interpretation depend on the specific test kit.
• Expanded explanation: —
• Related term(s): Bubble Test
• Commonly confused with: —
• Applicable module(s): 8
• EPA 608 / course relevance: Type II

Active Recall

• Category: Certification, Examination, and Study
• Concise definition: Active recall is the deliberate retrieval of information without looking at the answer or source.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 1
• EPA 608 / course relevance: Core

Active Recovery

• Category: Recovery and Evacuation
• Concise definition: Active recovery is a common study and industry term for recovery using equipment that provides its own refrigerant-moving force. For regulatory questions in this course, use the more precise term self-contained recovery equipment.
• Expanded explanation: —
• Related term(s): Passive Recovery
• Commonly confused with: —
• Applicable module(s): 5
• EPA 608 / course relevance: Core

Adjustment

• Category: General HVAC/R and Service
• Concise definition: An adjustment changes the control measures for substances already covered by the Montreal Protocol through the treaty’s established procedure.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 2
• EPA 608 / course relevance: Core

Administrative Penalty

• Category: Regulatory and Environmental
• Concise definition: An administrative penalty is a monetary penalty pursued through an EPA administrative process under the applicable statutory authority.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 2
• EPA 608 / course relevance: Core

AHRI

• Category: General HVAC/R and Service
• Concise definition: AHRI is the Air-Conditioning, Heating, and Refrigeration Institute. EPA currently recognizes AHRI as an approved organization for certifying Section 608 recovery and recycling equipment. AHRI also publishes technical standards, including Standard 740.
• Expanded explanation: —
• Related term(s): AHRI Standard 700
• Commonly confused with: —
• Applicable module(s): 5
• EPA 608 / course relevance: Core

AHRI Standard 700

• Category: General HVAC/R and Service
• Concise definition: AHRI Standard 700 — Specifications for Refrigerants establishes refrigerant purity specifications and associated test methods.
• Expanded explanation: For the current Section 608 legal definition of reclaim, use the specifications in Appendix A to 40 CFR Part 82, Subpart F, which is based on AHRI Standard 700-2016.
• Related term(s): AHRI Standard 740
• Commonly confused with: —
• Applicable module(s): 5
• EPA 608 / course relevance: Core

AHRI Standard 740

• Category: General HVAC/R and Service
• Concise definition: AHRI Standard 740 establishes performance-test methods for refrigerant recovery and recovery/recycling equipment. Different regulatory appendices incorporate different historical editions.
• Expanded explanation: —
• Related term(s): AHRI Standard 700
• Commonly confused with: —
• Applicable module(s): 5
• EPA 608 / course relevance: Core

AIM Act

• Category: Regulatory and Environmental
• Concise definition: American Innovation and Manufacturing Act of 2020, the federal law establishing a separate framework for phasedown and management of regulated HFCs.
• Expanded explanation: In this course, the AIM Act is kept distinct from Section 608. Current HFC leak-repair requirements discussed in Module 8 are implemented under 40 CFR Part 84, Subpart C rather than § 82.157.
• Related term(s): Regulated Substance; HFC; 40 CFR Part 84
• Commonly confused with: Section 608 ODS leak-repair rule
• Applicable module(s): 8, 10, 11
• EPA 608 / course relevance: Type II; field-compliance reference

Air Infiltration

• Category: Type III
• Concise definition: Air infiltration is the entry of atmospheric air into a refrigeration system through a leak when local system pressure is below atmospheric pressure.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 9
• EPA 608 / course relevance: Type III

Alkylbenzene

• Category: Refrigerants, Blends, and Lubricants
• Concise definition: Alkylbenzene (AB) is a synthetic hydrocarbon refrigeration lubricant commonly associated in EPA 608 study material with R-22 and selected other refrigerant systems.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 3
• EPA 608 / course relevance: Core

Amendment

• Category: Regulatory and Environmental
• Concise definition: An amendment changes the treaty, such as by adding new substances, obligations, or provisions. Ratification requirements apply according to the treaty framework.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 2
• EPA 608 / course relevance: Core

ANSI/ASHRAE Standard 34

• Category: General HVAC/R and Service
• Concise definition: ANSI/ASHRAE Standard 34, Designation and Safety Classification of Refrigerants, establishes the refrigerant designation and safety-classification framework based on toxicity and flammability data.
• Expanded explanation: —
• Related term(s): AHRI Standard 740
• Commonly confused with: —
• Applicable module(s): 6
• EPA 608 / course relevance: Core

Appliance

• Category: General HVAC/R and Service
• Concise definition: A device that contains and uses a class I substance, class II substance, or substitute as a refrigerant for household or commercial purposes; for a multiple-circuit system, each independent circuit is treated as a separate appliance.
• Expanded explanation: The regulatory definition includes air conditioners, MVACs, refrigerators, chillers, freezers, and other covered equipment.
• Related term(s): Small Appliance
• Commonly confused with: —
• Applicable module(s): 1
• EPA 608 / course relevance: Core

Appliance Compressor

• Category: Refrigeration Cycle and Thermodynamics
• Concise definition: The appliance compressor is the compressor that is part of the refrigeration or air-conditioning appliance itself. When this compressor is required to move refrigerant during recovery, the recovery arrangement is system-dependent.
• Expanded explanation: —
• Related term(s): Compressor
• Commonly confused with: —
• Applicable module(s): 5
• EPA 608 / course relevance: Core

Appliance Full Charge

• Category: Type II
• Concise definition: Full charge is the amount of refrigerant required for normal operation of an appliance as determined using the applicable regulatory method. Full charge is used in leak-rate calculations and applicability determinations.
• Expanded explanation: —
• Related term(s): Full-Charge Threshold
• Commonly confused with: —
• Applicable module(s): 8
• EPA 608 / course relevance: Type II

Appliance Owner

• Category: Type I
• Concise definition: The person or entity owning the small appliance before service or disposal. The owner should arrange lawful handling but is not automatically the person assigned every final-processor recordkeeping obligation.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 7
• EPA 608 / course relevance: Type I

Appliance Receiver

• Category: Refrigeration Cycle and Thermodynamics
• Concise definition: An appliance receiver is a high-side vessel that stores/manages liquid refrigerant, typically downstream of the condenser.
• Expanded explanation: —
• Related term(s): Receiver
• Commonly confused with: —
• Applicable module(s): 8
• EPA 608 / course relevance: Type II

Apprentice

• Category: Certification, Examination, and Study
• Concise definition: A person currently registered in appliance maintenance, service, repair, or disposal with the U.S. Department of Labor Office of Apprenticeship or a recognized State Apprenticeship Council.
• Expanded explanation: Under the current Section 608 definition, apprentice status is limited to two years from first registration and covered work requires the applicable supervision conditions.
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 1
• EPA 608 / course relevance: Core

Approved Certifying Organization

• Category: Certification, Examination, and Study
• Concise definition: An approved certifying organization is an organization authorized by EPA to administer the Section 608 technician-certification test and issue certification credentials.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 1
• EPA 608 / course relevance: Core

Approved Equipment Testing Organization

• Category: General HVAC/R and Service
• Concise definition: An approved equipment testing organization is an organization that has received EPA approval to certify recovery and recycling equipment under the applicable Section 608 standards.
• Expanded explanation: —
• Related term(s): Dedicated Equipment
• Commonly confused with: —
• Applicable module(s): 5
• EPA 608 / course relevance: Core

ARI

• Category: General HVAC/R and Service
• Concise definition: Air-Conditioning and Refrigeration Institute, the historical organization name appearing in older refrigerant recovery-equipment standards.
• Expanded explanation: The organization is now AHRI. Older regulations and equipment references may still cite ARI Standard 740 editions by their historical name.
• Related term(s): AHRI; AHRI Standard 740
• Commonly confused with: AHRI
• Applicable module(s): 5, 10, 11
• EPA 608 / course relevance: Core

ASHRAE

• Category: Safety
• Concise definition: American Society of Heating, Refrigerating and Air-Conditioning Engineers.
• Expanded explanation: ASHRAE standards used in this course include refrigerant designation and safety-classification concepts, particularly ANSI/ASHRAE Standard 34.
• Related term(s): ANSI/ASHRAE Standard 34; Safety Group
• Commonly confused with: AHRI
• Applicable module(s): 3, 6, 10, 11
• EPA 608 / course relevance: Core

Asphyxiation

• Category: Safety
• Concise definition: Loss of adequate oxygen supply to the body. A large refrigerant release can contribute to asphyxiation by displacing normal air.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 6
• EPA 608 / course relevance: Core

Atmospheric Pressure

• Category: Pressure, Vacuum, and Measurement
• Concise definition: Atmospheric pressure is the pressure exerted by the surrounding atmosphere. Near sea level under standard reference conditions, it is approximately $14.7\text{psia}$, although actual local atmospheric pressure varies with elevation and weather.
• Expanded explanation: —
• Related term(s): Subatmospheric Pressure
• Commonly confused with: —
• Applicable module(s): 4, 9
• EPA 608 / course relevance: Core, Type III

Audit Trail

• Category: Leak Repair and Recordkeeping
• Concise definition: An audit trail is a record showing who created or changed information, what changed, and when the action occurred.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 2
• EPA 608 / course relevance: Core

Authority Having Jurisdiction (AHJ)

• Category: Regulatory and Environmental
• Concise definition: The organization, office, or individual responsible for approving equipment, installations, procedures, or compliance with the applicable code.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 6
• EPA 608 / course relevance: Core

Authorized Packaging

• Category: Disposal, Cylinders, and Shipping
• Concise definition: A package or pressure receptacle permitted by the applicable Hazardous Materials Regulations for the material and transportation conditions.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 6
• EPA 608 / course relevance: Core

Authorized Representative

• Category: Regulatory and Environmental
• Concise definition: An authorized representative is a person permitted to purchase or receive refrigerant on behalf of a qualifying buyer.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 2
• EPA 608 / course relevance: Core

Auxiliary Heat-Exchange Coil

• Category: Refrigeration Cycle and Thermodynamics
• Concise definition: An auxiliary heat-exchange coil is a refrigerant-containing auxiliary heat exchanger recognized in the current Section 608 major-repair definition. Removing it constitutes major maintenance, service, or repair.
• Expanded explanation: —
• Related term(s): Heat
• Commonly confused with: —
• Applicable module(s): 8
• EPA 608 / course relevance: Type II

Available Cylinder Capacity

• Category: Disposal, Cylinders, and Shipping
• Concise definition: Available cylinder capacity is the remaining amount of refrigerant that can be safely added to a recovery cylinder without exceeding its allowable fill limit. It is determined by weight, not by cylinder pressure.
• Expanded explanation: —
• Related term(s): Recovery Cylinder
• Commonly confused with: —
• Applicable module(s): 5, 8
• EPA 608 / course relevance: Core, Type II

Azeotrope

• Category: Refrigerants, Blends, and Lubricants
• Concise definition: An azeotrope is a refrigerant blend that, at its azeotropic composition, behaves essentially like a single substance during liquid-vapor phase change and has essentially no temperature glide at constant pressure.
• Expanded explanation: —
• Related term(s): Zeotrope
• Commonly confused with: Zeotrope
• Applicable module(s): 3
• EPA 608 / course relevance: Core

B

B1

• Category: Safety
• Concise definition: ASHRAE safety group combining higher toxicity Class B with Flammability Class 1.
• Expanded explanation: The B toxicity designation and the numerical flammability designation describe different hazard dimensions.
• Related term(s): Toxicity Class B; Flammability Class 1; Safety Group
• Commonly confused with: A1
• Applicable module(s): 6, 10, 11
• EPA 608 / course relevance: Core

B2

• Category: Safety
• Concise definition: ASHRAE safety group combining higher toxicity Class B with Flammability Class 2.
• Expanded explanation: The safety group must be interpreted using both the toxicity letter and the flammability number.
• Related term(s): Toxicity Class B; Flammability Class 2; Safety Group
• Commonly confused with: B2L
• Applicable module(s): 6, 11
• EPA 608 / course relevance: Core

B2L

• Category: Safety
• Concise definition: ASHRAE safety group combining higher toxicity Class B with lower flammability Class 2L.
• Expanded explanation: Ammonia is a common example discussed in HVAC/R safety contexts; its toxicity and flammability both require consideration.
• Related term(s): Toxicity Class B; Flammability Class 2L; Safety Group
• Commonly confused with: A2L
• Applicable module(s): 6, 10, 11
• EPA 608 / course relevance: Core

B3

• Category: Safety
• Concise definition: ASHRAE safety group combining higher toxicity Class B with higher flammability Class 3.
• Expanded explanation: This combination represents both higher-toxicity and higher-flammability classifications and requires refrigerant-specific safety controls.
• Related term(s): Toxicity Class B; Flammability Class 3; Safety Group
• Commonly confused with: A3
• Applicable module(s): 6, 11
• EPA 608 / course relevance: Core

Back Pressure

• Category: Pressure, Vacuum, and Measurement
• Concise definition: Back pressure is the pressure opposing the recovery-machine discharge. Higher recovery-cylinder pressure increases recovery-machine back pressure.
• Expanded explanation: —
• Related term(s): Head Pressure
• Commonly confused with: —
• Applicable module(s): 5
• EPA 608 / course relevance: Core

Barometer

• Category: Pressure, Vacuum, and Measurement
• Concise definition: A barometer is an instrument used to measure atmospheric pressure.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 4
• EPA 608 / course relevance: Core

Blend

• Category: Refrigerants, Blends, and Lubricants
• Concise definition: A blend is a refrigerant composed of two or more components in specified proportions.
• Expanded explanation: —
• Related term(s): Near-Azeotropic Blend
• Commonly confused with: Pure Refrigerant
• Applicable module(s): 3
• EPA 608 / course relevance: Core

Boundary Case

• Category: Type I
• Concise definition: An equipment-classification situation in which the correct EPA 608 category is not obvious from appearance alone and requires application of the formal definition or overlap rules.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 7
• EPA 608 / course relevance: Type I

Bubble Point

• Category: Refrigerants, Blends, and Lubricants
• Concise definition: The bubble point is the saturated-liquid temperature of a zeotropic blend at a specified pressure. When heating saturated liquid, the first vapor begins to form at this boundary.
• Expanded explanation: —
• Related term(s): Dew Point
• Commonly confused with: Dew Point
• Applicable module(s): 3, 4
• EPA 608 / course relevance: Core

Bubble Test

• Category: Type II
• Concise definition: A leak-location method in which a liquid leak-detection solution is applied to a pressurized suspected leak point and escaping gas forms visible bubbles.
• Expanded explanation: —
• Related term(s): Acid Test
• Commonly confused with: —
• Applicable module(s): 6, 8
• EPA 608 / course relevance: Core, Type II

Bulk Liquid Recovery

• Category: Recovery and Evacuation
• Concise definition: Bulk liquid recovery is the early stage of refrigerant recovery in which accessible liquid refrigerant is removed before the remaining vapor. It generally removes refrigerant mass much faster than vapor-only recovery.
• Expanded explanation: —
• Related term(s): Liquid Recovery
• Commonly confused with: —
• Applicable module(s): 5, 8, 9
• EPA 608 / course relevance: Core, Type II, Type III

Burning Velocity

• Category: Safety
• Concise definition: The speed at which a flame front propagates through a combustible refrigerant-air mixture under the specified test conditions. Burning velocity is one of the properties used to distinguish Class 2L from other flammable classifications.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 6
• EPA 608 / course relevance: Core

C

CAA

• Category: Regulatory and Environmental
• Concise definition: Clean Air Act, the federal statute that contains Section 608 and other air-pollution-control provisions.
• Expanded explanation: Section 608 refrigerant-management requirements are implemented under the Clean Air Act through federal regulations including 40 CFR Part 82.
• Related term(s): Clean Air Act; Title VI
• Commonly confused with: EPA regulation versus the statute itself
• Applicable module(s): 1, 2, 10, 11
• EPA 608 / course relevance: Core

Carbon Dioxide Equivalent

• Category: Regulatory and Environmental
• Concise definition: Carbon dioxide equivalent, written as $C{O}_{2}e$, expresses a greenhouse-gas mass as the mass of carbon dioxide having the same specified GWP-based effect. $$C{O}_{2}e=m_{\mathrm{gas}}\cdot \mathrm{GWP}$$
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 2
• EPA 608 / course relevance: Core

Cardiac Sensitization

• Category: Safety
• Concise definition: An increased sensitivity of the heart to catecholamines associated with sufficiently high exposure to certain chemicals, including some halocarbon refrigerants. The effect can increase the risk of abnormal heart rhythms.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 6
• EPA 608 / course relevance: Core

Catalyst

• Category: Regulatory and Environmental
• Concise definition: A catalyst participates in a chemical reaction sequence and is regenerated rather than consumed in the overall net reaction.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 2
• EPA 608 / course relevance: Core

Catalytic Cycle

• Category: Regulatory and Environmental
• Concise definition: A catalytic cycle is a sequence of reactions in which a reactive substance is regenerated and can repeat the sequence.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 2
• EPA 608 / course relevance: Core

Center Service Port

• Category: Service Tools and Connections
• Concise definition: The center service port is the common manifold connection used to connect an external service device such as a refrigerant source, recovery machine, or vacuum pump.
• Expanded explanation: —
• Related term(s): Service Port
• Commonly confused with: —
• Applicable module(s): 4
• EPA 608 / course relevance: Core

Centrifugal Chiller

• Category: Type III
• Concise definition: A centrifugal chiller is a vapor-compression liquid chiller that uses a dynamic centrifugal compressor to raise refrigerant-vapor pressure. Low-pressure centrifugal chillers are the principal Type III equipment example in EPA examination preparation.
• Expanded explanation: —
• Related term(s): Type III Certification; Purge Unit
• Commonly confused with: —
• Applicable module(s): 9
• EPA 608 / course relevance: Type III

Centrifugal Compressor

• Category: Refrigeration Cycle and Thermodynamics
• Concise definition: A centrifugal compressor is a dynamic compressor that uses a rotating impeller to add velocity and energy to vapor and a diffuser or associated flow path to convert part of that energy into increased static pressure.
• Expanded explanation: —
• Related term(s): Compressor
• Commonly confused with: —
• Applicable module(s): 9
• EPA 608 / course relevance: Type III

Certification Misuse

• Category: Certification, Examination, and Study
• Concise definition: Certification misuse is unauthorized, deceptive, or out-of-scope use of a technician credential.
• Expanded explanation: —
• Related term(s): Limited Certification
• Commonly confused with: —
• Applicable module(s): 2
• EPA 608 / course relevance: Core

Certified Refrigerant Recovery or Recycling Equipment

• Category: Recovery and Evacuation
• Concise definition: Certified refrigerant recovery or recycling equipment is equipment that satisfies the applicable certification pathway under 40 CFR Part 82, Subpart F. The exact pathway depends partly on equipment type and manufacture or import date.
• Expanded explanation: —
• Related term(s): Dedicated Recovery Equipment
• Commonly confused with: —
• Applicable module(s): 5
• EPA 608 / course relevance: Core

CFC

• Category: Refrigerants, Blends, and Lubricants
• Concise definition: Chlorofluorocarbon; a refrigerant family containing chlorine, fluorine, and carbon.
• Expanded explanation: CFCs are ozone-depleting substances with nonzero ODP and are associated with historical refrigerants such as R-11 and R-12.
• Related term(s): Chlorofluorocarbon; Ozone-Depleting Substance
• Commonly confused with: HCFC; HFC
• Applicable module(s): 2, 3, 10, 11
• EPA 608 / course relevance: Core

Charging Valve

• Category: Service Tools and Connections
• Concise definition: A charging valve is a designated refrigerant service connection used to introduce refrigerant according to the equipment manufacturer’s charging procedure. Type III exam preparation emphasizes the evaporator charging valve on centrifugal chillers.
• Expanded explanation: —
• Related term(s): Evaporator Charging Valve
• Commonly confused with: —
• Applicable module(s): 9
• EPA 608 / course relevance: Type III

Chemical Stability

• Category: General HVAC/R and Service
• Concise definition: Chemical stability is the ability of a lubricant to resist harmful chemical breakdown during service.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 3
• EPA 608 / course relevance: Core

Chemical-Splash Goggles

• Category: Safety
• Concise definition: Eye protection designed to provide more complete coverage against liquid or chemical splash than ordinary spectacles.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 6
• EPA 608 / course relevance: Core

Chlorine Monoxide

• Category: Regulatory and Environmental
• Concise definition: Chlorine monoxide, written as ${\mathrm{ClO}}^{\bullet }$ in its reactive radical form, is produced when a chlorine atom reacts with ozone.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 2
• EPA 608 / course relevance: Core

Chlorofluorocarbon

• Category: Refrigerants, Blends, and Lubricants
• Concise definition: A chlorofluorocarbon, or CFC, is a compound containing chlorine, fluorine, and carbon. Many CFCs are long-lived ozone-depleting substances.
• Expanded explanation: —
• Related term(s): Hydrochlorofluorocarbon; Ozone-Depleting Substance
• Commonly confused with: —
• Applicable module(s): 2
• EPA 608 / course relevance: Core

Chronic Leaker

• Category: Leak Repair and Recordkeeping
• Concise definition: For the current Section 608 and AIM Act reporting provisions discussed here, a chronically leaking appliance is a covered appliance that leaks 125% or more of its full charge in a calendar year, triggering the applicable EPA reporting requirement.
• Expanded explanation: —
• Related term(s): Electronic Leak Detector
• Commonly confused with: —
• Applicable module(s): 8
• EPA 608 / course relevance: Type II

Civil Judicial Action

• Category: General HVAC/R and Service
• Concise definition: A civil judicial action is a case filed in federal court seeking penalties, injunctions, or other relief.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 2
• EPA 608 / course relevance: Core

Class I Substance

• Category: Refrigerants, Blends, and Lubricants
• Concise definition: An ozone-depleting substance listed in 40 CFR Part 82, Subpart A, Appendix A.
• Expanded explanation: CFCs and halons are major examples discussed in this course.
• Related term(s): Class II Substance
• Commonly confused with: Class II Substance
• Applicable module(s): 2
• EPA 608 / course relevance: Core

Class II Substance

• Category: Refrigerants, Blends, and Lubricants
• Concise definition: An ozone-depleting substance listed in 40 CFR Part 82, Subpart A, Appendix B.
• Expanded explanation: HCFCs are the principal Class II family discussed in this course.
• Related term(s): Class I Substance
• Commonly confused with: Class I Substance
• Applicable module(s): 2
• EPA 608 / course relevance: Core

Clean Air Act

• Category: Regulatory and Environmental
• Concise definition: The Clean Air Act is the federal law under which EPA administers Section 608 refrigerant-management requirements.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 1
• EPA 608 / course relevance: Core

Close and Continuous Supervision

• Category: General HVAC/R and Service
• Concise definition: Close and continuous supervision means that the properly certified supervising technician remains able to direct, observe, and correct the apprentice’s work throughout the covered activity.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 1
• EPA 608 / course relevance: Core

Closed-Book Examination

• Category: Certification, Examination, and Study
• Concise definition: A closed-book examination prohibits use of unauthorized notes, books, internet resources, or outside assistance.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 1
• EPA 608 / course relevance: Core

Combustible Mixture

• Category: Safety
• Concise definition: A gas or vapor mixture capable of burning under specified conditions. For refrigeration service, some refrigerant-air mixtures can become combustible under conditions different from the standard classification condition.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 6
• EPA 608 / course relevance: Core

Comfort Cooling

• Category: Type II
• Concise definition: Air-conditioning appliances used to control heat and/or humidity in occupied facilities such as residential, office, and commercial buildings.
• Expanded explanation: The term describes end use and does not by itself determine Type I, Type II, or Type III certification.
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 8
• EPA 608 / course relevance: Type II

Commercial Refrigeration

• Category: Type II
• Concise definition: Refrigeration appliances used in retail food and cold-storage warehouse sectors.
• Expanded explanation: Examples include supermarket, convenience-store, restaurant, food-service, and cold-storage equipment.
• Related term(s): Industrial-Process Refrigeration
• Commonly confused with: —
• Applicable module(s): 8
• EPA 608 / course relevance: Type II

Compliance Order

• Category: Regulatory and Environmental
• Concise definition: A compliance order directs a regulated person or organization to correct or stop violations.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 2
• EPA 608 / course relevance: Core

Compound Gauge

• Category: Service Tools and Connections
• Concise definition: A compound gauge measures positive low-side gauge pressure and also indicates vacuum below atmospheric pressure.
• Expanded explanation: —
• Related term(s): Micron Gauge
• Commonly confused with: —
• Applicable module(s): 4
• EPA 608 / course relevance: Core

Compressed Air

• Category: Safety
• Concise definition: Atmospheric air raised to a pressure above ambient pressure. Compressed air contains oxygen and must not be used as the pressure-test gas for a refrigerant circuit.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 6
• EPA 608 / course relevance: Core

Compressor

• Category: Refrigeration Cycle and Thermodynamics
• Concise definition: A compressor is a mechanical device that draws in refrigerant vapor, compresses it to a higher pressure, and drives refrigerant circulation through the vapor-compression system.
• Expanded explanation: —
• Related term(s): Discharge Line; Suction Line
• Commonly confused with: —
• Applicable module(s): 4, 8
• EPA 608 / course relevance: Core, Type II

Compressor Burnout

• Category: Refrigeration Cycle and Thermodynamics
• Concise definition: A compressor burnout is severe electrical/motor failure that can thermally and chemically contaminate the refrigerant circuit with damaged oil, acid, carbon, moisture, and debris.
• Expanded explanation: —
• Related term(s): Compressor
• Commonly confused with: —
• Applicable module(s): 8
• EPA 608 / course relevance: Type II

Compressor Replacement

• Category: Refrigeration Cycle and Thermodynamics
• Concise definition: A major service action requiring removal of the appliance compressor and opening of the refrigerant circuit. For a Type I small appliance, required recovery must be completed before the circuit is opened.
• Expanded explanation: —
• Related term(s): Compressor
• Commonly confused with: —
• Applicable module(s): 7
• EPA 608 / course relevance: Type I

Condensation

• Category: Refrigeration Cycle and Thermodynamics
• Concise definition: Condensation is the phase change from vapor to liquid. During refrigeration-system condensation, refrigerant rejects heat.
• Expanded explanation: —
• Related term(s): Condenser
• Commonly confused with: —
• Applicable module(s): 3, 4
• EPA 608 / course relevance: Core

Condenser

• Category: Refrigeration Cycle and Thermodynamics
• Concise definition: The condenser is the refrigerant heat exchanger where higher-pressure refrigerant rejects heat and condenses while condenser water carries the rejected heat away.
• Expanded explanation: —
• Related term(s): Heat Rejection; Liquid Line
• Commonly confused with: —
• Applicable module(s): 4, 8, 9
• EPA 608 / course relevance: Core, Type II, Type III

Condenser Head Pressure

• Category: Refrigeration Cycle and Thermodynamics
• Concise definition: Condenser head pressure is the higher refrigerant-side pressure associated with the condenser/compressor discharge region. Noncondensable gases can add to the measured pressure and increase the required compressor pressure rise.
• Expanded explanation: —
• Related term(s): Condenser
• Commonly confused with: —
• Applicable module(s): 9
• EPA 608 / course relevance: Type III

Condenser Water Box

• Category: Refrigeration Cycle and Thermodynamics
• Concise definition: A condenser water box directs condenser water into or out of the condenser tube bundle.
• Expanded explanation: —
• Related term(s): Evaporator Water Box
• Commonly confused with: —
• Applicable module(s): 9
• EPA 608 / course relevance: Type III

Conductance

• Category: Pressure, Vacuum, and Measurement
• Concise definition: Conductance describes how easily gas can flow through an evacuation path. Shorter, larger-diameter, less restrictive paths have higher conductance.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 5
• EPA 608 / course relevance: Core

Confidence Code

• Category: Certification, Examination, and Study
• Concise definition: A confidence code records how certain the student was and whether the answer was supported by reliable reasoning.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 1
• EPA 608 / course relevance: Core

Confined Space

• Category: Safety
• Concise definition: Under OSHA general-industry terminology, a space that: Can be bodily entered for work. Has limited or restricted entry or exit. Is not designed for continuous employee occupancy.
• Expanded explanation: —
• Related term(s): Permit-Required Confined Space
• Commonly confused with: —
• Applicable module(s): 6
• EPA 608 / course relevance: Core

Consideration

• Category: General HVAC/R and Service
• Concise definition: Consideration means payment, barter, or another form of compensation for servicing or repairing an MVAC.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 1
• EPA 608 / course relevance: Core

Consumption

• Category: Regulatory and Environmental
• Concise definition: Under the Montreal Protocol, consumption is production plus imports minus exports of controlled substances. It is not simply the amount of refrigerant operating inside equipment.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 2
• EPA 608 / course relevance: Core

Contaminated Oil

• Category: Type II
• Concise definition: Contaminated oil is refrigeration lubricant containing undesirable moisture, acid, carbon, metal particles, decomposition products, incorrect lubricant, or other foreign material.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 8
• EPA 608 / course relevance: Type II

Controlled Hot-Water Pressurization

• Category: Type III
• Concise definition: Controlled hot-water pressurization uses warm/hot water circulated through an appropriate chiller heat exchanger to raise refrigerant temperature and pressure in a controlled manner without intentionally introducing a noncondensable gas.
• Expanded explanation: —
• Related term(s): Water Circulation
• Commonly confused with: —
• Applicable module(s): 9
• EPA 608 / course relevance: Type III

Copper Plating

• Category: Safety
• Concise definition: Copper plating is the unintended deposition of copper onto compressor or other metal surfaces as part of a contamination/corrosion process.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 3
• EPA 608 / course relevance: Core

Core

• Category: Certification, Examination, and Study
• Concise definition: Core is the common examination section covering environmental effects, refrigerant regulations, recovery concepts, safety, cylinders, and other knowledge used across Types I, II, and III. Core alone is not an equipment certification.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: Universal Certification
• Applicable module(s): 1
• EPA 608 / course relevance: Core

Covered Refrigerant

• Category: Refrigerants, Blends, and Lubricants
• Concise definition: A covered refrigerant is a Class I, Class II, or non-exempt substitute refrigerant subject to the sales restriction.
• Expanded explanation: —
• Related term(s): Refrigerant
• Commonly confused with: —
• Applicable module(s): 2
• EPA 608 / course relevance: Core

Crankcase Heater

• Category: Refrigeration Cycle and Thermodynamics
• Concise definition: A crankcase heater is a heater used to maintain compressor crankcase/oil temperature during off cycles to reduce refrigerant migration and refrigerant dilution of the oil.
• Expanded explanation: —
• Related term(s): Defrost Heater
• Commonly confused with: —
• Applicable module(s): 8
• EPA 608 / course relevance: Type II

Credential

• Category: Certification, Examination, and Study
• Concise definition: A credential is the certificate, card, certification number, or other record showing successful Section 608 certification.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 1
• EPA 608 / course relevance: Core

Critical Temperature

• Category: Pressure, Vacuum, and Measurement
• Concise definition: The critical temperature is the highest temperature at which a substance can exist as a distinct liquid-vapor equilibrium. Above the critical temperature, pressure alone cannot condense the substance into an ordinary liquid phase.
• Expanded explanation: The current very-high-pressure appliance definition includes refrigerants with a critical temperature below $104^{\circ }\text{F}$.
• Related term(s): Pressure-Temperature Chart
• Commonly confused with: —
• Applicable module(s): 8
• EPA 608 / course relevance: Type II

Cross-Contamination

• Category: General HVAC/R and Service
• Concise definition: Cross-contamination occurs when one refrigerant, lubricant, debris, moisture, or other unwanted material contaminates another refrigerant stream or piece of service equipment.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 3, 5, 7, 8
• EPA 608 / course relevance: Core, Type I, Type II

Current Rule

• Category: Regulatory and Environmental
• Concise definition: A current rule is a requirement in effect on the stated verification date.
• Expanded explanation: —
• Related term(s): Scheduled Rule
• Commonly confused with: Historical Rule
• Applicable module(s): 2
• EPA 608 / course relevance: Core

Cylinder Back Pressure

• Category: Disposal, Cylinders, and Shipping
• Concise definition: Cylinder back pressure is the receiving pressure that the recovery machine must overcome at its discharge. A hotter recovery cylinder generally has higher pressure and greater back pressure.
• Expanded explanation: —
• Related term(s): Cylinder-Pressure Gauge
• Commonly confused with: —
• Applicable module(s): 8
• EPA 608 / course relevance: Type II

Cylinder Label

• Category: Disposal, Cylinders, and Shipping
• Concise definition: A cylinder label identifies the refrigerant or material assigned to the cylinder and provides information needed for safe handling. It is a primary identification source and is more reliable than color alone.
• Expanded explanation: —
• Related term(s): Recovery Cylinder
• Commonly confused with: —
• Applicable module(s): 3
• EPA 608 / course relevance: Core

Cylinder-Pressure Gauge

• Category: Disposal, Cylinders, and Shipping
• Concise definition: A regulator gauge that indicates pressure on the cylinder/high-pressure side.
• Expanded explanation: —
• Related term(s): Cylinder Back Pressure
• Commonly confused with: —
• Applicable module(s): 6
• EPA 608 / course relevance: Core

D

De Minimis Release

• Category: Regulatory and Environmental
• Concise definition: A de minimis release is a limited incidental release associated with a good-faith attempt to recover, recycle, or safely dispose of refrigerant while complying with the applicable practices.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: Vent
• Applicable module(s): 2
• EPA 608 / course relevance: Core

Decay Test

• Category: Recovery and Evacuation
• Concise definition: A decay test is another name for a standing vacuum test in which the vacuum pump is isolated and the change in absolute pressure is observed over time.
• Expanded explanation: —
• Related term(s): Vacuum-Decay Test
• Commonly confused with: —
• Applicable module(s): 5
• EPA 608 / course relevance: Core

Decomposition Product

• Category: Safety
• Concise definition: A new chemical substance formed when a chemical breaks down because of heat, reaction, radiation, or another mechanism.
• Expanded explanation: —
• Related term(s): Thermal Decomposition
• Commonly confused with: —
• Applicable module(s): 6
• EPA 608 / course relevance: Core

Dedicated Equipment

• Category: General HVAC/R and Service
• Concise definition: Dedicated equipment is service or recovery equipment reserved for a specific refrigerant or defined application to reduce contamination risk.
• Expanded explanation: —
• Related term(s): Dedicated Recovery Equipment; Cross-Contamination
• Commonly confused with: —
• Applicable module(s): 3
• EPA 608 / course relevance: Core

Dedicated Recovery Equipment

• Category: Recovery and Evacuation
• Concise definition: Dedicated recovery equipment is equipment assigned to a specific refrigerant, refrigerant family, safety class, or contamination stream to reduce cross-contamination and meet applicable manufacturer or service requirements.
• Expanded explanation: —
• Related term(s): Recovery Equipment Certification
• Commonly confused with: —
• Applicable module(s): 8
• EPA 608 / course relevance: Type II

Deep Evacuation

• Category: Recovery and Evacuation
• Concise definition: Deep evacuation is the process of reducing a sealed refrigeration system to a low absolute pressure to remove air, noncondensables, and water vapor before charging.
• Expanded explanation: —
• Related term(s): Evacuation
• Commonly confused with: —
• Applicable module(s): 3
• EPA 608 / course relevance: Core

Deep Vacuum

• Category: Recovery and Evacuation
• Concise definition: A condition in which system absolute pressure is substantially below atmospheric pressure. The exact regulatory low-pressure recovery endpoint is covered in Section 9.9.
• Expanded explanation: —
• Related term(s): Vacuum
• Commonly confused with: —
• Applicable module(s): 5, 9
• EPA 608 / course relevance: Core, Type III

Defrost Heater

• Category: Refrigeration Cycle and Thermodynamics
• Concise definition: An electrical heater used by certain refrigeration appliances to melt frost from the evaporator. When allowed by the appliance procedure, it can also supply controlled heat that helps trapped refrigerant vaporize during recovery.
• Expanded explanation: —
• Related term(s): Oil Heater
• Commonly confused with: —
• Applicable module(s): 7
• EPA 608 / course relevance: Type I

Dehydration

• Category: Recovery and Evacuation
• Concise definition: Dehydration is removal of moisture from the refrigeration system. Under vacuum, water is encouraged to vaporize so the vacuum pump can remove the vapor.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: Recovery Endpoint
• Applicable module(s): 5
• EPA 608 / course relevance: Core

Delivery-Pressure Gauge

• Category: Service Tools and Connections
• Concise definition: A regulator gauge that indicates controlled pressure on the downstream side.
• Expanded explanation: —
• Related term(s): Gauge Pressure
• Commonly confused with: —
• Applicable module(s): 6
• EPA 608 / course relevance: Core

Desiccant

• Category: General HVAC/R and Service
• Concise definition: A desiccant is a material used in a filter-drier to absorb or adsorb moisture from the refrigerant circuit, depending on the desiccant type and design.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 3, 4
• EPA 608 / course relevance: Core

Desorption / Refrigerant Release From Oil

• Category: Refrigerants, Blends, and Lubricants
• Concise definition: Desorption in this teaching context refers to refrigerant leaving the oil solution and entering the refrigerant vapor space as temperature and pressure conditions change.
• Expanded explanation: —
• Related term(s): Virgin Refrigerant
• Commonly confused with: —
• Applicable module(s): 9
• EPA 608 / course relevance: Type III

Desuperheating

• Category: Refrigeration Cycle and Thermodynamics
• Concise definition: Desuperheating is sensible cooling of superheated vapor until it reaches the saturated-vapor condition.
• Expanded explanation: —
• Related term(s): Superheat
• Commonly confused with: —
• Applicable module(s): 4
• EPA 608 / course relevance: Core

Dew Point

• Category: Refrigerants, Blends, and Lubricants
• Concise definition: The dew point is the saturated-vapor temperature of a zeotropic blend at a specified pressure. When cooling saturated vapor, the first liquid begins to form at this boundary.
• Expanded explanation: —
• Related term(s): Bubble Point
• Commonly confused with: Bubble Point
• Applicable module(s): 3, 4
• EPA 608 / course relevance: Core

Diagnostic Test

• Category: Certification, Examination, and Study
• Concise definition: A diagnostic test is an assessment used to identify strengths, weaknesses, and study priorities.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 1
• EPA 608 / course relevance: Core

Dielectric Strength

• Category: General HVAC/R and Service
• Concise definition: Dielectric strength is the ability of an insulating material to resist electrical breakdown under an applied electric field.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 3
• EPA 608 / course relevance: Core

Discharge Line

• Category: Refrigeration Cycle and Thermodynamics
• Concise definition: The discharge line carries high-pressure high-temperature vapor from the compressor outlet to the condenser inlet.
• Expanded explanation: —
• Related term(s): Discharge Pressure
• Commonly confused with: —
• Applicable module(s): 4, 8
• EPA 608 / course relevance: Core, Type II

Discharge Pressure

• Category: Refrigeration Cycle and Thermodynamics
• Concise definition: Discharge pressure is the pressure at the outlet side of the recovery machine as it pushes refrigerant toward the recovery cylinder.
• Expanded explanation: —
• Related term(s): Discharge Line
• Commonly confused with: —
• Applicable module(s): 5, 7
• EPA 608 / course relevance: Core, Type I

Discharge Service Valve

• Category: Service Tools and Connections
• Concise definition: A discharge service valve is a service valve at or near the compressor discharge connection used for isolation and service access. A reciprocating compressor must not be operated with its required discharge path closed.
• Expanded explanation: —
• Related term(s): Service Valve
• Commonly confused with: —
• Applicable module(s): 8
• EPA 608 / course relevance: Type II

Disposable Refrigerant Cylinder

• Category: Disposal, Cylinders, and Shipping
• Concise definition: A nonrefillable cylinder used to supply refrigerant. It is not a refillable recovery cylinder and is not itself a refrigeration appliance.
• Expanded explanation: —
• Related term(s): Recovery Cylinder
• Commonly confused with: Recovery Cylinder
• Applicable module(s): 6
• EPA 608 / course relevance: Core

Disposal

• Category: Type I
• Concise definition: Disposal includes processes leading to discarding, dismantling, scrapping, recycling, or otherwise rendering an appliance unusable. The regulatory definition includes several ways in which an appliance or its parts may be discarded or disassembled.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 1, 6, 7
• EPA 608 / course relevance: Core, Type I

Disposal Chain

• Category: Disposal, Cylinders, and Shipping
• Concise definition: The sequence of persons/entities through which an end-of-life appliance passes. It may include: Owner. Collector. Recovery person. Transporter. Scrap processor. Final processor.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 6
• EPA 608 / course relevance: Core

Disposal-Recovery Person

• Category: Recovery and Evacuation
• Concise definition: A person who removes refrigerant from an appliance specifically so that the appliance can proceed to final disposal. For small appliances, a technician-certification exception may apply, while recovery requirements remain.
• Expanded explanation: —
• Related term(s): Recovery Before Disposal
• Commonly confused with: —
• Applicable module(s): 7
• EPA 608 / course relevance: Type I

Dissolved Refrigerant

• Category: Refrigerants, Blends, and Lubricants
• Concise definition: Dissolved refrigerant is refrigerant held in solution within compressor oil or another lubricant rather than existing as a separate free liquid or vapor phase.
• Expanded explanation: —
• Related term(s): Refrigerant
• Commonly confused with: —
• Applicable module(s): 9
• EPA 608 / course relevance: Type III

DOT

• Category: Disposal, Cylinders, and Shipping
• Concise definition: U.S. Department of Transportation, the federal department whose hazardous-materials rules affect refrigerant-cylinder transportation and shipping.
• Expanded explanation: DOT requirements are separate from EPA Section 608 certification requirements but are relevant when refrigerant cylinders are transported or offered for transportation.
• Related term(s): Hazardous Materials Regulations (HMR); DOT Specification Cylinder
• Commonly confused with: EPA
• Applicable module(s): 5, 6, 10, 11
• EPA 608 / course relevance: Core

DOT Specification Cylinder

• Category: Disposal, Cylinders, and Shipping
• Concise definition: A cylinder manufactured to a specification prescribed or recognized under the U.S. DOT Hazardous Materials Regulations.
• Expanded explanation: —
• Related term(s): Recovery Cylinder
• Commonly confused with: —
• Applicable module(s): 6
• EPA 608 / course relevance: Core

Downstream Relief Valve

• Category: Safety
• Concise definition: A pressure-relief device placed on the regulated side of the nitrogen setup to protect downstream hoses, tools, and equipment from excessive pressure.
• Expanded explanation: —
• Related term(s): Pressure-Relief Device
• Commonly confused with: —
• Applicable module(s): 6
• EPA 608 / course relevance: Core

Drop-In Replacement

• Category: General HVAC/R and Service
• Concise definition: A drop-in replacement is an informal term suggesting that one refrigerant can replace another with little or no modification. This course does not treat any substitute as universally drop-in.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 3
• EPA 608 / course relevance: Core

Dry Nitrogen

• Category: Safety
• Concise definition: Dry nitrogen is nitrogen with sufficiently low moisture content for refrigeration service. It is commonly used for: Pressure testing. Purging. Breaking a vacuum during dehydration.
• Expanded explanation: —
• Related term(s): Pressure Regulator; Downstream Relief Valve
• Commonly confused with: —
• Applicable module(s): 5, 6
• EPA 608 / course relevance: Core

E

Electronic Leak Detector

• Category: Leak Repair and Recordkeeping
• Concise definition: An electronic leak detector uses a sensor designed to respond to a specified refrigerant or gas and is used to survey and locate leaks.
• Expanded explanation: —
• Related term(s): Ultrasonic Leak Detector
• Commonly confused with: —
• Applicable module(s): 6, 8
• EPA 608 / course relevance: Core, Type II

Emergency Equipment Shutdown

• Category: Safety
• Concise definition: A control provided to stop specified refrigeration machinery or mechanical equipment during an emergency. The exact equipment affected depends on the applicable design.
• Expanded explanation: —
• Related term(s): Emergency Ventilation
• Commonly confused with: —
• Applicable module(s): 6
• EPA 608 / course relevance: Core

Emergency Ventilation

• Category: Safety
• Concise definition: Mechanical ventilation intended to remove leaked refrigerant and reduce hazardous concentration during an abnormal release.
• Expanded explanation: —
• Related term(s): Emergency Equipment Shutdown
• Commonly confused with: —
• Applicable module(s): 6
• EPA 608 / course relevance: Core

Emission

• Category: Regulatory and Environmental
• Concise definition: An emission is the release of refrigerant into the atmosphere.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 1
• EPA 608 / course relevance: Core

Employer Purchase

• Category: Regulatory and Environmental
• Concise definition: An employer purchase occurs when a business or facility purchases refrigerant based on its current employment of at least one properly certified technician.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 2
• EPA 608 / course relevance: Core

End-Use

• Category: General HVAC/R and Service
• Concise definition: An end-use is the specific equipment or application category in which a substitute refrigerant is evaluated and used.
• Expanded explanation: —
• Related term(s): Use Condition
• Commonly confused with: —
• Applicable module(s): 3
• EPA 608 / course relevance: Core

Enforcement

• Category: Regulatory and Environmental
• Concise definition: Enforcement is the use of inspections, orders, penalties, litigation, certification actions, or other authorities to require compliance.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 2
• EPA 608 / course relevance: Core

EPA

• Category: Certification, Examination, and Study
• Concise definition: U.S. Environmental Protection Agency, the federal agency that administers the Section 608 refrigerant-management program.
• Expanded explanation: In this course, EPA is the primary federal agency source for Section 608 guidance, test topics, approved certifying organizations, and refrigerant-management information.
• Related term(s): Clean Air Act; Section 608
• Commonly confused with: State or local HVAC licensing authority
• Applicable module(s): 1–11
• EPA 608 / course relevance: Core; all certification types

EPA-Certified Refrigerant Reclaimer

• Category: Recovery and Evacuation
• Concise definition: An EPA-certified refrigerant reclaimer is an organization certified by EPA to reprocess used refrigerant and verify that applicable reclamation requirements are satisfied before the refrigerant is sold for use to a new owner.
• Expanded explanation: —
• Related term(s): Reclaim; Reclaimed Refrigerant
• Commonly confused with: —
• Applicable module(s): 5
• EPA 608 / course relevance: Core

Equilibrium

• Category: General HVAC/R and Service
• Concise definition: Equilibrium is a stable thermodynamic condition in which the refrigerant phases, temperature, and pressure are sufficiently stable for the intended comparison.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 4
• EPA 608 / course relevance: Core

Equipment Nameplate

• Category: Service Tools and Connections
• Concise definition: An equipment nameplate is the manufacturer’s permanent identification plate or label that provides equipment data, including the intended refrigerant when applicable.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 3
• EPA 608 / course relevance: Core

Error Log

• Category: Certification, Examination, and Study
• Concise definition: An error log is a structured record of missed, guessed, or uncertain questions and the actions taken to correct them.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 1
• EPA 608 / course relevance: Core

Evacuation

• Category: Recovery and Evacuation
• Concise definition: Evacuation is lowering the pressure in a refrigeration system to remove gas. The term can refer to: EPA refrigerant-removal vacuum requirements, or Deep vacuum used for dehydration before charging. The context must be identified.
• Expanded explanation: —
• Related term(s): Deep Evacuation
• Commonly confused with: Recover
• Applicable module(s): 5
• EPA 608 / course relevance: Core

Evacuation Level

• Category: Recovery and Evacuation
• Concise definition: An evacuation level is the required refrigerant-removal endpoint specified by the applicable Section 608 rule. Depending on the equipment category, the endpoint may be expressed in: in. Hg vacuum. mm Hg absolute. Percentage recovered.
• Expanded explanation: Another specified recovery condition.
• Related term(s): Evacuation
• Commonly confused with: —
• Applicable module(s): 5, 8
• EPA 608 / course relevance: Core, Type II

Evaporation

• Category: Refrigeration Cycle and Thermodynamics
• Concise definition: Evaporation is the phase change from liquid to vapor. During refrigeration-system evaporation, refrigerant absorbs heat.
• Expanded explanation: —
• Related term(s): Flash Evaporation
• Commonly confused with: —
• Applicable module(s): 3
• EPA 608 / course relevance: Core

Evaporator

• Category: Refrigeration Cycle and Thermodynamics
• Concise definition: An evaporator is a heat exchanger in which low-pressure refrigerant absorbs heat from the cooled space, product, or process and evaporates toward vapor.
• Expanded explanation: —
• Related term(s): Heat Absorption; Suction Line
• Commonly confused with: —
• Applicable module(s): 4, 8, 9
• EPA 608 / course relevance: Core, Type II, Type III

Evaporator Charging Valve

• Category: Service Tools and Connections
• Concise definition: The evaporator charging valve is the manufacturer-designated refrigerant service connection associated with the evaporator and used for Type III centrifugal-chiller charging.
• Expanded explanation: —
• Related term(s): Charging Valve
• Commonly confused with: —
• Applicable module(s): 9
• EPA 608 / course relevance: Type III

Evaporator Superheat

• Category: Refrigeration Cycle and Thermodynamics
• Concise definition: Evaporator superheat is superheat evaluated at or near the evaporator outlet.
• Expanded explanation: —
• Related term(s): Evaporator
• Commonly confused with: —
• Applicable module(s): 4
• EPA 608 / course relevance: Core

Evaporator Water Box

• Category: Refrigeration Cycle and Thermodynamics
• Concise definition: An evaporator water box directs chilled water into or out of the evaporator tube bundle.
• Expanded explanation: —
• Related term(s): Condenser Water Box
• Commonly confused with: —
• Applicable module(s): 9
• EPA 608 / course relevance: Type III

Excessive Superheat

• Category: Refrigeration Cycle and Thermodynamics
• Concise definition: Excessive superheat means the refrigerant vapor temperature is substantially above the saturation temperature corresponding to the measured evaporator pressure.
• Expanded explanation: In a direct-expansion system it can indicate a starved evaporator and possible low refrigerant charge.
• Related term(s): Superheat
• Commonly confused with: —
• Applicable module(s): 8
• EPA 608 / course relevance: Type II

Exempt Substitute

• Category: Refrigerants, Blends, and Lubricants
• Concise definition: An exempt substitute is a substitute refrigerant that EPA has exempted from the Section 608 venting prohibition in the end use specified by the regulation.
• Expanded explanation: —
• Related term(s): Non-Exempt Substitute
• Commonly confused with: —
• Applicable module(s): 2
• EPA 608 / course relevance: Core

F

Face Shield

• Category: Safety
• Concise definition: Secondary face protection used when a hazard assessment indicates additional protection is needed. A face shield does not automatically replace primary eye protection.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 6
• EPA 608 / course relevance: Core

Factory Charged

• Category: Type I
• Concise definition: Factory charged means the appliance receives its refrigerant charge as part of the factory manufacturing process rather than requiring establishment of the appliance charge during field installation.
• Expanded explanation: —
• Related term(s): Factory Manufactured
• Commonly confused with: —
• Applicable module(s): 7
• EPA 608 / course relevance: Type I

Factory Hermetically Sealed

• Category: Type I
• Concise definition: For the small-appliance definition, the appliance refrigerant circuit is sealed at the factory as part of the completed appliance. This term should not be confused with the separate compressor-construction term hermetic compressor.
• Expanded explanation: —
• Related term(s): Factory Charged
• Commonly confused with: —
• Applicable module(s): 7
• EPA 608 / course relevance: Type I

Factory Manufactured

• Category: Type I
• Concise definition: For Type I classification, the appliance must be fully manufactured at a factory rather than requiring field assembly of the refrigeration circuit into the completed appliance.
• Expanded explanation: —
• Related term(s): Factory Charged
• Commonly confused with: —
• Applicable module(s): 7
• EPA 608 / course relevance: Type I

Failed Compressor

• Category: Refrigeration Cycle and Thermodynamics
• Concise definition: A compressor that is not capable of operating as required to provide refrigerant pumping during the recovery procedure. For this section: failed compressor = compressor cannot be used as the appliance’s recovery-driving pump
• Expanded explanation: —
• Related term(s): Compressor
• Commonly confused with: Operating Compressor
• Applicable module(s): 7
• EPA 608 / course relevance: Type I

Falsified Record

• Category: Leak Repair and Recordkeeping
• Concise definition: A falsified record intentionally misrepresents a material fact, activity, quantity, date, person, test, or result.
• Expanded explanation: —
• Related term(s): Record Retention Period
• Commonly confused with: —
• Applicable module(s): 2
• EPA 608 / course relevance: Core

Field-Assembled Equipment

• Category: Type I
• Concise definition: Equipment whose refrigerant circuit or major refrigeration components must be assembled or connected in the field, rather than existing as a fully manufactured, factory charged, hermetically sealed appliance.
• Expanded explanation: —
• Related term(s): Field-Connected Split System
• Commonly confused with: —
• Applicable module(s): 7
• EPA 608 / course relevance: Type I

Field-Connected Split System

• Category: Type I
• Concise definition: A refrigeration or air-conditioning system in which major components such as the condenser and evaporator are connected by refrigerant piping during installation. Such systems generally should not be classified as Type I from charge alone.
• Expanded explanation: —
• Related term(s): Refrigerated-Cargo System
• Commonly confused with: —
• Applicable module(s): 7
• EPA 608 / course relevance: Type I

Filter-Drier

• Category: Type II
• Concise definition: A filter-drier is a refrigerant-system component that filters particulate contamination and contains desiccant to remove moisture. Special burnout driers can also provide acid-cleanup capability.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 3, 4, 8
• EPA 608 / course relevance: Core, Type II

Final Disposer

• Category: Disposal, Cylinders, and Shipping
• Concise definition: A common EPA public-guidance term for the final person/entity in the disposal chain. The regulation uses final processor.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 6
• EPA 608 / course relevance: Core

Final Processor

• Category: Type I
• Concise definition: The person taking the final step in the disposal process for a small appliance, MVAC, or MVAC-like appliance. Examples include scrap recyclers and landfill operators.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 6, 7
• EPA 608 / course relevance: Core, Type I

First-Aid Measures

• Category: Safety
• Concise definition: Immediate care instructions for an exposed person before professional medical treatment is available. SDS Section 4 provides the product-specific first-aid information.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 6
• EPA 608 / course relevance: Core

Flammability

• Category: Safety
• Concise definition: The ability of a substance to ignite and propagate flame under specified conditions.
• Expanded explanation: —
• Related term(s): Flammability Class 1
• Commonly confused with: —
• Applicable module(s): 6
• EPA 608 / course relevance: Core

Flammability Class 1

• Category: Safety
• Concise definition: A refrigerant classification indicating no flame propagation under the specified Standard 34 test conditions.
• Expanded explanation: —
• Related term(s): Flammability Class 2
• Commonly confused with: —
• Applicable module(s): 6
• EPA 608 / course relevance: Core

Flammability Class 2

• Category: Safety
• Concise definition: A lower-flammability classification for refrigerants that exhibit flame propagation but are not assigned to the 2L low-burning-velocity subclass.
• Expanded explanation: —
• Related term(s): Flammability Class 2L
• Commonly confused with: Flammability Class 2L
• Applicable module(s): 6
• EPA 608 / course relevance: Core

Flammability Class 2L

• Category: Safety
• Concise definition: A lower-flammability subclass characterized by low burning velocity.
• Expanded explanation: —
• Related term(s): Flammability Class 2
• Commonly confused with: Flammability Class 2
• Applicable module(s): 6
• EPA 608 / course relevance: Core

Flammability Class 3

• Category: Safety
• Concise definition: The higher-flammability refrigerant classification.
• Expanded explanation: —
• Related term(s): Flammability Class 1
• Commonly confused with: —
• Applicable module(s): 6
• EPA 608 / course relevance: Core

Flammable Range

• Category: Safety
• Concise definition: The concentration range in which a fuel-air mixture can propagate flame under specified conditions. The lower and upper limits are refrigerant-specific.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 6
• EPA 608 / course relevance: Core

Flash Evaporation

• Category: Refrigeration Cycle and Thermodynamics
• Concise definition: Flash evaporation is the rapid vaporization of part of a liquid when pressure falls below the saturation pressure corresponding to its temperature.
• Expanded explanation: —
• Related term(s): Evaporation
• Commonly confused with: —
• Applicable module(s): 9
• EPA 608 / course relevance: Type III

Flash Gas

• Category: Refrigeration Cycle and Thermodynamics
• Concise definition: Flash gas is vapor formed when part of a liquid refrigerant vaporizes as its pressure is reduced, such as across a metering device.
• Expanded explanation: —
• Related term(s): Flash Evaporation
• Commonly confused with: —
• Applicable module(s): 4
• EPA 608 / course relevance: Core

Floodback

• Category: Refrigeration Cycle and Thermodynamics
• Concise definition: Floodback is the return of liquid refrigerant from the evaporator toward the compressor during operation.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 4
• EPA 608 / course relevance: Core

Flow Restriction

• Category: General HVAC/R and Service
• Concise definition: A flow restriction is any component or condition that reduces refrigerant flow, such as a small fitting, valve core, partially closed valve, restricted filter, kinked hose, or undersized hose.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 5
• EPA 608 / course relevance: Core

Fluorescent Dye

• Category: General HVAC/R and Service
• Concise definition: A compatible tracer added to or already present in a refrigeration system that becomes visible under an appropriate inspection light after escaping with refrigerant oil.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 6
• EPA 608 / course relevance: Core

Follow-Up Verification Test

• Category: Leak Repair and Recordkeeping
• Concise definition: A test performed after a successful initial verification test and after the appliance has returned to normal operating characteristics and conditions to confirm that a covered leak repair remains successful.
• Expanded explanation: Use the current applicable rule for timing and documentation requirements.
• Related term(s): Initial Verification Test
• Commonly confused with: Initial Verification Test
• Applicable module(s): 8
• EPA 608 / course relevance: Type II

Formal Laboratory Coursework

• Category: Certification, Examination, and Study
• Concise definition: Formal laboratory coursework is structured, course-driven educational work conducted as part of an academic or training program. EPA distinguishes it from ordinary on-the-job training.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 1
• EPA 608 / course relevance: Core

Four Inches of Mercury Vacuum

• Category: Recovery and Evacuation
• Concise definition: A pressure endpoint permitted as an alternative small-appliance recovery requirement under current §82.156(b). It is written: 4 in. Hg vacuum and should not be confused with: 4 in. Hg absolute. 25 mm Hg absolute. Deep-vacuum micron values.
• Expanded explanation: —
• Related term(s): Inches of Mercury Vacuum
• Commonly confused with: —
• Applicable module(s): 7
• EPA 608 / course relevance: Type I

Fractionation

• Category: Refrigerants, Blends, and Lubricants
• Concise definition: Fractionation is a change in blend composition caused by preferential separation, removal, or loss of components between the liquid and vapor phases.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 3
• EPA 608 / course relevance: Core

Free Radical

• Category: Regulatory and Environmental
• Concise definition: A free radical is an atom or molecule with an unpaired electron. Free radicals are often highly reactive.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 2
• EPA 608 / course relevance: Core

Freeze-Up

• Category: Type III
• Concise definition: Formation of ice in or around a chiller water passage due to sufficiently low temperature.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 9
• EPA 608 / course relevance: Type III

Frostbite

• Category: Safety
• Concise definition: A freezing injury to body tissue caused by sufficiently low temperature. In refrigerant service, frostbite can result when liquid refrigerant or a rapidly expanding refrigerant stream removes heat rapidly from skin or eye tissue.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 6
• EPA 608 / course relevance: Core

Full Charge

• Category: General HVAC/R and Service
• Concise definition: The amount of refrigerant required for normal operating characteristics and conditions of an appliance, determined by an allowed method such as manufacturer data, engineering calculation, measurement, or an established range.
• Expanded explanation: Do not confuse full charge with the amount of refrigerant remaining in a leaking appliance or with a nameplate value that may not reflect field modifications.
• Related term(s): —
• Commonly confused with: Nameplate Charge
• Applicable module(s): 5, 7, 8
• EPA 608 / course relevance: Core, Type I, Type II

Full-Charge Threshold

• Category: Type II
• Concise definition: A full-charge threshold is the minimum refrigerant charge at which a particular leak-repair framework becomes applicable when its other conditions are met.
• Expanded explanation: —
• Related term(s): Appliance Full Charge
• Commonly confused with: —
• Applicable module(s): 8
• EPA 608 / course relevance: Type II

Functional Compressor

• Category: Refrigeration Cycle and Thermodynamics
• Concise definition: An appliance compressor capable of operating during the recovery procedure. For recovery equipment manufactured on or after November 15, 1993, a functional compressor corresponds to the 90% percentage-recovery requirement.
• Expanded explanation: —
• Related term(s): Compressor
• Commonly confused with: Nonfunctional Compressor
• Applicable module(s): 7
• EPA 608 / course relevance: Type I

G

Gas-Imaging Camera

• Category: General HVAC/R and Service
• Concise definition: An imaging device capable of visualizing certain gas releases when designed for the target gas and application. EPA currently lists gas imaging as a potential leak-inspection method.
• Expanded explanation: —
• Related term(s): Noncondensable Gas
• Commonly confused with: —
• Applicable module(s): 6
• EPA 608 / course relevance: Core

Gauge Pressure

• Category: Service Tools and Connections
• Concise definition: Gauge pressure is pressure measured relative to local atmospheric pressure. It is commonly expressed in psig. HVAC manifold gauges ordinarily display gauge pressure.
• Expanded explanation: —
• Related term(s): Absolute Pressure; psig
• Commonly confused with: Absolute Pressure
• Applicable module(s): 4, 8
• EPA 608 / course relevance: Core, Type II

Global-Warming Potential

• Category: Refrigerants, Blends, and Lubricants
• Concise definition: Global-warming potential, or GWP, compares a gas’s integrated warming effect with that of the same mass of carbon dioxide over a stated time horizon.
• Expanded explanation: —
• Related term(s): Ozone-Depletion Potential; Carbon Dioxide Equivalent
• Commonly confused with: Ozone-Depletion Potential
• Applicable module(s): 2
• EPA 608 / course relevance: Core

Good-Faith Attempt

• Category: General HVAC/R and Service
• Concise definition: A good-faith attempt is an actual effort to comply with recovery, recycling, disposal, equipment, certification, and service-practice requirements while minimizing emissions.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 2
• EPA 608 / course relevance: Core

Ground-Level Ozone

• Category: Regulatory and Environmental
• Concise definition: Ground-level ozone is ozone in the lower atmosphere near the Earth’s surface. It is a harmful air pollutant and a major component of smog.
• Expanded explanation: —
• Related term(s): Ozone
• Commonly confused with: —
• Applicable module(s): 2
• EPA 608 / course relevance: Core

GWP

• Category: Refrigerants, Blends, and Lubricants
• Concise definition: Global-warming potential; a relative climate-impact metric comparing the heat-trapping effect of a greenhouse gas over a specified time horizon.
• Expanded explanation: GWP is distinct from ODP and does not by itself determine Section 608 pressure classification or safety class.
• Related term(s): Global-Warming Potential; Carbon Dioxide Equivalent
• Commonly confused with: ODP
• Applicable module(s): 2, 8, 10, 11
• EPA 608 / course relevance: Core; Type II

H

Halogen

• Category: Refrigerants, Blends, and Lubricants
• Concise definition: A halogen is an element in a chemical family that includes fluorine, chlorine, bromine, and iodine. Chlorine and bromine are the halogens most important to the ozone-depletion processes emphasized in this course.
• Expanded explanation: —
• Related term(s): Halon
• Commonly confused with: —
• Applicable module(s): 2
• EPA 608 / course relevance: Core

Halon

• Category: Refrigerants, Blends, and Lubricants
• Concise definition: A halon is a bromine-containing compound historically used primarily in fire-suppression applications. Halons are important ozone-depleting substances.
• Expanded explanation: —
• Related term(s): Halogen
• Commonly confused with: —
• Applicable module(s): 2
• EPA 608 / course relevance: Core

Hazard Assessment

• Category: General HVAC/R and Service
• Concise definition: An evaluation of workplace hazards used to determine whether PPE is necessary and what PPE is appropriate.
• Expanded explanation: —
• Related term(s): Hazard Label
• Commonly confused with: —
• Applicable module(s): 6
• EPA 608 / course relevance: Core

Hazard Class / Division

• Category: Disposal, Cylinders, and Shipping
• Concise definition: A DOT transportation classification describing the primary hazard of a material. For gases, examples include: Division 2.1 — flammable gas. Division 2.2 — non-flammable, nonpoisonous compressed gas. Division 2.3 — gas poisonous by inhalation.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 6
• EPA 608 / course relevance: Core

Hazard Label

• Category: General HVAC/R and Service
• Concise definition: The standardized diamond-shaped package label used to communicate the applicable hazard class/division when required.
• Expanded explanation: —
• Related term(s): Hazard Assessment
• Commonly confused with: —
• Applicable module(s): 6
• EPA 608 / course relevance: Core

Hazardous Atmosphere

• Category: Safety
• Concise definition: An atmosphere capable of causing death, incapacitation, impairment of self-rescue, injury, or acute illness because of oxygen level, flammable materials, toxic contaminants, or another serious atmospheric condition.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 6
• EPA 608 / course relevance: Core

Hazardous Materials Regulations (HMR)

• Category: General HVAC/R and Service
• Concise definition: The U.S. DOT/PHMSA regulations for hazardous-material transportation, primarily in 49 CFR Parts 171–180 for the subjects covered in this section.
• Expanded explanation: —
• Related term(s): Hazardous Materials Table
• Commonly confused with: —
• Applicable module(s): 6
• EPA 608 / course relevance: Core

Hazardous Materials Table

• Category: General HVAC/R and Service
• Concise definition: The table in 49 CFR §172.101 that provides shipping names, hazard classifications, identification numbers, packaging references, special provisions, and mode-specific information.
• Expanded explanation: —
• Related term(s): Hazardous Materials Regulations (HMR)
• Commonly confused with: —
• Applicable module(s): 6
• EPA 608 / course relevance: Core

HCFC

• Category: Refrigerants, Blends, and Lubricants
• Concise definition: Hydrochlorofluorocarbon; a refrigerant family containing hydrogen, chlorine, fluorine, and carbon.
• Expanded explanation: HCFCs have nonzero ozone-depletion potential but generally lower ODP than CFCs; R-22 and R-123 are common course examples.
• Related term(s): Hydrochlorofluorocarbon; Ozone-Depleting Substance
• Commonly confused with: CFC; HFC
• Applicable module(s): 2, 3, 8, 9, 10, 11
• EPA 608 / course relevance: Core; Type II; Type III

Head Pressure

• Category: Pressure, Vacuum, and Measurement
• Concise definition: Head pressure is a common technician term for the high-side or condensing pressure of a refrigeration system.
• Expanded explanation: —
• Related term(s): Back Pressure
• Commonly confused with: —
• Applicable module(s): 3
• EPA 608 / course relevance: Core

Heat

• Category: Refrigeration Cycle and Thermodynamics
• Concise definition: Heat is energy transferred because of a temperature difference.
• Expanded explanation: —
• Related term(s): Latent Heat
• Commonly confused with: —
• Applicable module(s): 3
• EPA 608 / course relevance: Core

Heat Absorption

• Category: Refrigeration Cycle and Thermodynamics
• Concise definition: Heat absorption is the transfer of heat into the refrigerant. In the basic vapor-compression cycle, useful heat absorption occurs in the evaporator.
• Expanded explanation: —
• Related term(s): Heat
• Commonly confused with: —
• Applicable module(s): 4
• EPA 608 / course relevance: Core

Heat Rejection

• Category: Refrigeration Cycle and Thermodynamics
• Concise definition: Heat rejection is the transfer of heat out of the refrigerant. In the basic vapor-compression cycle, the main heat-rejection process occurs in the condenser.
• Expanded explanation: —
• Related term(s): Heat
• Commonly confused with: —
• Applicable module(s): 4
• EPA 608 / course relevance: Core

Heater Blanket

• Category: Service Tools and Connections
• Concise definition: An approved external heating device used to warm part of a chiller or refrigerant system in a controlled manner.
• Expanded explanation: For Type III work, controlled warming can be used where appropriate to raise refrigerant pressure without an open flame.
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 9
• EPA 608 / course relevance: Type III

Hermetic Compressor

• Category: Refrigeration Cycle and Thermodynamics
• Concise definition: A hermetic compressor contains the motor and compressor within a sealed shell. A hermetic compressor alone does not make the entire appliance a Type I small appliance.
• Expanded explanation: —
• Related term(s): Compressor
• Commonly confused with: —
• Applicable module(s): 7, 8
• EPA 608 / course relevance: Type I, Type II

HFC

• Category: Refrigerants, Blends, and Lubricants
• Concise definition: Hydrofluorocarbon; a fluorinated refrigerant family containing hydrogen, fluorine, and carbon but no chlorine.
• Expanded explanation: HFCs have zero ODP but may have significant GWP and remain subject to applicable refrigerant-management and separate HFC regulatory requirements.
• Related term(s): Hydrofluorocarbon; HFO; Substitute Refrigerant
• Commonly confused with: Zero ODP does not mean unrestricted venting
• Applicable module(s): 2, 3, 8, 10, 11
• EPA 608 / course relevance: Core; Type II

HFO

• Category: Refrigerants, Blends, and Lubricants
• Concise definition: Hydrofluoroolefin; an unsaturated fluorinated refrigerant family commonly used in lower-GWP refrigerants and blends.
• Expanded explanation: HFOs have zero ODP and may have different flammability classifications and service requirements from older A1 refrigerants.
• Related term(s): Hydrofluoroolefin; HFC; Substitute Refrigerant
• Commonly confused with: HFC
• Applicable module(s): 2, 3, 6, 10, 11
• EPA 608 / course relevance: Core

High Side

• Category: Refrigeration Cycle and Thermodynamics
• Concise definition: The high side is the high-pressure region of the basic refrigeration cycle from the compressor discharge to the metering-device inlet.
• Expanded explanation: —
• Related term(s): Low Side
• Commonly confused with: High-Pressure Appliance
• Applicable module(s): 4, 7
• EPA 608 / course relevance: Core, Type I

High-Pressure Appliance

• Category: Pressure, Vacuum, and Measurement
• Concise definition: An appliance using a refrigerant with a liquid-phase saturation pressure between 170 psia and 355 psia at 104°F.
• Expanded explanation: High-pressure appliances are within Type II certification unless another appliance classification or exclusion controls.
• Related term(s): Very-High-Pressure Appliance
• Commonly confused with: High Side
• Applicable module(s): 1, 8
• EPA 608 / course relevance: Core, Type II

High-Pressure Cutout

• Category: Pressure, Vacuum, and Measurement
• Concise definition: A protective control that stops or interrupts equipment operation when pressure rises above its permitted limit.
• Expanded explanation: For traditional Type III examination preparation, the low-pressure recovery-unit high-pressure cutout value used in this course is 10 psig; do not apply that value to unrelated equipment.
• Related term(s): Recovery Machine; Pressure-Relief Device
• Commonly confused with: —
• Applicable module(s): 8, 9
• EPA 608 / course relevance: Type II, Type III

High-Pressure Gauge

• Category: Service Tools and Connections
• Concise definition: A high-pressure gauge measures pressure on the high-pressure side of the refrigeration system.
• Expanded explanation: —
• Related term(s): Gauge Pressure
• Commonly confused with: —
• Applicable module(s): 4
• EPA 608 / course relevance: Core

High-Pressure Liquid

• Category: Refrigeration Cycle and Thermodynamics
• Concise definition: High-pressure liquid is the typical simplified refrigerant state leaving the condenser and approaching the metering device.
• Expanded explanation: —
• Related term(s): High-Pressure Vapor
• Commonly confused with: —
• Applicable module(s): 4
• EPA 608 / course relevance: Core

High-Pressure Vapor

• Category: Refrigeration Cycle and Thermodynamics
• Concise definition: High-pressure vapor is the typical refrigerant state leaving the compressor and entering the condenser.
• Expanded explanation: —
• Related term(s): Low-Pressure Vapor
• Commonly confused with: —
• Applicable module(s): 4
• EPA 608 / course relevance: Core

High-Side Access

• Category: Type I
• Concise definition: A service connection that communicates with the high-pressure side of the refrigeration circuit. Typical high-side regions include: Compressor discharge line. Condenser. Liquid line upstream of the metering restriction.
• Expanded explanation: The exact access location depends on appliance design.
• Related term(s): Low-Side Access
• Commonly confused with: Low-Side Access
• Applicable module(s): 7
• EPA 608 / course relevance: Type I

High-Side Recovery

• Category: Recovery and Evacuation
• Concise definition: A recovery technique in which refrigerant is removed through an access connection on the high side of the appliance. For the conventional Type I system-dependent method with an operating compressor, the compressor helps move refrigerant toward this connection.
• Expanded explanation: —
• Related term(s): Liquid Recovery
• Commonly confused with: —
• Applicable module(s): 7
• EPA 608 / course relevance: Type I

Historical Rule

• Category: Regulatory and Environmental
• Concise definition: A historical rule applied during a previous period but is not the controlling current requirement.
• Expanded explanation: —
• Related term(s): Scheduled Rule
• Commonly confused with: Current Rule
• Applicable module(s): 2
• EPA 608 / course relevance: Core

Hydrocarbon

• Category: Refrigerants, Blends, and Lubricants
• Concise definition: A hydrocarbon contains only hydrogen and carbon. Common hydrocarbon refrigerants have zero ODP and low GWP but are flammable.
• Expanded explanation: —
• Related term(s): Hydrofluorocarbon
• Commonly confused with: —
• Applicable module(s): 2
• EPA 608 / course relevance: Core

Hydrochlorofluorocarbon

• Category: Refrigerants, Blends, and Lubricants
• Concise definition: A hydrochlorofluorocarbon, or HCFC, is a compound containing hydrogen, chlorine, fluorine, and carbon. HCFCs generally have lower ozone-depletion potentials than CFCs but are still ozone-depleting substances.
• Expanded explanation: —
• Related term(s): Chlorofluorocarbon; Hydrofluorocarbon
• Commonly confused with: —
• Applicable module(s): 2
• EPA 608 / course relevance: Core

Hydrofluorocarbon

• Category: Refrigerants, Blends, and Lubricants
• Concise definition: A hydrofluorocarbon, or HFC, contains hydrogen, fluorine, and carbon without chlorine. HFCs have zero ODP, but many have significant GWP.
• Expanded explanation: —
• Related term(s): Hydrofluoroolefin; Substitute Refrigerant
• Commonly confused with: —
• Applicable module(s): 2
• EPA 608 / course relevance: Core

Hydrofluoroolefin

• Category: Refrigerants, Blends, and Lubricants
• Concise definition: A hydrofluoroolefin, or HFO, is an unsaturated fluorinated compound containing a carbon-carbon double bond. Common HFO refrigerants have zero ODP and low GWP.
• Expanded explanation: —
• Related term(s): Hydrofluorocarbon; Substitute Refrigerant
• Commonly confused with: —
• Applicable module(s): 2
• EPA 608 / course relevance: Core

Hydrogen Chloride

• Category: General HVAC/R and Service
• Concise definition: A corrosive chlorine-containing compound that can form during thermal decomposition of some chlorine-containing refrigerants.
• Expanded explanation: —
• Related term(s): Hydrogen Fluoride
• Commonly confused with: —
• Applicable module(s): 6
• EPA 608 / course relevance: Core

Hydrogen Fluoride

• Category: General HVAC/R and Service
• Concise definition: A highly hazardous fluorine-containing compound that can form during thermal decomposition of some fluorinated refrigerants.
• Expanded explanation: —
• Related term(s): Hydrogen Chloride
• Commonly confused with: —
• Applicable module(s): 6
• EPA 608 / course relevance: Core

Hydrostatic Tube Test Kit

• Category: Service Tools and Connections
• Concise definition: A hydrostatic tube test kit is equipment used to test heat-exchanger tubes for leakage using controlled liquid pressure. It is a classic Type III exam answer for tube-leak testing.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 9
• EPA 608 / course relevance: Type III

Hygroscopic

• Category: General HVAC/R and Service
• Concise definition: Hygroscopic describes a material that attracts or absorbs moisture from the surrounding environment.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 3
• EPA 608 / course relevance: Core

I

Identification Number

• Category: Disposal, Cylinders, and Shipping
• Concise definition: The UN, NA, or ID number assigned to a hazardous material for transportation.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 6
• EPA 608 / course relevance: Core

Ignition Source

• Category: Safety
• Concise definition: A flame, spark, electrical arc, hot surface, or other energy source capable of igniting a specific combustible mixture under the conditions present.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 6
• EPA 608 / course relevance: Core

Immediately Dangerous to Life or Health (IDLH)

• Category: Safety
• Concise definition: A condition posing an immediate or delayed threat to life, irreversible adverse health effects, or interference with a person’s ability to escape unaided.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 6
• EPA 608 / course relevance: Core

Inches of Mercury Vacuum

• Category: Recovery and Evacuation
• Concise definition: Inches of mercury vacuum (in. Hg vacuum) is a gauge-style vacuum measurement referenced to atmospheric pressure. In Table 1, the reference is standard atmospheric pressure of 29.9 in. Hg.
• Expanded explanation: —
• Related term(s): Four Inches of Mercury Vacuum
• Commonly confused with: 25 mm Hg Absolute
• Applicable module(s): 4, 8
• EPA 608 / course relevance: Core, Type II

Incorporated by Reference

• Category: Regulatory and Environmental
• Concise definition: A standard is incorporated by reference when a regulation legally adopts a specified external standard or edition.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 2
• EPA 608 / course relevance: Core

Independent Recovery Compressor

• Category: Recovery and Evacuation
• Concise definition: The compressor or independent refrigerant-moving mechanism contained in a self-contained recovery machine. It is separate from the appliance compressor.
• Expanded explanation: —
• Related term(s): Recovery Compressor
• Commonly confused with: —
• Applicable module(s): 7
• EPA 608 / course relevance: Type I

Industrial-Process Refrigeration

• Category: Type II
• Concise definition: Industrial-process refrigeration refers to complex customized refrigeration appliances directly linked to industrial processes, including qualifying chemical, pharmaceutical, petrochemical, manufacturing, industrial ice, electricity-generation, and ice-rink ap
• Expanded explanation: plications.
• Related term(s): Commercial Refrigeration
• Commonly confused with: —
• Applicable module(s): 8
• EPA 608 / course relevance: Type II

Initial Vapor Charge

• Category: Type III
• Concise definition: The initial vapor charge is the first recharging stage in which refrigerant enters a deeply evacuated low-pressure chiller as vapor to raise pressure and saturation temperature while reducing freeze risk.
• Expanded explanation: —
• Related term(s): Vapor Charging
• Commonly confused with: —
• Applicable module(s): 9
• EPA 608 / course relevance: Type III

Initial Verification Test

• Category: Leak Repair and Recordkeeping
• Concise definition: A leak test performed after a covered repair is completed to verify that the leak has been repaired before refrigerant is added back to the appliance.
• Expanded explanation: It precedes the follow-up verification test under the current Section 608 leak-repair framework.
• Related term(s): Follow-Up Verification Test
• Commonly confused with: Follow-Up Verification Test
• Applicable module(s): 8
• EPA 608 / course relevance: Type II

Injunctive Relief

• Category: General HVAC/R and Service
• Concise definition: Injunctive relief requires a person or organization to take or stop specified actions, such as installing controls, changing procedures, conducting audits, or training employees.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 2
• EPA 608 / course relevance: Core

Inlet Filter

• Category: Service Tools and Connections
• Concise definition: An inlet filter or inlet screen protects the recovery machine from debris entering with the refrigerant. The exact filter type and maintenance procedure depend on the recovery-machine design.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 5
• EPA 608 / course relevance: Core

Intentional Venting

• Category: Regulatory and Environmental
• Concise definition: Intentional venting is the knowing release of regulated refrigerant to the atmosphere during covered activities, except where a specific regulatory allowance or exemption applies.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 1, 2
• EPA 608 / course relevance: Core

Interleaved Practice

• Category: Certification, Examination, and Study
• Concise definition: Interleaved practice mixes related topics so that the student must determine which concept or rule applies.
• Expanded explanation: —
• Related term(s): Retrieval Practice
• Commonly confused with: —
• Applicable module(s): 1
• EPA 608 / course relevance: Core

Isolated Component

• Category: General HVAC/R and Service
• Concise definition: An isolated component is a portion of an appliance separated from the remainder of the refrigerant circuit by suitable valves or other means so refrigerant can be retained elsewhere in the system.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 5
• EPA 608 / course relevance: Core

Isolation Valve

• Category: Type II
• Concise definition: An isolation valve is a valve used to separate one part of a refrigerant circuit from another for operation, control, service, or repair.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 8
• EPA 608 / course relevance: Type II

L

Latent Heat

• Category: Refrigeration Cycle and Thermodynamics
• Concise definition: Latent heat is energy associated with a phase change rather than an ordinary temperature change within a single phase.
• Expanded explanation: —
• Related term(s): Latent Heat of Vaporization
• Commonly confused with: —
• Applicable module(s): 3
• EPA 608 / course relevance: Core

Latent Heat of Vaporization

• Category: Refrigeration Cycle and Thermodynamics
• Concise definition: Latent heat of vaporization is the energy required per unit mass to change saturated liquid to saturated vapor at the same saturation condition.
• Expanded explanation: —
• Related term(s): Latent Heat
• Commonly confused with: —
• Applicable module(s): 3, 9
• EPA 608 / course relevance: Core, Type III

Leak Indicator

• Category: Leak Repair and Recordkeeping
• Concise definition: A leak indicator is a symptom or observation suggesting that refrigerant leakage may have occurred, such as oil residue, low charge, or excessive superheat.
• Expanded explanation: —
• Related term(s): Leak Location
• Commonly confused with: Leak Location
• Applicable module(s): 8
• EPA 608 / course relevance: Type II

Leak Inspection

• Category: Leak Repair and Recordkeeping
• Concise definition: An examination of an appliance using an appropriate method to detect and determine the location of refrigerant leaks.
• Expanded explanation: Methods that only indicate that an appliance may be leaking, without locating the leak, must be paired with a method that can locate the leak when the current rule requires a leak inspection.
• Related term(s): Leak Location; Leak Indicator
• Commonly confused with: Leak Rate
• Applicable module(s): 6, 8
• EPA 608 / course relevance: Core, Type II

Leak Location

• Category: Leak Repair and Recordkeeping
• Concise definition: The physical point or component from which refrigerant or test gas escapes.
• Expanded explanation: —
• Related term(s): Leak Inspection
• Commonly confused with: Leak Indicator
• Applicable module(s): 6
• EPA 608 / course relevance: Core

Leak Rate

• Category: Leak Repair and Recordkeeping
• Concise definition: The rate at which an appliance is losing refrigerant, expressed as the percentage of the appliance’s full charge that would be lost over a 12-month period if the current rate continued.
• Expanded explanation: The applicable regulatory framework determines when the leak rate must be calculated and what trigger rate applies.
• Related term(s): Leak Inspection; Full Charge
• Commonly confused with: Leak Inspection
• Applicable module(s): 8
• EPA 608 / course relevance: Type II

Leak-Test Pressure

• Category: Leak Repair and Recordkeeping
• Concise definition: The controlled pressure established during a leak test so leakage can be detected.
• Expanded explanation: For the traditional Type III examination framework used in this course, low-pressure chiller leak testing is limited to a maximum of 10 psig; treat that as an exam-preparation maximum, not a universal target pressure.
• Related term(s): Standing Pressure Test; Dry Nitrogen
• Commonly confused with: —
• Applicable module(s): 9
• EPA 608 / course relevance: Type III

Leaked-Out Statement

• Category: Leak Repair and Recordkeeping
• Concise definition: A signed statement used when all refrigerant escaped before delivery due to system failure, accident, or another unavoidable occurrence and recovery is not possible. It does not cover deliberate refrigerant release.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 6, 7
• EPA 608 / course relevance: Core, Type I

Legacy Study-Guide Fact

• Category: Regulatory and Environmental
• Concise definition: A legacy study-guide fact is older information that remains useful for historical context but must not be treated as current without verification.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 2
• EPA 608 / course relevance: Core

Limited Certification

• Category: Certification, Examination, and Study
• Concise definition: A limited certification authorizes covered work only within one or more successfully completed equipment-specific categories rather than all three types.
• Expanded explanation: —
• Related term(s): Universal Certification
• Commonly confused with: —
• Applicable module(s): 1
• EPA 608 / course relevance: Core

Liquid Charging

• Category: Type III
• Concise definition: Liquid charging adds refrigerant in the liquid phase after the approved conditions for bulk charging have been established.
• Expanded explanation: —
• Related term(s): Vapor Charging
• Commonly confused with: Vapor Charging
• Applicable module(s): 9
• EPA 608 / course relevance: Type III

Liquid Line

• Category: Refrigeration Cycle and Thermodynamics
• Concise definition: The liquid line carries high-pressure liquid refrigerant from the condenser or receiver toward the metering device.
• Expanded explanation: —
• Related term(s): Liquid Receiver
• Commonly confused with: —
• Applicable module(s): 4, 8
• EPA 608 / course relevance: Core, Type II

Liquid Port

• Category: Type I
• Concise definition: A recovery-cylinder connection commonly attached to an internal dip tube extending toward the lower portion of the cylinder. Many direct recovery-machine procedures connect the recovery-machine outlet to this port.
• Expanded explanation: —
• Related term(s): Vapor Port
• Commonly confused with: —
• Applicable module(s): 7
• EPA 608 / course relevance: Type I

Liquid Receiver

• Category: Refrigeration Cycle and Thermodynamics
• Concise definition: A liquid receiver is a high-side vessel installed after the condenser to collect and store liquid refrigerant and supply liquid to the downstream liquid circuit.
• Expanded explanation: —
• Related term(s): Receiver
• Commonly confused with: Accumulator
• Applicable module(s): 4
• EPA 608 / course relevance: Core

Liquid Recovery

• Category: Recovery and Evacuation
• Concise definition: Liquid recovery removes refrigerant primarily in the liquid state. It is normally faster in terms of refrigerant mass transferred than vapor recovery.
• Expanded explanation: —
• Related term(s): Bulk Liquid Recovery
• Commonly confused with: —
• Applicable module(s): 5, 8
• EPA 608 / course relevance: Core, Type II

Liquid Slugging

• Category: General HVAC/R and Service
• Concise definition: Liquid slugging is damaging compressor operation caused by attempting to compress a significant quantity of incompressible liquid.
• Expanded explanation: —
• Related term(s): Liquid-Vapor Mixture
• Commonly confused with: —
• Applicable module(s): 4
• EPA 608 / course relevance: Core

Liquid-Phase Saturation Pressure

• Category: Refrigeration Cycle and Thermodynamics
• Concise definition: Liquid-phase saturation pressure is the equilibrium pressure corresponding to the saturated liquid-vapor condition at a specified temperature. Section 608 uses the value at $104^{\circ }\text{F}$ as part of the appliance pressure-category definitions.
• Expanded explanation: —
• Related term(s): Saturation Pressure
• Commonly confused with: —
• Applicable module(s): 8
• EPA 608 / course relevance: Type II

Liquid-Vapor Mixture

• Category: General HVAC/R and Service
• Concise definition: A liquid-vapor mixture contains both refrigerant liquid and refrigerant vapor at the same location.
• Expanded explanation: —
• Related term(s): Vapor Density
• Commonly confused with: —
• Applicable module(s): 4
• EPA 608 / course relevance: Core

Low Side

• Category: Refrigeration Cycle and Thermodynamics
• Concise definition: The low side is the low-pressure region of the basic refrigeration cycle from the metering-device outlet through the evaporator to the compressor inlet.
• Expanded explanation: —
• Related term(s): High Side
• Commonly confused with: Low-Pressure Appliance
• Applicable module(s): 4
• EPA 608 / course relevance: Core

Low-Loss Fitting

• Category: Service Tools and Connections
• Concise definition: A connection device between hoses, appliances, or recovery/recycling machines designed to close automatically or manually when disconnected so refrigerant release is minimized.
• Expanded explanation: Low-loss fittings reduce hose and connection losses but do not eliminate the need for proper connection and recovery technique.
• Related term(s): Access Fitting
• Commonly confused with: —
• Applicable module(s): 2, 4, 5, 7
• EPA 608 / course relevance: Core, Type I

Low-Pressure Appliance

• Category: Pressure, Vacuum, and Measurement
• Concise definition: An appliance using a refrigerant with a liquid-phase saturation pressure below 45 psia at 104°F.
• Expanded explanation: Low-pressure appliances are associated with Type III certification.
• Related term(s): High-Pressure Appliance
• Commonly confused with: Low Side
• Applicable module(s): 1, 8, 9
• EPA 608 / course relevance: Core, Type II, Type III

Low-Pressure Recovery Vessel

• Category: Recovery and Evacuation
• Concise definition: A refrigerant-receiving vessel designed for low-pressure recovery service.
• Expanded explanation: The traditional Type III examination framework used in this course associates a 15 psig rupture-disc value with the low-pressure recovery vessel; do not generalize that value to every chiller relief device.
• Related term(s): Passive Recovery
• Commonly confused with: —
• Applicable module(s): 9
• EPA 608 / course relevance: Type III

Low-Pressure Vapor

• Category: Refrigeration Cycle and Thermodynamics
• Concise definition: Low-pressure vapor is the typical refrigerant state leaving the evaporator and entering the compressor.
• Expanded explanation: —
• Related term(s): High-Pressure Vapor
• Commonly confused with: —
• Applicable module(s): 4
• EPA 608 / course relevance: Core

Low-Side Access

• Category: Type I
• Concise definition: A service connection that communicates with the low-pressure side of the refrigeration circuit. Typical low-side regions include: Evaporator. Suction line. Compressor inlet region.
• Expanded explanation: —
• Related term(s): High-Side Access
• Commonly confused with: High-Side Access
• Applicable module(s): 7
• EPA 608 / course relevance: Type I

Lower Flammability Limit (LFL)

• Category: Safety
• Concise definition: The lower refrigerant concentration at which flame propagation can occur under specified test conditions. The LFL is refrigerant-specific and is not the same as the class number.
• Expanded explanation: —
• Related term(s): Flammability
• Commonly confused with: —
• Applicable module(s): 6
• EPA 608 / course relevance: Core

Lowest Access Point

• Category: Service Tools and Connections
• Concise definition: In this Type III teaching context, the lowest access point refers to the traditional low refrigerant-side charging connection associated with the evaporator. It does not mean that any physically lowest fitting is automatically an approved charging port.
• Expanded explanation: —
• Related term(s): Access Point
• Commonly confused with: —
• Applicable module(s): 9
• EPA 608 / course relevance: Type III

Lowest Attainable Level

• Category: Type III
• Concise definition: The lowest attainable level is the lowest pressure that can be reached in a leaking component without substantially contaminating the recovered refrigerant. Under the current leak exception, this pressure may not exceed 0 psig.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 9
• EPA 608 / course relevance: Type III

Lubricant Compatibility

• Category: Refrigerants, Blends, and Lubricants
• Concise definition: Lubricant compatibility means that the lubricant, refrigerant, compressor, system materials, and operating conditions can work together without unacceptable lubrication, chemical, or performance problems.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 3
• EPA 608 / course relevance: Core

M

Machinery Room

• Category: Type II
• Concise definition: A machinery room is a designated space containing refrigeration machinery and meeting applicable safety-standard/code requirements for the installation.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 6, 8
• EPA 608 / course relevance: Core, Type II

Major Maintenance, Service, or Repair

• Category: General HVAC/R and Service
• Concise definition: Maintenance, service, or repair involving removal of a compressor, condenser, evaporator, or auxiliary heat-exchange coil, or uncovering an opening of more than 4 in² of flow area for more than 15 minutes.
• Expanded explanation: This is a regulatory definition; do not treat every repair or component replacement as major work.
• Related term(s): Non-Major Repair; Appliance
• Commonly confused with: Non-Major Repair
• Applicable module(s): 5, 8, 9
• EPA 608 / course relevance: Core, Type II, Type III

Makeup Air

• Category: General HVAC/R and Service
• Concise definition: Replacement air supplied to a room to replace air removed by exhaust ventilation.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 6
• EPA 608 / course relevance: Core

Manifold Gauge Set

• Category: Service Tools and Connections
• Concise definition: A manifold gauge set combines pressure gauges, valves, ports, and hoses so a technician can measure system pressures and control selected service flow paths.
• Expanded explanation: —
• Related term(s): Compound Gauge
• Commonly confused with: —
• Applicable module(s): 4
• EPA 608 / course relevance: Core

Marking

• Category: General HVAC/R and Service
• Concise definition: Required information placed on a package, such as a proper shipping name, identification number, or other package information.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 6
• EPA 608 / course relevance: Core

Materials of Trade

• Category: Disposal, Cylinders, and Shipping
• Concise definition: A specific HMR exception for qualifying hazardous materials transported by motor vehicle in support of a business activity when all conditions of 49 CFR §173.6 are satisfied.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 6
• EPA 608 / course relevance: Core

Medium-Pressure Appliance

• Category: Pressure, Vacuum, and Measurement
• Concise definition: An appliance using a refrigerant with a liquid-phase saturation pressure between 45 psia and 170 psia at 104°F.
• Expanded explanation: Medium-pressure appliances are within Type II certification unless another appliance classification or exclusion controls.
• Related term(s): High-Pressure Appliance
• Commonly confused with: —
• Applicable module(s): 1, 8
• EPA 608 / course relevance: Core, Type II

Metering Device

• Category: Refrigeration Cycle and Thermodynamics
• Concise definition: A metering device controls refrigerant flow into the evaporator and creates the pressure drop between the high-pressure and low-pressure sides of the system.
• Expanded explanation: —
• Related term(s): Throttling; Evaporator
• Commonly confused with: —
• Applicable module(s): 4, 8
• EPA 608 / course relevance: Core, Type II

Micron

• Category: Pressure, Vacuum, and Measurement
• Concise definition: A micron, in refrigeration vacuum work, is one micrometer of mercury absolute pressure. One millimeter of mercury equals 1,000 microns.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 3, 4, 5
• EPA 608 / course relevance: Core

Micron Gauge

• Category: Service Tools and Connections
• Concise definition: A micron gauge is an instrument used to measure deep absolute vacuum in refrigeration systems.
• Expanded explanation: —
• Related term(s): Compound Gauge
• Commonly confused with: —
• Applicable module(s): 5
• EPA 608 / course relevance: Core

Millimeters of Mercury Absolute

• Category: Pressure, Vacuum, and Measurement
• Concise definition: Millimeters of mercury absolute is an absolute-pressure scale referenced to perfect vacuum. Lower values indicate deeper vacuum.
• Expanded explanation: —
• Related term(s): Absolute Pressure
• Commonly confused with: Inches of Mercury Vacuum
• Applicable module(s): 4
• EPA 608 / course relevance: Core

Mineral Oil

• Category: Refrigerants, Blends, and Lubricants
• Concise definition: Mineral oil (MO) is a petroleum-based refrigeration lubricant historically associated with many CFC and HCFC systems.
• Expanded explanation: —
• Related term(s): Alkylbenzene; Polyolester
• Commonly confused with: —
• Applicable module(s): 3
• EPA 608 / course relevance: Core

Miscibility

• Category: Refrigerants, Blends, and Lubricants
• Concise definition: Miscibility is the ability of two liquids, such as refrigerant and oil, to mix into a single liquid phase over specified conditions.
• Expanded explanation: —
• Related term(s): Solubility
• Commonly confused with: —
• Applicable module(s): 3
• EPA 608 / course relevance: Core

Mixed Refrigerant

• Category: Refrigerants, Blends, and Lubricants
• Concise definition: A mixed refrigerant in this context is an unintended combination of refrigerants rather than a properly manufactured refrigerant blend with a defined designation and composition.
• Expanded explanation: —
• Related term(s): Refrigerant
• Commonly confused with: —
• Applicable module(s): 3
• EPA 608 / course relevance: Core

Moisture Indicator

• Category: Type II
• Concise definition: A moisture indicator is a chemical indicator, often integrated into a liquid-line sight glass, that changes color according to moisture condition. Color interpretation must follow the manufacturer legend.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 3, 4, 8
• EPA 608 / course relevance: Core, Type II

Molecular Oxygen

• Category: Safety
• Concise definition: Molecular oxygen is the ordinary two-atom form of oxygen written as $O_2$.
• Expanded explanation: —
• Related term(s): Oxygen
• Commonly confused with: —
• Applicable module(s): 2
• EPA 608 / course relevance: Core

Montreal Protocol

• Category: Regulatory and Environmental
• Concise definition: The Montreal Protocol is the international agreement that controls the production and consumption of ozone-depleting substances and, through the Kigali Amendment, phases down HFCs.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 2
• EPA 608 / course relevance: Core

Motor Vehicle Air Conditioner (MVAC)

• Category: General HVAC/R and Service
• Concise definition: A motor-vehicle air conditioner (MVAC) is mechanical vapor-compression refrigeration equipment used to cool the driver’s or passenger’s compartment of a motor vehicle.
• Expanded explanation: MVAC service is addressed through Section 609 rather than ordinary Type II stationary-equipment service.
• Related term(s): Stationary Refrigeration and Air Conditioning
• Commonly confused with: Refrigerated-Cargo System
• Applicable module(s): 1, 7, 8
• EPA 608 / course relevance: Core, Type I, Type II
• Alias / shorthand: Motor Vehicle Air Conditioner, Motor-Vehicle Air Conditioner

MSDS

• Category: General HVAC/R and Service
• Concise definition: Material Safety Data Sheet, the older term commonly found in older HVAC and refrigeration references. Current OSHA Hazard Communication terminology is Safety Data Sheet (SDS).
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 6
• EPA 608 / course relevance: Core

MVAC-Like Appliance

• Category: General HVAC/R and Service
• Concise definition: A mechanical vapor-compression, open-drive-compressor appliance with a full charge of 20 lb or less used to cool the driver or passenger compartment of off-road vehicles or equipment; the Section 608 definition excludes R-22 appliances.
• Expanded explanation: Qualifying MVAC-like appliances are a boundary case between Section 608 Type II and Section 609 pathways.
• Related term(s): Appliance
• Commonly confused with: Motor Vehicle Air Conditioner (MVAC)
• Applicable module(s): 1, 7, 8
• EPA 608 / course relevance: Core, Type I, Type II

N

Nameplate Charge

• Category: Type I
• Concise definition: The refrigerant quantity identified by the equipment manufacturer on the appliance nameplate or product information. It is useful for classification, but charge quantity alone does not establish Type I status.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: Full Charge
• Applicable module(s): 7
• EPA 608 / course relevance: Type I

National Recycling and Emission Reduction Program

• Category: Regulatory and Environmental
• Concise definition: The National Recycling and Emission Reduction Program is EPA’s refrigerant-management program established under Section 608.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 1
• EPA 608 / course relevance: Core

Near-Azeotropic Blend

• Category: Refrigerants, Blends, and Lubricants
• Concise definition: A near-azeotropic blend is a zeotropic blend with very small temperature glide. It remains part of the zeotropic category.
• Expanded explanation: —
• Related term(s): Blend
• Commonly confused with: —
• Applicable module(s): 3
• EPA 608 / course relevance: Core

Negative Gauge Pressure

• Category: Service Tools and Connections
• Concise definition: Negative gauge pressure means the local absolute pressure is below atmospheric pressure. In HVAC service this condition is commonly described as operation under vacuum.
• Expanded explanation: —
• Related term(s): Gauge Pressure
• Commonly confused with: —
• Applicable module(s): 9
• EPA 608 / course relevance: Type III

Nitrogen Break

• Category: Recovery and Evacuation
• Concise definition: A nitrogen break is the controlled introduction of dry nitrogen into an evacuated refrigeration system as part of a dehydration procedure.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 5
• EPA 608 / course relevance: Core

Nitrogen Purge

• Category: General HVAC/R and Service
• Concise definition: A controlled low-flow use of nitrogen to sweep a line or tubing, such as during a manufacturer-approved brazing procedure. It is not the same as a pressure test.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 6
• EPA 608 / course relevance: Core

Non-Exempt Substitute

• Category: Refrigerants, Blends, and Lubricants
• Concise definition: A non-exempt substitute is a refrigerant substitute that has not been exempted by EPA for the applicable end use and therefore remains subject to the venting prohibition.
• Expanded explanation: —
• Related term(s): Exempt Substitute
• Commonly confused with: —
• Applicable module(s): 2
• EPA 608 / course relevance: Core

Non-Major Repair

• Category: General HVAC/R and Service
• Concise definition: A non-major repair is maintenance, service, or repair that does not meet the regulatory definition of major work. Non-major status alone does not automatically create the special 0-psig exception; all conditions of § 82.156(a)(1) must be satisfied.
• Expanded explanation: —
• Related term(s): Non-Major Work
• Commonly confused with: Major Maintenance, Service, or Repair
• Applicable module(s): 8, 9
• EPA 608 / course relevance: Type II, Type III

Non-Major Work

• Category: General HVAC/R and Service
• Concise definition: For purposes of this course, non-major work means maintenance, service, or repair that does not meet the current federal definition of major maintenance, service, or repair. The fact that work is non-major does not by itself eliminate recovery requirements.
• Expanded explanation: The complete conditions of the applicable exception must still be satisfied.
• Related term(s): Non-Major Repair
• Commonly confused with: —
• Applicable module(s): 5
• EPA 608 / course relevance: Core

Noncondensable

• Category: General HVAC/R and Service
• Concise definition: A noncondensable is a gas, commonly air, that does not condense under the normal condenser conditions of the refrigeration system and can contribute to elevated head pressure and reduced performance.
• Expanded explanation: —
• Related term(s): Noncondensable Gas
• Commonly confused with: Water Vapor
• Applicable module(s): 4, 5, 7, 8, 9
• EPA 608 / course relevance: Core, Type I, Type II, Type III

Noncondensable Gas

• Category: General HVAC/R and Service
• Concise definition: A noncondensable gas is a gas that does not condense under the normal condenser operating conditions of the refrigeration system.
• Expanded explanation: —
• Related term(s): Noncondensable
• Commonly confused with: —
• Applicable module(s): 3
• EPA 608 / course relevance: Core

Nonfunctional Compressor

• Category: Refrigeration Cycle and Thermodynamics
• Concise definition: An appliance compressor that cannot operate as part of the recovery procedure. For recovery equipment manufactured on or after November 15, 1993, the applicable percentage-recovery requirement is 80%.
• Expanded explanation: —
• Related term(s): Functional Compressor
• Commonly confused with: Functional Compressor
• Applicable module(s): 7
• EPA 608 / course relevance: Type I

Nonpressurized Recovery Container

• Category: Recovery and Evacuation
• Concise definition: The refrigerant-collection container used in the special Type I system-dependent recovery example involving a vacuum pump. It is not the same concept as the pressurized recovery cylinder commonly used with self-contained recovery equipment.
• Expanded explanation: Use only the container specified for the certified recovery arrangement.
• Related term(s): Passive Recovery
• Commonly confused with: —
• Applicable module(s): 7
• EPA 608 / course relevance: Type I

Normal Operation

• Category: General HVAC/R and Service
• Concise definition: Normal operation is ordinary functioning of equipment rather than maintenance, service, repair, or disposal. Emissions during normal operation are treated separately from knowing service venting.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 2
• EPA 608 / course relevance: Core

O

Occupational Exposure Limit (OEL)

• Category: Safety
• Concise definition: A numerical concentration used in occupational-health evaluation. Standard 34 uses occupational-exposure and toxicity information in the safety-classification framework. An OEL is not the same thing as the A/B safety letter.
• Expanded explanation: —
• Related term(s): Refrigerant Concentration Limit (RCL)
• Commonly confused with: —
• Applicable module(s): 6
• EPA 608 / course relevance: Core

ODP

• Category: Refrigerants, Blends, and Lubricants
• Concise definition: Ozone-depletion potential; a relative index of a substance’s ability to damage stratospheric ozone.
• Expanded explanation: ODP addresses ozone impact and must not be confused with climate impact, pressure class, toxicity, or flammability.
• Related term(s): Ozone-Depletion Potential; Ozone-Depleting Substance
• Commonly confused with: GWP
• Applicable module(s): 2, 10, 11
• EPA 608 / course relevance: Core

Oil Foaming

• Category: Type III
• Concise definition: Oil foaming is the formation of many refrigerant vapor bubbles in oil when dissolved refrigerant boils out rapidly, often after a sudden pressure reduction.
• Expanded explanation: —
• Related term(s): Oil System
• Commonly confused with: —
• Applicable module(s): 9
• EPA 608 / course relevance: Type III

Oil Heater

• Category: Refrigeration Cycle and Thermodynamics
• Concise definition: An oil heater is an equipment heater used on applicable compressor-oil systems to maintain or raise oil temperature according to manufacturer requirements.
• Expanded explanation: —
• Related term(s): Defrost Heater
• Commonly confused with: —
• Applicable module(s): 9
• EPA 608 / course relevance: Type III

Oil Reservoir / Sump

• Category: Type III
• Concise definition: The oil reservoir or oil sump stores lubricating oil used by a conventional compressor lubrication system.
• Expanded explanation: —
• Related term(s): Oil System
• Commonly confused with: —
• Applicable module(s): 9
• EPA 608 / course relevance: Type III

Oil System

• Category: Type III
• Concise definition: An oil system supplies, conditions, filters, heats/cools, and returns lubricating oil for applicable centrifugal-compressor bearing and drive components. Exact components vary by design.
• Expanded explanation: —
• Related term(s): Oil Foaming
• Commonly confused with: —
• Applicable module(s): 9
• EPA 608 / course relevance: Type III

Oil Trace

• Category: General HVAC/R and Service
• Concise definition: Oil residue found near a refrigerant-containing component or connection that may indicate a leakage path. An oil trace is a clue, not proof of an active leak.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 6
• EPA 608 / course relevance: Core

Open-Drive Compressor

• Category: Refrigeration Cycle and Thermodynamics
• Concise definition: An open-drive compressor has a shaft extending through the compressor housing to an external drive. The rotating shaft seal is a potential refrigerant leak location.
• Expanded explanation: —
• Related term(s): Compressor
• Commonly confused with: —
• Applicable module(s): 6, 8
• EPA 608 / course relevance: Core, Type II

Open-Drive Shaft Seal

• Category: Type III
• Concise definition: An open-drive shaft seal seals the location where a rotating compressor shaft passes through the refrigerant-containing compressor housing. It is a classic leak-prone location on open-drive low-pressure systems.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 9
• EPA 608 / course relevance: Type III

Opening an Appliance

• Category: General HVAC/R and Service
• Concise definition: Maintenance, service, repair, or disposal that would release refrigerant from the appliance to the atmosphere.
• Expanded explanation: Connecting or disconnecting hoses and gauges to measure pressure, add refrigerant, or recover refrigerant is not defined as opening an appliance, although those activities generally still require technician certification.
• Related term(s): Appliance
• Commonly confused with: —
• Applicable module(s): 1, 5
• EPA 608 / course relevance: Core

Operating Compressor

• Category: Refrigeration Cycle and Thermodynamics
• Concise definition: An appliance compressor capable of running and moving refrigerant during the recovery procedure.
• Expanded explanation: —
• Related term(s): Compressor
• Commonly confused with: Failed Compressor
• Applicable module(s): 7
• EPA 608 / course relevance: Type I

OSHA

• Category: Safety
• Concise definition: Occupational Safety and Health Administration, the federal agency responsible for workplace safety and health requirements.
• Expanded explanation: OSHA concepts relevant to the course include confined spaces, respiratory protection, hazard communication, and workplace exposure controls.
• Related term(s): Confined Space; PPE; Safety Data Sheet (SDS)
• Commonly confused with: EPA
• Applicable module(s): 6, 9, 10, 11
• EPA 608 / course relevance: Core; Type III

Outgassing

• Category: General HVAC/R and Service
• Concise definition: Outgassing is the release of gas or vapor from: Oil. Internal surfaces. Hoses. Gaskets. Other system materials as pressure decreases.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 5
• EPA 608 / course relevance: Core

Owner or Operator

• Category: Leak Repair and Recordkeeping
• Concise definition: An owner or operator is the person or entity responsible for the appliance and the compliance duties assigned to its ownership or operation.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 2
• EPA 608 / course relevance: Core

Oxidation Resistance

• Category: General HVAC/R and Service
• Concise definition: Oxidation resistance is the ability of a lubricant to resist oxidation and the formation of harmful degradation products such as sludge.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 3
• EPA 608 / course relevance: Core

Oxygen

• Category: Safety
• Concise definition: A strong oxidizer required for ordinary combustion. Pure oxygen must not be used for refrigeration-system leak or pressure testing.
• Expanded explanation: —
• Related term(s): Molecular Oxygen
• Commonly confused with: —
• Applicable module(s): 6
• EPA 608 / course relevance: Core

Oxygen Deficiency

• Category: Safety
• Concise definition: Under OSHA general-industry definitions: less than 19.5% oxygen by volume
• Expanded explanation: —
• Related term(s): Oxygen
• Commonly confused with: Refrigerant Monitor
• Applicable module(s): 6
• EPA 608 / course relevance: Core

Oxygen Displacement

• Category: Safety
• Concise definition: Reduction of the normal oxygen-containing air in a space because another gas or vapor occupies part of the volume.
• Expanded explanation: —
• Related term(s): Oxygen
• Commonly confused with: —
• Applicable module(s): 6
• EPA 608 / course relevance: Core

Ozone

• Category: Regulatory and Environmental
• Concise definition: Ozone is the three-atom form of oxygen written as $O_3$.
• Expanded explanation: —
• Related term(s): Ozone Layer
• Commonly confused with: —
• Applicable module(s): 2
• EPA 608 / course relevance: Core

Ozone Depletion

• Category: Regulatory and Environmental
• Concise definition: Ozone depletion is a reduction in stratospheric ozone beyond ordinary natural variation as a result of chemical destruction processes.
• Expanded explanation: —
• Related term(s): Ozone
• Commonly confused with: —
• Applicable module(s): 2
• EPA 608 / course relevance: Core

Ozone Layer

• Category: Regulatory and Environmental
• Concise definition: The ozone layer is the region of the stratosphere containing the bulk of atmospheric ozone. It is a broad concentration region rather than a solid or sharply bounded layer.
• Expanded explanation: —
• Related term(s): Ozone
• Commonly confused with: —
• Applicable module(s): 2
• EPA 608 / course relevance: Core

Ozone-Depleting Substance

• Category: Regulatory and Environmental
• Concise definition: An ozone-depleting substance, or ODS, is a compound that contributes to stratospheric ozone depletion by supplying chlorine, bromine, or other ozone-destroying chemistry under atmospheric conditions.
• Expanded explanation: —
• Related term(s): Ozone Depletion
• Commonly confused with: —
• Applicable module(s): 2
• EPA 608 / course relevance: Core

Ozone-Depletion Potential

• Category: Refrigerants, Blends, and Lubricants
• Concise definition: Ozone-depletion potential, or ODP, compares a substance’s ozone-depletion effect with that of the same mass of CFC-11.
• Expanded explanation: —
• Related term(s): Ozone-Depleting Substance; Global-Warming Potential
• Commonly confused with: Global-Warming Potential
• Applicable module(s): 2
• EPA 608 / course relevance: Core

P

P-T Chart

• Category: Pressure, Vacuum, and Measurement
• Concise definition: Pressure-temperature chart; a reference relating a refrigerant’s saturation pressure and saturation temperature.
• Expanded explanation: For zeotropic blends, bubble and dew values must be used correctly for subcooling and superheat rather than treating the blend as a single saturation temperature.
• Related term(s): Pressure-Temperature Chart; Saturation Pressure; Saturation Temperature
• Commonly confused with: Operating pressure by itself
• Applicable module(s): 4, 10, 11
• EPA 608 / course relevance: Core; all Types

Packaged Terminal Air Conditioner

• Category: Type I
• Concise definition: A self-contained room air-conditioning appliance designed for installation through a wall or similar building opening. Whether a particular unit qualifies as a small appliance is determined by the complete regulatory definition.
• Expanded explanation: —
• Related term(s): Room Air Conditioner
• Commonly confused with: —
• Applicable module(s): 7
• EPA 608 / course relevance: Type I

Packaged Terminal Heat Pump

• Category: Refrigeration Cycle and Thermodynamics
• Concise definition: A packaged terminal unit capable of heating by reversing the refrigeration cycle as well as providing cooling. The current small-appliance definition specifically includes packaged terminal air heat pumps among room-air-conditioning equipment.
• Expanded explanation: —
• Related term(s): Latent Heat
• Commonly confused with: —
• Applicable module(s): 7
• EPA 608 / course relevance: Type I

Packing Group

• Category: Disposal, Cylinders, and Shipping
• Concise definition: A transportation classification indicating degree of danger for hazard classes that use packing groups. Many Class 2 gas entries are not assigned a packing group.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 6
• EPA 608 / course relevance: Core

Parallel Compressors

• Category: Refrigeration Cycle and Thermodynamics
• Concise definition: Parallel compressors are two or more compressors connected to common suction and discharge headers so that they serve a common refrigeration system or rack.
• Expanded explanation: —
• Related term(s): Failed Compressor
• Commonly confused with: —
• Applicable module(s): 8
• EPA 608 / course relevance: Type II

Passive Recovery

• Category: Recovery and Evacuation
• Concise definition: Passive recovery is a common study term for a recovery process that depends on the appliance, refrigerant pressure, or system conditions rather than an independent recovery-machine compressor. The current regulatory term is system-dependent recovery equipment.
• Expanded explanation: —
• Related term(s): Active Recovery
• Commonly confused with: —
• Applicable module(s): 5, 7
• EPA 608 / course relevance: Core, Type I

Percentage Recovery

• Category: Recovery and Evacuation
• Concise definition: The fraction of the appliance refrigerant charge removed during recovery. For Type I, the relevant current percentage values are: 80% and: 90% depending on recovery-equipment date and compressor condition.
• Expanded explanation: —
• Related term(s): Active Recovery
• Commonly confused with: —
• Applicable module(s): 7
• EPA 608 / course relevance: Type I

Perfect Vacuum

• Category: Recovery and Evacuation
• Concise definition: A perfect vacuum is the theoretical condition of zero absolute pressure.
• Expanded explanation: —
• Related term(s): Vacuum
• Commonly confused with: —
• Applicable module(s): 4
• EPA 608 / course relevance: Core

Permit-Required Confined Space

• Category: Safety
• Concise definition: A confined space with one or more serious additional hazards, such as a hazardous atmosphere, engulfment hazard, trapping configuration, or other recognized serious hazard.
• Expanded explanation: —
• Related term(s): Confined Space
• Commonly confused with: —
• Applicable module(s): 6
• EPA 608 / course relevance: Core

Personal Protective Equipment (PPE)

• Category: Safety
• Concise definition: Equipment worn to minimize exposure to hazards. Examples include eye protection, gloves, protective clothing, and—where properly required—respiratory protection.
• Expanded explanation: —
• Related term(s): Emergency Equipment Shutdown
• Commonly confused with: —
• Applicable module(s): 6
• EPA 608 / course relevance: Core

Phase

• Category: Refrigeration Cycle and Thermodynamics
• Concise definition: A phase is a physically distinct form of matter. The liquid and vapor forms of a refrigerant are different phases.
• Expanded explanation: —
• Related term(s): Two-Phase Region
• Commonly confused with: —
• Applicable module(s): 3
• EPA 608 / course relevance: Core

Phaseout

• Category: Refrigeration Cycle and Thermodynamics
• Concise definition: A phaseout is a scheduled reduction leading to elimination or near-elimination of a specified controlled activity, such as production or import.
• Expanded explanation: —
• Related term(s): Phase
• Commonly confused with: —
• Applicable module(s): 2
• EPA 608 / course relevance: Core

Phosgene

• Category: General HVAC/R and Service
• Concise definition: A highly toxic chlorine-containing compound that can be produced under some high-temperature decomposition conditions involving chlorine-containing halocarbons. Phosgene is not a universal decomposition product of every refrigerant.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 6
• EPA 608 / course relevance: Core

Photodissociation

• Category: Regulatory and Environmental
• Concise definition: Photodissociation is the breaking of a chemical bond after a molecule absorbs radiation.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 2
• EPA 608 / course relevance: Core

Photolysis

• Category: Regulatory and Environmental
• Concise definition: Photolysis is a light-driven chemical decomposition process. In ozone-depletion chemistry, intense stratospheric UV radiation can photolyze ODS molecules and release reactive halogens.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 2
• EPA 608 / course relevance: Core

Piercing Access Valve

• Category: Type I
• Concise definition: A mechanical access fitting that clamps onto compatible tubing and pierces the tubing wall to create a controlled service connection.
• Expanded explanation: —
• Related term(s): Solderless Access Fitting; Process Stub
• Commonly confused with: —
• Applicable module(s): 7
• EPA 608 / course relevance: Type I

Placard

• Category: Disposal, Cylinders, and Shipping
• Concise definition: A larger hazard-identification display placed on a transport vehicle, freight container, or certain bulk packaging when required.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 6
• EPA 608 / course relevance: Core

Polar Stratospheric Cloud

• Category: Regulatory and Environmental
• Concise definition: A polar stratospheric cloud is a cloud that forms under very cold stratospheric conditions. Reactions on its particle surfaces can convert chlorine reservoir species into forms that become highly reactive when sunlight returns.
• Expanded explanation: —
• Related term(s): Polar Vortex
• Commonly confused with: —
• Applicable module(s): 2
• EPA 608 / course relevance: Core

Polar Vortex

• Category: Regulatory and Environmental
• Concise definition: The polar vortex is a large-scale circulation pattern that can isolate cold polar stratospheric air and support conditions favorable for severe seasonal ozone depletion.
• Expanded explanation: —
• Related term(s): Polar Stratospheric Cloud
• Commonly confused with: —
• Applicable module(s): 2
• EPA 608 / course relevance: Core

Polyalkylene Glycol

• Category: Refrigerants, Blends, and Lubricants
• Concise definition: Polyalkylene glycol (PAG) is a synthetic lubricant widely associated with R-134a mobile air-conditioning applications.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 3
• EPA 608 / course relevance: Core

Polyalphaolefin

• Category: General HVAC/R and Service
• Concise definition: Polyalphaolefin (PAO) is a synthetic hydrocarbon lubricant broadly associated in course study material with R-717 ammonia refrigeration applications.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 3
• EPA 608 / course relevance: Core

Polyolester

• Category: Refrigerants, Blends, and Lubricants
• Concise definition: Polyolester (POE) is a synthetic ester lubricant widely used with HFC and many newer stationary refrigeration applications and is especially sensitive to moisture exposure.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 3
• EPA 608 / course relevance: Core

Positive Gauge Pressure

• Category: Service Tools and Connections
• Concise definition: Positive gauge pressure means the local absolute pressure is greater than atmospheric pressure. A leak at such a location tends to allow refrigerant or gas to move outward.
• Expanded explanation: —
• Related term(s): Gauge Pressure
• Commonly confused with: —
• Applicable module(s): 9
• EPA 608 / course relevance: Type III

PPE

• Category: Safety
• Concise definition: Personal protective equipment used to reduce exposure to workplace hazards.
• Expanded explanation: Examples in refrigerant work include eye protection, chemical-resistant gloves, face protection, and other task-specific equipment selected from the hazard assessment.
• Related term(s): Personal Protective Equipment (PPE); Hazard Assessment
• Commonly confused with: PPE does not replace ventilation or safe procedure
• Applicable module(s): 6, 7, 8, 9, 10, 11
• EPA 608 / course relevance: Core; all Types

Pressure Rating

• Category: Pressure, Vacuum, and Measurement
• Concise definition: The maximum pressure a component is designed, listed, or approved to withstand under specified conditions.
• Expanded explanation: —
• Related term(s): Pressure Rise
• Commonly confused with: —
• Applicable module(s): 6
• EPA 608 / course relevance: Core

Pressure Rebound

• Category: Pressure, Vacuum, and Measurement
• Concise definition: An increase in appliance pressure after recovery flow stops because remaining liquid or refrigerant dissolved in oil absorbs heat and vaporizes.
• Expanded explanation: No fixed Type I waiting time is established in this section; the concept simply warns that a momentary low pressure does not always prove that liquid refrigerant is gone.
• Related term(s): Pressure Rise
• Commonly confused with: Vacuum Decay
• Applicable module(s): 5, 7, 8, 9
• EPA 608 / course relevance: Core, Type I, Type II, Type III

Pressure Regulator

• Category: Service Tools and Connections
• Concise definition: A device that reduces high cylinder pressure to a controlled downstream delivery pressure.
• Expanded explanation: —
• Related term(s): Dry Nitrogen; Downstream Relief Valve
• Commonly confused with: —
• Applicable module(s): 6
• EPA 608 / course relevance: Core

Pressure Rise

• Category: Pressure, Vacuum, and Measurement
• Concise definition: Pressure rise during a standing vacuum test means an increase in absolute pressure, normally observed as an increasing micron value.
• Expanded explanation: —
• Related term(s): Pressure Rating
• Commonly confused with: —
• Applicable module(s): 5
• EPA 608 / course relevance: Core

Pressure-Decay Test

• Category: Recovery and Evacuation
• Concise definition: A pressure-decay test monitors whether pressure remains stable in a closed, pressurized system. It can indicate leakage but does not by itself identify the leak location.
• Expanded explanation: —
• Related term(s): Decay Test
• Commonly confused with: —
• Applicable module(s): 8
• EPA 608 / course relevance: Type II

Pressure-Relief Device

• Category: Safety
• Concise definition: A pressure-relief device protects refrigerant-containing equipment against dangerous overpressure by providing an engineered relief path at specified conditions.
• Expanded explanation: —
• Related term(s): Downstream Relief Valve
• Commonly confused with: —
• Applicable module(s): 8
• EPA 608 / course relevance: Type II

Pressure-Rise Check

• Category: Recovery and Evacuation
• Concise definition: A pressure-rise check is the observation of appliance pressure after the apparent recovery endpoint has been reached and the active recovery process is isolated or stopped according to procedure.
• Expanded explanation: —
• Related term(s): Pressure-Decay Test
• Commonly confused with: —
• Applicable module(s): 8
• EPA 608 / course relevance: Type II

Pressure-Temperature Chart

• Category: Pressure, Vacuum, and Measurement
• Concise definition: A pressure-temperature chart relates refrigerant saturation pressure and temperature. For a zeotropic blend, the chart may provide separate bubble and dew values.
• Expanded explanation: —
• Related term(s): Saturation Pressure; Saturation Temperature
• Commonly confused with: Pressure-Temperature Relationship
• Applicable module(s): 3, 4
• EPA 608 / course relevance: Core

Pressure-Temperature Relationship

• Category: Pressure, Vacuum, and Measurement
• Concise definition: The pressure-temperature relationship describes the fixed relationship between saturation pressure and saturation temperature for a refrigerant at equilibrium. It is commonly represented by a P-T chart.
• Expanded explanation: —
• Related term(s): Pressure-Temperature Chart
• Commonly confused with: Pressure-Temperature Chart
• Applicable module(s): 3, 8
• EPA 608 / course relevance: Core, Type II

Previously Produced Refrigerant

• Category: Refrigerants, Blends, and Lubricants
• Concise definition: Previously produced refrigerant is material lawfully produced or imported before the applicable production or import restriction took effect.
• Expanded explanation: —
• Related term(s): Refrigerant
• Commonly confused with: —
• Applicable module(s): 2
• EPA 608 / course relevance: Core

Prior-Recovery Verification

• Category: Recovery and Evacuation
• Concise definition: Documentation used by a final processor to establish that refrigerant was properly recovered before the appliance reached the final processor.
• Expanded explanation: —
• Related term(s): Signed Verification Statement; Final Disposer
• Commonly confused with: —
• Applicable module(s): 7
• EPA 608 / course relevance: Type I

Process Stub

• Category: Type I
• Concise definition: A length of tubing that provides access to refrigerant inside a small appliance or room air conditioner and can be resealed after service or repair.
• Expanded explanation: A process stub is tubing, not a disposable cylinder or pressure-relief device.
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 5, 7
• EPA 608 / course relevance: Core, Type I

Proctor

• Category: Certification, Examination, and Study
• Concise definition: A proctor is a person or approved monitoring system that supervises an examination, verifies identity, and protects test security.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 1
• EPA 608 / course relevance: Core

Production

• Category: Regulatory and Environmental
• Concise definition: Under the Montreal Protocol, production is a defined national accounting quantity for controlled substances. Specified destruction and feedstock uses are excluded, and recycled or reused material is not counted as new production.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 2
• EPA 608 / course relevance: Core

Proper Shipping Name

• Category: Disposal, Cylinders, and Shipping
• Concise definition: The transportation name assigned by the Hazardous Materials Table for describing the hazardous material.
• Expanded explanation: —
• Related term(s): Shipping Paper
• Commonly confused with: —
• Applicable module(s): 6
• EPA 608 / course relevance: Core

Proposed Rule

• Category: Regulatory and Environmental
• Concise definition: A proposed rule is an agency proposal that has not become a final effective requirement.
• Expanded explanation: —
• Related term(s): Scheduled Rule
• Commonly confused with: —
• Applicable module(s): 2
• EPA 608 / course relevance: Core

psia

• Category: Pressure, Vacuum, and Measurement
• Concise definition: psia means pounds per square inch absolute.
• Expanded explanation: —
• Related term(s): psig
• Commonly confused with: psig
• Applicable module(s): 4
• EPA 608 / course relevance: Core

psig

• Category: Pressure, Vacuum, and Measurement
• Concise definition: psig means pounds per square inch gauge.
• Expanded explanation: —
• Related term(s): psia
• Commonly confused with: psia
• Applicable module(s): 4
• EPA 608 / course relevance: Core

Pump-Out Unit

• Category: Recovery and Evacuation
• Concise definition: A pump-out unit is recovery equipment associated with an appliance that can be used to transfer refrigerant for service or repair.
• Expanded explanation: The specific Section 608 exception discussed in this section applies when system-dependent equipment is permanently attached to the appliance as a pump-out unit.
• Related term(s): Vacuum Pump
• Commonly confused with: —
• Applicable module(s): 5, 8
• EPA 608 / course relevance: Core, Type II

Purchaser

• Category: Regulatory and Environmental
• Concise definition: The purchaser is the certified person, qualifying employer, manufacturer, reseller, or other allowed buyer responsible for the transaction.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 2
• EPA 608 / course relevance: Core

Pure Refrigerant

• Category: Refrigerants, Blends, and Lubricants
• Concise definition: A pure refrigerant is a refrigerant consisting of one chemical compound.
• Expanded explanation: —
• Related term(s): Refrigerant
• Commonly confused with: Blend
• Applicable module(s): 3
• EPA 608 / course relevance: Core

Purge / Self-Clear

• Category: Type II
• Concise definition: A purge or self-clear function is a manufacturer-designed process for removing residual refrigerant from the recovery machine’s internal passages and directing it to the recovery container. It is not permission to vent refrigerant.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 8
• EPA 608 / course relevance: Type II

Purge Discharge

• Category: Refrigeration Cycle and Thermodynamics
• Concise definition: Purge discharge is the gas stream leaving the noncondensable-removal portion of the purge process after refrigerant separation. It should not be understood as an intentional refrigerant-venting stream.
• Expanded explanation: —
• Related term(s): Purge Unit; Noncondensable Gas
• Commonly confused with: —
• Applicable module(s): 9
• EPA 608 / course relevance: Type III

Purge Unit

• Category: Type III
• Concise definition: A purge unit is equipment used on applicable low-pressure chillers to remove accumulated noncondensable gases while minimizing refrigerant loss. Its operation is developed in Section 9.3.
• Expanded explanation: —
• Related term(s): Noncondensable Gas; Air Infiltration
• Commonly confused with: Recovery Machine
• Applicable module(s): 9
• EPA 608 / course relevance: Type III

Purging a Hose

• Category: Recovery and Evacuation
• Concise definition: Purging or clearing a hose means removing unwanted air or gas from the hose before the hose contents are introduced into the intended refrigeration circuit or recovery stream. The procedure must minimize refrigerant release.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 4
• EPA 608 / course relevance: Core

Push-Pull Recovery

• Category: Recovery and Evacuation
• Concise definition: Push-pull recovery is a specialized bulk-liquid transfer method in which the recovery machine establishes a pressure difference that causes liquid refrigerant to flow directly from the appliance to the recovery cylinder.
• Expanded explanation: —
• Related term(s): Passive Recovery
• Commonly confused with: —
• Applicable module(s): 5
• EPA 608 / course relevance: Core

Q

Qualifying Contract

• Category: Type I
• Concise definition: A contract between the final processor and an appropriate regular commercial supplier establishing responsibility for proper refrigerant recovery or verification before delivery.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 7
• EPA 608 / course relevance: Type I

R

Receiver

• Category: Refrigeration Cycle and Thermodynamics
• Concise definition: A receiver is a high-side vessel normally located downstream of the condenser that stores and manages high-pressure liquid refrigerant.
• Expanded explanation: —
• Related term(s): Liquid Receiver
• Commonly confused with: Recovery Cylinder
• Applicable module(s): 8
• EPA 608 / course relevance: Type II

Reclaim

• Category: Recovery and Evacuation
• Concise definition: To reprocess recovered refrigerant to all applicable purity specifications in Appendix A to 40 CFR Part 82, Subpart F and verify compliance using the prescribed analytical methodology.
• Expanded explanation: Reclamation is a higher purification and verification level than recycling.
• Related term(s): Recover; Recycle
• Commonly confused with: Recycle
• Applicable module(s): 2, 5
• EPA 608 / course relevance: Core

Reclaimed Refrigerant

• Category: Recovery and Evacuation
• Concise definition: Reclaimed refrigerant is used refrigerant that has been reprocessed and analytically verified to meet the applicable purity specifications required for reclamation.
• Expanded explanation: —
• Related term(s): Recycled Refrigerant
• Commonly confused with: Recycled Refrigerant
• Applicable module(s): 2, 5
• EPA 608 / course relevance: Core

Reclamation

• Category: Recovery and Evacuation
• Concise definition: Reprocessing recovered refrigerant to the applicable purity specification and verifying that specification using the prescribed analytical method.
• Expanded explanation: Reclamation is required in situations where recovered refrigerant is transferred or sold to a new owner unless a regulatory exception or route applies.
• Related term(s): Reclaim; Reclaimed Refrigerant; AHRI Standard 700
• Commonly confused with: Recycling
• Applicable module(s): 5, 10, 11
• EPA 608 / course relevance: Core

Record Retention Period

• Category: Leak Repair and Recordkeeping
• Concise definition: A record retention period is the time during which a required record must be preserved and made available.
• Expanded explanation: —
• Related term(s): Falsified Record
• Commonly confused with: —
• Applicable module(s): 2
• EPA 608 / course relevance: Core

Recover

• Category: Recovery and Evacuation
• Concise definition: To remove refrigerant in any condition from an appliance and store it in an external container without necessarily testing or processing it.
• Expanded explanation: Recovery describes removal and storage; it does not by itself mean the refrigerant has been recycled or reclaimed.
• Related term(s): Recycle; Reclaim
• Commonly confused with: Evacuation
• Applicable module(s): 2, 5
• EPA 608 / course relevance: Core

Recovered Refrigerant

• Category: Recovery and Evacuation
• Concise definition: Recovered refrigerant is refrigerant removed from an appliance and stored externally. Recovery by itself does not establish purity.
• Expanded explanation: —
• Related term(s): Recycled Refrigerant
• Commonly confused with: —
• Applicable module(s): 5
• EPA 608 / course relevance: Core

Recovery

• Category: Recovery and Evacuation
• Concise definition: The process of removing refrigerant from an appliance and storing it in an external container.
• Expanded explanation: Recovery is the noun form of recover. It does not by itself mean the refrigerant has been cleaned for reuse or processed to reclamation purity.
• Related term(s): Recover; Recovery Equipment; Recovery Cylinder
• Commonly confused with: Recycling; Reclamation
• Applicable module(s): 5, 7, 8, 9, 10, 11
• EPA 608 / course relevance: Core; Type I; Type II; Type III

Recovery Access Point

• Category: Recovery and Evacuation
• Concise definition: A recovery access point is a service port or valve connection through which refrigerant can be removed from an appliance using approved recovery equipment.
• Expanded explanation: —
• Related term(s): Recovery Endpoint
• Commonly confused with: —
• Applicable module(s): 8
• EPA 608 / course relevance: Type II

Recovery Before Disposal

• Category: Recovery and Evacuation
• Concise definition: Removal of refrigerant according to the applicable EPA requirements before an appliance is dismantled or finally discarded.
• Expanded explanation: —
• Related term(s): Disposal-Recovery Person
• Commonly confused with: —
• Applicable module(s): 6
• EPA 608 / course relevance: Core

Recovery Completion

• Category: Recovery and Evacuation
• Concise definition: Recovery completion means that the applicable refrigerant-removal requirement has been satisfied and remaining internal refrigerant sources have been properly evaluated according to current requirements and manufacturer procedures.
• Expanded explanation: —
• Related term(s): Recovery Compressor
• Commonly confused with: Dehydration
• Applicable module(s): 9
• EPA 608 / course relevance: Type III

Recovery Compressor

• Category: Recovery and Evacuation
• Concise definition: A recovery compressor is the compressor inside a self-contained recovery machine that draws refrigerant vapor from the chiller and raises its pressure for heat rejection and transfer to the recovery vessel.
• Expanded explanation: —
• Related term(s): Independent Recovery Compressor
• Commonly confused with: —
• Applicable module(s): 9
• EPA 608 / course relevance: Type III

Recovery Cylinder

• Category: Disposal, Cylinders, and Shipping
• Concise definition: A recovery cylinder is a refillable cylinder designed and approved to receive recovered refrigerant. Detailed cylinder markings and fill rules are covered in Section 5.6.
• Expanded explanation: —
• Related term(s): Available Cylinder Capacity; DOT Specification Cylinder
• Commonly confused with: Receiver
• Applicable module(s): 5, 7
• EPA 608 / course relevance: Core, Type I

Recovery Endpoint

• Category: Recovery and Evacuation
• Concise definition: The required refrigerant-removal condition that must be reached under the applicable Section 608 rule. For Type I small appliances, the current pathways include percentage-recovery requirements and the 4 in. Hg vacuum alternative described in Section 7.3.
• Expanded explanation: —
• Related term(s): Recovery Machine
• Commonly confused with: Dehydration
• Applicable module(s): 7
• EPA 608 / course relevance: Type I

Recovery Equipment Certification

• Category: Recovery and Evacuation
• Concise definition: Third-party or legacy compliance showing that recovery/recycling equipment meets the applicable federal performance requirements for its intended appliance category.
• Expanded explanation: —
• Related term(s): Certified Refrigerant Recovery or Recycling Equipment; Approved Equipment Testing Organization
• Commonly confused with: —
• Applicable module(s): 7
• EPA 608 / course relevance: Type I

Recovery Equipment Manufacture Date

• Category: Recovery and Evacuation
• Concise definition: The date the recovery or recycling equipment was manufactured. The key regulatory dividing date for Type I recovery is: November 15, 1993
• Expanded explanation: —
• Related term(s): Recovery Equipment Certification
• Commonly confused with: —
• Applicable module(s): 7
• EPA 608 / course relevance: Type I

Recovery Machine

• Category: Recovery and Evacuation
• Concise definition: A recovery machine is equipment used to remove refrigerant from an appliance for storage in an external container or other permitted location.
• Expanded explanation: —
• Related term(s): Recovery-Machine Inlet
• Commonly confused with: Purge Unit
• Applicable module(s): 5
• EPA 608 / course relevance: Core

Recovery Rate

• Category: Recovery and Evacuation
• Concise definition: Recovery rate is the rate at which refrigerant mass is removed from an appliance. Recovery rate varies with refrigerant state, equipment, temperature, hose configuration, and restrictions.
• Expanded explanation: —
• Related term(s): Recovery Machine
• Commonly confused with: —
• Applicable module(s): 5
• EPA 608 / course relevance: Core

Recovery-Machine Condenser

• Category: Recovery and Evacuation
• Concise definition: The condenser in a recovery machine removes heat from compressed refrigerant vapor so the refrigerant can condense and be transferred efficiently to the recovery vessel.
• Expanded explanation: Water-cooled condenser arrangements are commonly emphasized in traditional Type III examination preparation.
• Related term(s): Recovery Machine
• Commonly confused with: —
• Applicable module(s): 9
• EPA 608 / course relevance: Type III

Recovery-Machine Inlet

• Category: Recovery and Evacuation
• Concise definition: The recovery-machine inlet is the connection through which refrigerant enters a self-contained recovery machine from the appliance or manifold service path.
• Expanded explanation: —
• Related term(s): Recovery Machine
• Commonly confused with: —
• Applicable module(s): 5, 7, 8
• EPA 608 / course relevance: Core, Type I, Type II

Recovery-Machine Outlet

• Category: Recovery and Evacuation
• Concise definition: The recovery-machine outlet is the connection through which recovered refrigerant leaves the machine and flows toward the recovery cylinder.
• Expanded explanation: —
• Related term(s): Recovery Machine
• Commonly confused with: —
• Applicable module(s): 5, 7, 8
• EPA 608 / course relevance: Core, Type I, Type II

Recovery-Machine Receiver

• Category: Recovery and Evacuation
• Concise definition: A recovery-machine receiver or internal reservoir is an internal refrigerant-holding component found in some recovery/recycling equipment. It is different from the receiver in the appliance being serviced.
• Expanded explanation: —
• Related term(s): Recovery Machine
• Commonly confused with: —
• Applicable module(s): 8
• EPA 608 / course relevance: Type II

Recycle

• Category: Recovery and Evacuation
• Concise definition: To extract refrigerant from an appliance and clean it for reuse in equipment of the same owner without meeting all reclamation requirements.
• Expanded explanation: Typical recycling processes reduce oil, moisture, acidity, and particulate contamination; recycling is not the same as reclamation.
• Related term(s): Recover; Reclaim
• Commonly confused with: Reclaim
• Applicable module(s): 2, 5
• EPA 608 / course relevance: Core

Recycled Refrigerant

• Category: Recovery and Evacuation
• Concise definition: Recycled refrigerant is refrigerant that has been extracted and cleaned for permitted same-owner reuse without full reclamation processing and verification.
• Expanded explanation: —
• Related term(s): Reclaimed Refrigerant
• Commonly confused with: Reclaimed Refrigerant
• Applicable module(s): 5
• EPA 608 / course relevance: Core

Recycling

• Category: Recovery and Evacuation
• Concise definition: Cleaning recovered refrigerant for permitted reuse without meeting all reclamation requirements.
• Expanded explanation: Under the Section 608 stationary-appliance framework, recycling is distinct from reclamation and has specific reuse limitations.
• Related term(s): Recycle; Recycled Refrigerant
• Commonly confused with: Reclamation
• Applicable module(s): 5, 10, 11
• EPA 608 / course relevance: Core

Refrigerant

• Category: Refrigerants, Blends, and Lubricants
• Concise definition: For Section 608 purposes, a substance, blend, or mixture consisting in part or whole of a class I or class II ozone-depleting substance or a substitute, used for heat transfer and providing a cooling effect.
• Expanded explanation: The course also uses the broader HVAC/R sense when discussing thermodynamic behavior and equipment service.
• Related term(s): Used Refrigerant
• Commonly confused with: —
• Applicable module(s): 1, 3
• EPA 608 / course relevance: Core

Refrigerant Analyzer

• Category: Service Tools and Connections
• Concise definition: A refrigerant analyzer is an instrument used to help identify a refrigerant sample and, depending on the instrument, evaluate its composition or purity.
• Expanded explanation: —
• Related term(s): Refrigerant Detector
• Commonly confused with: —
• Applicable module(s): 3
• EPA 608 / course relevance: Core

Refrigerant Circuit

• Category: Refrigerants, Blends, and Lubricants
• Concise definition: The parts of an appliance that are normally connected to one another, or separated only by internal valves, and are designed to contain refrigerant.
• Expanded explanation: Whether an activity could violate the integrity of this circuit is central to the Section 608 technician definition.
• Related term(s): Refrigerant
• Commonly confused with: —
• Applicable module(s): 1
• EPA 608 / course relevance: Core

Refrigerant Concentration Limit (RCL)

• Category: Safety
• Concise definition: A refrigerant-specific concentration limit established within Standard 34 and used by related refrigeration safety requirements. An RCL is not a universal value shared by all refrigerants in the same safety group.
• Expanded explanation: —
• Related term(s): Trapped Refrigerant
• Commonly confused with: —
• Applicable module(s): 6
• EPA 608 / course relevance: Core

Refrigerant Designation (R-number)

• Category: Refrigerants, Blends, and Lubricants
• Concise definition: The standardized R-number identifier used to designate refrigerants, such as R-22, R-134a, or R-410A.
• Expanded explanation: The designation identifies the refrigerant but does not by itself state its EPA certification type, pressure class, safety class, ODP, or GWP.
• Related term(s): ANSI/ASHRAE Standard 34; Refrigerant Identification
• Commonly confused with: EPA certification type
• Applicable module(s): 3, 6, 8, 9, 10, 11
• EPA 608 / course relevance: Core; all Types

Refrigerant Detector

• Category: Service Tools and Connections
• Concise definition: A fixed or portable sensing device that responds to the presence or concentration of a target refrigerant. In machinery-room applications, the term commonly refers to a fixed safety detector.
• Expanded explanation: —
• Related term(s): Refrigerant Analyzer
• Commonly confused with: —
• Applicable module(s): 6
• EPA 608 / course relevance: Core

Refrigerant Heel

• Category: Recovery and Evacuation
• Concise definition: The refrigerant remaining in a container after normal withdrawal or use has removed most of the usable contents.
• Expanded explanation: —
• Related term(s): Recycled Refrigerant
• Commonly confused with: —
• Applicable module(s): 6
• EPA 608 / course relevance: Core

Refrigerant Identification

• Category: Refrigerants, Blends, and Lubricants
• Concise definition: The process of determining what refrigerant is present using information such as the appliance nameplate, manufacturer data, cylinder label, P-T behavior, and refrigerant analyzer.
• Expanded explanation: —
• Related term(s): Refrigerant
• Commonly confused with: —
• Applicable module(s): 3, 7
• EPA 608 / course relevance: Core, Type I

Refrigerant Migration

• Category: Refrigerants, Blends, and Lubricants
• Concise definition: Movement of refrigerant from one portion of the appliance to another because of: Pressure difference. Temperature difference. Vaporization and condensation. Gravity. Recovery-induced pressure reduction.
• Expanded explanation: —
• Related term(s): Refrigerant
• Commonly confused with: —
• Applicable module(s): 7, 8
• EPA 608 / course relevance: Type I, Type II

Refrigerant Monitor

• Category: Refrigerants, Blends, and Lubricants
• Concise definition: A commonly used field term for a device or system that continuously or periodically monitors refrigerant concentration. The applicable code may use the more specific term refrigerant detector.
• Expanded explanation: —
• Related term(s): Refrigerant Detector; Oxygen Deficiency
• Commonly confused with: Oxygen Deficiency
• Applicable module(s): 6, 9
• EPA 608 / course relevance: Core, Type III

Refrigerant Side

• Category: Refrigerants, Blends, and Lubricants
• Concise definition: The side of the heat exchanger containing refrigerant.
• Expanded explanation: —
• Related term(s): Refrigerant
• Commonly confused with: —
• Applicable module(s): 9
• EPA 608 / course relevance: Type III

Refrigerated-Cargo System

• Category: Type I
• Concise definition: A refrigerated-cargo system cools cargo rather than the driver’s or passenger’s compartment. Hermetically sealed cargo-refrigeration systems on motor vehicles are excluded from the MVAC definition.
• Expanded explanation: —
• Related term(s): Field-Connected Split System
• Commonly confused with: Motor Vehicle Air Conditioner (MVAC)
• Applicable module(s): 1, 7
• EPA 608 / course relevance: Core, Type I
• Alias / shorthand: Refrigerated Cargo

Refrigeration Cycle

• Category: Refrigeration Cycle and Thermodynamics
• Concise definition: A refrigeration cycle is a repeating thermodynamic process that transfers heat from a lower-temperature region to a higher-temperature region through refrigerant circulation and energy input.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 4
• EPA 608 / course relevance: Core

Regulated Substance

• Category: Refrigerants, Blends, and Lubricants
• Concise definition: Under the AIM Act framework, a regulated substance is an HFC listed as regulated under the Act and Part 84.
• Expanded explanation: —
• Related term(s): Class I Substance
• Commonly confused with: —
• Applicable module(s): 8
• EPA 608 / course relevance: Type II

Remote Proctoring

• Category: Certification, Examination, and Study
• Concise definition: Remote proctoring uses a camera, microphone, screen recording, or related technology to supervise an examination away from a physical test center.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 1
• EPA 608 / course relevance: Core

Requalification

• Category: Disposal, Cylinders, and Shipping
• Concise definition: Periodic examination/testing required to keep certain refillable cylinders qualified for continued hazardous-material service.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 6
• EPA 608 / course relevance: Core

Resale

• Category: Regulatory and Environmental
• Concise definition: Resale is a purchase made for eventual lawful sale to certified technicians, qualifying employers, appliance manufacturers, or other allowed purchasers.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 2
• EPA 608 / course relevance: Core

Reseal

• Category: Type I
• Concise definition: To restore the refrigerant circuit to a closed condition after temporary service access has been removed.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 7
• EPA 608 / course relevance: Type I

Reservoir Species

• Category: Regulatory and Environmental
• Concise definition: A reservoir species is a comparatively less reactive compound that temporarily stores chlorine or bromine and reduces its immediate availability for ozone-destruction reactions.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 2
• EPA 608 / course relevance: Core

Restricted Access

• Category: General HVAC/R and Service
• Concise definition: A requirement that limits machinery-room entry to authorized personnel.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 6
• EPA 608 / course relevance: Core

Retirement

• Category: Type II
• Concise definition: Retirement means taking an appliance permanently out of service under the applicable regulatory plan.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 8
• EPA 608 / course relevance: Type II

Retrieval Practice

• Category: Certification, Examination, and Study
• Concise definition: Retrieval practice requires the student to recall and apply knowledge rather than reread it passively.
• Expanded explanation: —
• Related term(s): Interleaved Practice
• Commonly confused with: —
• Applicable module(s): 1
• EPA 608 / course relevance: Core

Retrofit

• Category: Type II
• Concise definition: A retrofit is the conversion of existing equipment to use a different approved refrigerant together with any required component, lubricant, control, safety, or labeling changes.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 3, 8
• EPA 608 / course relevance: Core, Type II

Retrofit Label

• Category: General HVAC/R and Service
• Concise definition: A retrofit label records that equipment has been converted from its original refrigerant to another approved refrigerant and identifies relevant service information.
• Expanded explanation: —
• Related term(s): Hazard Label
• Commonly confused with: —
• Applicable module(s): 3
• EPA 608 / course relevance: Core

Room Air Conditioner

• Category: Type I
• Concise definition: A factory-completed appliance intended to condition a room or localized space. The current definition includes examples such as: Window air conditioners. Portable air conditioners. Packaged terminal air heat pumps.
• Expanded explanation: —
• Related term(s): Packaged Terminal Air Conditioner
• Commonly confused with: —
• Applicable module(s): 7
• EPA 608 / course relevance: Type I

Rupture Disc

• Category: Safety
• Concise definition: A rupture disc is a non-reclosing pressure-relief device designed to open at its rated condition to protect equipment against excessive pressure. Do not assume one universal rating for every chiller.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 9
• EPA 608 / course relevance: Type III

S

Safety Classification

• Category: Safety
• Concise definition: A refrigerant safety classification identifies toxicity and flammability characteristics, commonly using designations such as A1, A2L, A2, and A3.
• Expanded explanation: —
• Related term(s): Safety Group
• Commonly confused with: —
• Applicable module(s): 3
• EPA 608 / course relevance: Core

Safety Data Sheet (SDS)

• Category: Safety
• Concise definition: A standardized document containing information about a hazardous chemical’s identity, hazards, first-aid measures, handling and storage, exposure controls, PPE, stability, and other safety information.
• Expanded explanation: —
• Related term(s): Safety Classification
• Commonly confused with: —
• Applicable module(s): 6
• EPA 608 / course relevance: Core

Safety Group

• Category: Safety
• Concise definition: The combined toxicity and flammability classification assigned to a refrigerant. Examples include: A1. A2L. A2. A3. B1. B2L.
• Expanded explanation: —
• Related term(s): Safety Classification
• Commonly confused with: —
• Applicable module(s): 6
• EPA 608 / course relevance: Core

Same-Owner Reuse

• Category: General HVAC/R and Service
• Concise definition: Same-owner reuse is reuse of recovered or recycled refrigerant in the same appliance or another suitable appliance owned by the same person without triggering the reclamation requirement solely because of that reuse.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 5
• EPA 608 / course relevance: Core

Saturated Liquid

• Category: Refrigeration Cycle and Thermodynamics
• Concise definition: A saturated liquid is liquid at the saturation condition and ready to begin vaporizing when additional heat is added at the same pressure.
• Expanded explanation: —
• Related term(s): Subcooled Liquid
• Commonly confused with: Subcooled Liquid
• Applicable module(s): 3, 4
• EPA 608 / course relevance: Core

Saturated Vapor

• Category: Refrigeration Cycle and Thermodynamics
• Concise definition: A saturated vapor is vapor at the saturation condition and ready to begin condensing when heat is removed at the same pressure.
• Expanded explanation: —
• Related term(s): Superheated Vapor
• Commonly confused with: Superheated Vapor
• Applicable module(s): 3, 4
• EPA 608 / course relevance: Core

Saturation Pressure

• Category: Refrigeration Cycle and Thermodynamics
• Concise definition: Saturation pressure is the pressure corresponding to a refrigerant’s liquid-vapor phase-change condition at a specified saturation temperature.
• Expanded explanation: —
• Related term(s): Liquid-Phase Saturation Pressure
• Commonly confused with: —
• Applicable module(s): 3, 4
• EPA 608 / course relevance: Core

Saturation Temperature

• Category: Refrigeration Cycle and Thermodynamics
• Concise definition: Saturation temperature is the temperature at which liquid and vapor can coexist in equilibrium at a specified saturation pressure.
• Expanded explanation: —
• Related term(s): Saturation Pressure
• Commonly confused with: —
• Applicable module(s): 3, 4, 9
• EPA 608 / course relevance: Core, Type III

SCBA

• Category: Safety
• Concise definition: Self-contained breathing apparatus that supplies breathing air from an independent source.
• Expanded explanation: SCBA is emergency or specialized respiratory protection; it is not the same as an air-purifying respirator and requires appropriate training and program controls.
• Related term(s): Self-Contained Breathing Apparatus (SCBA); IDLH
• Commonly confused with: Ordinary dust mask or air-purifying respirator
• Applicable module(s): 6, 9, 10, 11
• EPA 608 / course relevance: Core; Type III

Scheduled Rule

• Category: Regulatory and Environmental
• Concise definition: A scheduled rule is a finalized requirement with a future compliance date.
• Expanded explanation: —
• Related term(s): Proposed Rule
• Commonly confused with: —
• Applicable module(s): 2
• EPA 608 / course relevance: Core

SDS

• Category: Safety
• Concise definition: Safety Data Sheet; a standardized hazard-information document for a chemical product.
• Expanded explanation: An SDS provides information such as hazards, first aid, handling, storage, exposure controls, and emergency measures.
• Related term(s): Safety Data Sheet (SDS); MSDS
• Commonly confused with: MSDS is the older term
• Applicable module(s): 6, 10, 11
• EPA 608 / course relevance: Core

Section 608

• Category: Regulatory and Environmental
• Concise definition: Section 608 of the Clean Air Act, the federal refrigerant-management program for covered refrigeration and air-conditioning appliances and activities.
• Expanded explanation: It is implemented primarily through 40 CFR Part 82, Subpart F and includes technician certification, recovery, venting restrictions, service practices, sales restrictions, reclamation, safe disposal, and recordkeeping.
• Related term(s): Clean Air Act; 40 CFR Part 82, Subpart F
• Commonly confused with: Section 609
• Applicable module(s): 1, 2, 5, 6, 7, 8, 9, 10, 11
• EPA 608 / course relevance: Core; all Types

Section 608 Technician Certification

• Category: Certification, Examination, and Study
• Concise definition: Section 608 Technician Certification is the federal certification earned by passing an EPA-approved examination for the applicable appliance category.
• Expanded explanation: —
• Related term(s): Section 609 Certification
• Commonly confused with: Section 609
• Applicable module(s): 1
• EPA 608 / course relevance: Core
• Alias / shorthand: Section 608 Certification

Section 609

• Category: Regulatory and Environmental
• Concise definition: The Clean Air Act program that specifically addresses servicing of motor vehicle air conditioners (MVACs).
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: Section 608 Technician Certification
• Applicable module(s): 7
• EPA 608 / course relevance: Type I

Section 609 Certification

• Category: Certification, Examination, and Study
• Concise definition: Section 609 certification applies to technicians who repair or service MVAC systems for consideration and requires training and testing through an EPA-approved program.
• Expanded explanation: —
• Related term(s): Section 608 Technician Certification
• Commonly confused with: —
• Applicable module(s): 1
• EPA 608 / course relevance: Core

Securement

• Category: Disposal, Cylinders, and Shipping
• Concise definition: The method used to prevent cylinders or other packages from shifting, overturning, or being ejected during transportation.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 6
• EPA 608 / course relevance: Core

Self-Contained Breathing Apparatus (SCBA)

• Category: Safety
• Concise definition: An atmosphere-supplying respirator in which the breathing-gas supply is designed to be carried by the user.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 6
• EPA 608 / course relevance: Core

Self-Contained Recovery Equipment

• Category: Recovery and Evacuation
• Concise definition: Recovery and/or recycling equipment capable of removing refrigerant from an appliance without assistance from components contained in the appliance.
• Expanded explanation: It has an independent recovery means and is distinct from system-dependent recovery equipment.
• Related term(s): System-Dependent Recovery Equipment; Recovery Machine
• Commonly confused with: System-Dependent Recovery Equipment
• Applicable module(s): 5, 7
• EPA 608 / course relevance: Core, Type I

Self-Sealing Valve

• Category: General HVAC/R and Service
• Concise definition: A self-sealing valve automatically closes and seals a small MVAC refrigerant container when refrigerant is not being dispensed.
• Expanded explanation: —
• Related term(s): —
• Commonly confused with: —
• Applicable module(s): 2
• EPA 608 / course relevance: Core