9.15 - Answers and Explanations

Module: Type III Low-Pressure Appliances
Covers: All 80 concept-check questions in Sections 9.1–9.10 and all 75 questions in Practice Sets 9.12, 9.13, and 9.14
Total questions answered: 155
Regulatory and safety verification date: August 13, 2026
Primary authorities: Current 40 CFR §§ 82.152, 82.156, and 82.161; current EPA Section 608 Type III test topics; OSHA 29 CFR 1910.146 and 1910.147; current-code review established in Section 9.10
Purpose: Provide the correct answer, explain why it is correct, explain why every distractor is incorrect, identify the tested concept and likely error category, direct the learner to the relevant Module 9 remediation section, and provide a current authoritative source when the answer depends on a current rule.

How to Use This File

Complete the relevant Section 9 concept checks or one complete 25-question Type III practice set before reading the answers.
Score the attempt using the complete answer key below.
Review every incorrect answer and every correct answer that was guessed or selected with low confidence.
For numerical questions, memorize the component or procedure together with the number. Do not memorize 10 psig, 15 psig, 130°F, 5 psig, 0 psig, or 25 mm Hg absolute as isolated values.
Keep recovery and charging sequences separate: recovery = liquid first, then vapor; charging a deeply evacuated low-pressure chiller = vapor first, then liquid when approved.
For low-pressure evacuation questions, read the unit carefully: the current normal Table 1 value is 25 mm Hg absolute, not 25 in. Hg vacuum.
For service-practice exceptions, first decide whether the work is normal/major, qualifying non-major, or affected by a leak that prevents the prescribed level.
For machinery-room safety, distinguish a refrigerant detector from an oxygen monitor and distinguish a hazardous room from the OSHA definition of a confined space.
Enter unresolved items in the project error log and retest them later with a different question.

Mastery rule: A correct guess remains unresolved until the learner can explain why the correct answer is right and why every distractor is wrong.

Complete Module 9 Answer Key

Section 9.1: 9.1-1: A | 9.1-2: C | 9.1-3: B | 9.1-4: C | 9.1-5: A | 9.1-6: B | 9.1-7: C | 9.1-8: A
Section 9.2: 9.2-1: B | 9.2-2: A | 9.2-3: C | 9.2-4: B | 9.2-5: C | 9.2-6: A | 9.2-7: B | 9.2-8: A
Section 9.3: 9.3-1: A | 9.3-2: B | 9.3-3: B | 9.3-4: A | 9.3-5: A | 9.3-6: B | 9.3-7: A | 9.3-8: B
Section 9.4: 9.4-1: A | 9.4-2: C | 9.4-3: C | 9.4-4: B | 9.4-5: B | 9.4-6: A | 9.4-7: A | 9.4-8: B
Section 9.5: 9.5-1: A | 9.5-2: A | 9.5-3: C | 9.5-4: A | 9.5-5: C | 9.5-6: B | 9.5-7: B | 9.5-8: A
Section 9.6: 9.6-1: B | 9.6-2: C | 9.6-3: B | 9.6-4: A | 9.6-5: C | 9.6-6: C | 9.6-7: A | 9.6-8: C
Section 9.7: 9.7-1: A | 9.7-2: C | 9.7-3: B | 9.7-4: B | 9.7-5: A | 9.7-6: A | 9.7-7: B | 9.7-8: C
Section 9.8: 9.8-1: B | 9.8-2: C | 9.8-3: A | 9.8-4: B | 9.8-5: B | 9.8-6: C | 9.8-7: B | 9.8-8: C
Section 9.9: 9.9-1: D | 9.9-2: B | 9.9-3: C | 9.9-4: A | 9.9-5: B | 9.9-6: A | 9.9-7: B | 9.9-8: C
Section 9.10: 9.10-1: B | 9.10-2: B | 9.10-3: A | 9.10-4: A | 9.10-5: C | 9.10-6: C | 9.10-7: C | 9.10-8: B
Section 9.12 - Practice Questions Set 1: 1: A | 2: B | 3: C | 4: D | 5: A | 6: B | 7: C | 8: D | 9: A | 10: B | 11: C | 12: D | 13: A | 14: B | 15: C | 16: D | 17: A | 18: B | 19: C | 20: D | 21: A | 22: B | 23: C | 24: D | 25: A
Section 9.13 - Practice Questions Set 2: 1: B | 2: C | 3: D | 4: A | 5: B | 6: C | 7: D | 8: A | 9: B | 10: C | 11: D | 12: A | 13: B | 14: C | 15: D | 16: A | 17: B | 18: C | 19: D | 20: A | 21: B | 22: C | 23: D | 24: A | 25: B
Section 9.14 - Practice Questions Set 3: 1: C | 2: D | 3: A | 4: B | 5: C | 6: D | 7: A | 8: B | 9: C | 10: D | 11: A | 12: B | 13: C | 14: D | 15: A | 16: B | 17: C | 18: D | 19: A | 20: B | 21: C | 22: D | 23: A | 24: B | 25: C

Answer-File Organization

Parts A–J: Concept-check answers for Sections 9.1–9.10.
Part K: Practice Questions Set 1 from Section 9.12.
Part L: Practice Questions Set 2 from Section 9.13.
Part M: Practice Questions Set 3 from Section 9.14.
Section 9.11 is the Module 9 Quick Reference and contains no separate concept-check questions.
Current-rule answers include an authoritative source.
Traditional exam-preparation values such as the 10 psig recovery-unit cutout, 15 psig recovery-vessel rupture-disc value, and the 350-ton R-11 / approximately 100-lb vapor example are kept in their proper context and are not mislabeled as universal federal requirements.

Part A - 9.1 - Low-Pressure Appliance Fundamentals Answers

Question 9.1-1

Correct answer: A. Below 45 psia at 104°F

Current Section 608 defines a low-pressure appliance by refrigerant liquid-phase saturation pressure below 45 psia at 104°F. This is a refrigerant-pressure classification, not merely a statement that the machine happens to operate below 0 psig.

B is incorrect: Below 45 psig at 32°F does not satisfy the governing Low-pressure appliance classification principle for this scenario. The correct condition is: Below 45 psia at 104°F.
C is incorrect: Between 45 and 170 psia at 104°F does not satisfy the governing Low-pressure appliance classification principle for this scenario. The correct condition is: Below 45 psia at 104°F.
D is incorrect: Above 355 psia at 104°F does not satisfy the governing Low-pressure appliance classification principle for this scenario. The correct condition is: Below 45 psia at 104°F.

Topic: Low-pressure appliance classification
Suggested error code: CLS
Review: 9.1 - Low-Pressure Appliance Fundamentals

Current source: 40 CFR § 82.152 - Definitions

Question 9.1-2

Correct answer: C. Type III

Covered service, repair, maintenance, or disposal work on a low-pressure appliance falls under Type III certification. Type I covers qualifying small appliances, Type II covers applicable medium/high/very-high-pressure appliances, and Section 609 is for MVAC work.

A is incorrect: Type I applies to qualifying small appliances, not the low-pressure Type III condition described here.
B is incorrect: Type II applies to applicable medium-, high-, and very-high-pressure appliances, not a low-pressure appliance.
D is incorrect: Section 609 only is associated with motor-vehicle air-conditioning service, not ordinary Type III low-pressure appliance service.

Topic: Type III certification scope
Suggested error code: CLS
Review: 9.1 - Low-Pressure Appliance Fundamentals

Current source: 40 CFR § 82.161 - Technician Certification

Question 9.1-3

Correct answer: B. Air and moisture can be drawn into the refrigerant circuit

When local refrigerant-side pressure is below atmospheric pressure, the pressure difference drives outside air and moisture inward through a leak. A low-pressure chiller can therefore gain contaminants rather than simply lose refrigerant.

A is incorrect: Refrigerant must always leak outward is too absolute for the condition in this question. The correct answer depends on the specific Type III pressure, equipment, or service condition.
C is incorrect: Chilled water must immediately enter the refrigerant circuit does not satisfy the governing Subatmospheric leak direction principle for this scenario. The correct condition is: Air and moisture can be drawn into the refrigerant circuit.
D is incorrect: No fluid or gas can move through a leak below atmospheric pressure does not satisfy the governing Subatmospheric leak direction principle for this scenario. The correct condition is: Air and moisture can be drawn into the refrigerant circuit.

Topic: Subatmospheric leak direction
Suggested error code: PRS
Review: 9.1 - Low-Pressure Appliance Fundamentals

Question 9.1-4

Correct answer: C. It is an EPA refrigerant-pressure classification based on refrigerant properties.

“Low-pressure appliance” is an EPA refrigerant-pressure category based on refrigerant saturation pressure. It does not mean the appliance has no high side or that every location is always below atmospheric pressure.

A is incorrect: It means the appliance has no high side does not satisfy the governing Meaning of low-pressure appliance principle for this scenario. The correct condition is: It is an EPA refrigerant-pressure classification based on refrigerant properties.
B is incorrect: It means every point in the appliance is always below atmospheric pressure is too absolute for the condition in this question. The correct answer depends on the specific Type III pressure, equipment, or service condition.
D is incorrect: It is another name for the low side of any Type II system applies to applicable medium-, high-, and very-high-pressure appliances, not a low-pressure appliance.

Topic: Meaning of low-pressure appliance
Suggested error code: CLS
Review: 9.1 - Low-Pressure Appliance Fundamentals

Current source: 40 CFR § 82.152 - Definitions

Question 9.1-5

Correct answer: A. Air becomes a noncondensable load that can increase condensing pressure and purge demand.

Air entering a low-pressure chiller becomes a noncondensable load. Noncondensables can add to condenser pressure, reduce heat-transfer effectiveness, and increase purge-system operation.

B is incorrect: Air automatically improves condenser heat transfer is too absolute for the condition in this question. The correct answer depends on the specific Type III pressure, equipment, or service condition.
C is incorrect: Air converts the appliance from Type III to Type II applies to applicable medium-, high-, and very-high-pressure appliances, not a low-pressure appliance.
D is incorrect: Air permanently lowers atmospheric pressure around the chiller does not satisfy the governing Effect of air infiltration principle for this scenario. The correct condition is: Air becomes a noncondensable load that can increase condensing pressure and purge demand.

Topic: Effect of air infiltration
Suggested error code: PUR
Review: 9.1 - Low-Pressure Appliance Fundamentals

Question 9.1-6

Correct answer: B. Refrigerant can leak outward when local internal pressure rises above atmospheric pressure.

Leak direction follows local pressure. When the refrigerant-side pressure at a leak rises above atmospheric pressure, refrigerant can leak outward; low-pressure classification does not prevent this.

A is incorrect: Refrigerant can never leak out of a low-pressure appliance is too absolute for the condition in this question. The correct answer depends on the specific Type III pressure, equipment, or service condition.
C is incorrect: Refrigerant leaks outward only when the evaporator is below atmospheric pressure does not satisfy the governing Positive-pressure leak direction principle for this scenario. The correct condition is: Refrigerant can leak outward when local internal pressure rises above atmospheric pressure.
D is incorrect: Shutdown always guarantees that the entire appliance is at positive pressure is too absolute for the condition in this question. The correct answer depends on the specific Type III pressure, equipment, or service condition.

Topic: Positive-pressure leak direction
Suggested error code: PRS
Review: 9.1 - Low-Pressure Appliance Fundamentals

Question 9.1-7

Correct answer: C. R-123

R-123 is specifically included among the refrigerant examples used with low-pressure appliances in the current federal definition. R-22, R-410A, and R-23 are not low-pressure examples in this classification.

A is incorrect: R-410A does not satisfy the governing Low-pressure refrigerant example principle for this scenario. The correct condition is: R-123.
B is incorrect: R-22 does not satisfy the governing Low-pressure refrigerant example principle for this scenario. The correct condition is: R-123.
D is incorrect: R-23 does not satisfy the governing Low-pressure refrigerant example principle for this scenario. The correct condition is: R-123.

Topic: Low-pressure refrigerant example
Suggested error code: CLS
Review: 9.1 - Low-Pressure Appliance Fundamentals

Question 9.1-8

Correct answer: A. Air may be entering the appliance through a leak.

A purge unit that operates much more frequently than normal can indicate continued air infiltration through a refrigerant-side leak. Purging removes accumulated noncondensables but does not repair the leak.

B is incorrect: The chiller must be a Type I appliance applies to qualifying small appliances, not the low-pressure Type III condition described here.
C is incorrect: The refrigerant has automatically been reclaimed is too absolute for the condition in this question. The correct answer depends on the specific Type III pressure, equipment, or service condition.
D is incorrect: The compressor must be receiving liquid refrigerant does not satisfy the governing Frequent purging as an air-leak clue principle for this scenario. The correct condition is: Air may be entering the appliance through a leak.

Topic: Frequent purging as an air-leak clue
Suggested error code: PUR
Review: 9.1 - Low-Pressure Appliance Fundamentals

Part B - 9.2 - Low-Pressure Chiller Components Answers

Question 9.2-1

Correct answer: B. Evaporator

The evaporator absorbs heat from the chilled-water circuit while refrigerant boils on the refrigerant side of the heat exchanger.

A is incorrect: Condenser rejects heat; it does not absorb the chilled-water load.
C is incorrect: Purge unit removes noncondensables; it is not the heat-absorbing evaporator.
D is incorrect: Rupture disc is an emergency pressure-relief device, not a heat exchanger.

Topic: Evaporator function
Suggested error code: CMP
Review: 9.2 - Low-Pressure Chiller Components

Question 9.2-2

Correct answer: A. Raise the pressure and energy of refrigerant vapor

The centrifugal compressor receives refrigerant vapor and raises its pressure and energy so that the refrigerant can reject heat and condense in the condenser.

B is incorrect: Store condenser water does not satisfy the governing Centrifugal-compressor function principle for this scenario. The correct condition is: Raise the pressure and energy of refrigerant vapor.
C is incorrect: Remove moisture from chilled water does not satisfy the governing Centrifugal-compressor function principle for this scenario. The correct condition is: Raise the pressure and energy of refrigerant vapor.
D is incorrect: Act as the machinery-room refrigerant detector does not satisfy the governing Centrifugal-compressor function principle for this scenario. The correct condition is: Raise the pressure and energy of refrigerant vapor.

Topic: Centrifugal-compressor function
Suggested error code: CMP
Review: 9.2 - Low-Pressure Chiller Components

Question 9.2-3

Correct answer: C. Chilled water passes through the evaporator, while condenser water passes through the condenser.

Chilled water passes through the evaporator water circuit, while condenser water passes through the condenser water circuit. The two water circuits and the refrigerant circuit are normally kept physically separate by the heat-exchanger tubes.

A is incorrect: Chilled water flows through the condenser, and condenser water flows through the evaporator does not satisfy the governing Evaporator and condenser water circuits principle for this scenario. The correct condition is: Chilled water passes through the evaporator, while condenser water passes through the condenser.
B is incorrect: Both water circuits normally mix inside the evaporator shell does not satisfy the governing Evaporator and condenser water circuits principle for this scenario. The correct condition is: Chilled water passes through the evaporator, while condenser water passes through the condenser.
D is incorrect: Condenser water is the refrigerant used by the compressor does not satisfy the governing Evaporator and condenser water circuits principle for this scenario. The correct condition is: Chilled water passes through the evaporator, while condenser water passes through the condenser.

Topic: Evaporator and condenser water circuits
Suggested error code: CMP
Review: 9.2 - Low-Pressure Chiller Components

Question 9.2-4

Correct answer: B. Remove accumulated noncondensable gases while minimizing refrigerant loss

The purge unit removes accumulated noncondensable gases while minimizing refrigerant loss. It is not a normal pressure-control device or a water pump.

A is incorrect: Increase compressor motor speed is not a purge-unit function. The purge unit handles noncondensables in the refrigerant side.
C is incorrect: Replace the condenser-water pump is not a purge-unit function. The purge unit handles noncondensables in the refrigerant side.
D is incorrect: Control normal refrigerant pressure by opening to the atmosphere would create unnecessary refrigerant release and is not the purpose of a purge unit.

Topic: Purge-unit function
Suggested error code: PUR
Review: 9.3 - Air Moisture and Purge Units

Question 9.2-5

Correct answer: C. It provides emergency overpressure protection.

A rupture disc provides emergency overpressure protection. It is a safety device, not a normal charging connection, water drain, or operating pressure regulator.

A is incorrect: It is a normal refrigerant charging valve does not satisfy the governing Rupture-disc protection principle for this scenario. The correct condition is: It provides emergency overpressure protection.
B is incorrect: It is a water-box drain valve is a water-side service connection, not the manufacturer-designated refrigerant charging connection.
D is incorrect: It is the normal device used to regulate evaporator pressure does not satisfy the governing Rupture-disc protection principle for this scenario. The correct condition is: It provides emergency overpressure protection.

Topic: Rupture-disc protection
Suggested error code: SAF
Review: 9.10 - Type III Safety and Machinery Rooms

Question 9.2-6

Correct answer: A. Evaporator charging valve

For Type III exam preparation, centrifugal chillers are charged through the manufacturer-designated evaporator charging valve.

B is incorrect: Rupture-disc outlet is an emergency overpressure-protection connection, not a normal charging point.
C is incorrect: Condenser-water drain is a water-side service connection, not the manufacturer-designated refrigerant charging connection.
D is incorrect: Refrigerant-monitor sampling point does not satisfy the governing Evaporator charging valve principle for this scenario. The correct condition is: Evaporator charging valve.

Topic: Evaporator charging valve
Suggested error code: CHG
Review: 9.8 - Recharging Low-Pressure Systems

Exam-topic source: EPA - Section 608 Test Topics

Question 9.2-7

Correct answer: B. Conventional oil-lubricated chillers use oil to protect bearings and related components, but some modern centrifugal chillers are oil-free.

Conventional oil-lubricated centrifugal chillers use oil to protect bearings and related components, but some modern centrifugal chillers use oil-free bearing technologies. The actual machine design controls the service procedure.

A is incorrect: Every centrifugal chiller must use an identical external oil pump does not satisfy the governing Centrifugal-chiller oil system principle for this scenario. The correct condition is: Conventional oil-lubricated chillers use oil to protect bearings and related components, but some modern centrifugal chillers are oil-free.
C is incorrect: Oil normally flows through the chilled-water tubes does not satisfy the governing Centrifugal-chiller oil system principle for this scenario. The correct condition is: Conventional oil-lubricated chillers use oil to protect bearings and related components, but some modern centrifugal chillers are oil-free.
D is incorrect: The oil system serves as the purge unit does not satisfy the governing Centrifugal-chiller oil system principle for this scenario. The correct condition is: Conventional oil-lubricated chillers use oil to protect bearings and related components, but some modern centrifugal chillers are oil-free.

Topic: Centrifugal-chiller oil system
Suggested error code: OIL
Review: 9.7 - Refrigerant in Oil

Question 9.2-8

Correct answer: A. Refrigerant concentration in room air

A machinery-room refrigerant monitor detects target refrigerant concentration in room air. It does not measure chilled-water flow, compressor oil level, or refrigerant pressure inside the chiller.

B is incorrect: Chilled-water flow through the evaporator does not satisfy the governing Machinery-room refrigerant monitoring principle for this scenario. The correct condition is: Refrigerant concentration in room air.
C is incorrect: Oil level inside every centrifugal compressor does not satisfy the governing Machinery-room refrigerant monitoring principle for this scenario. The correct condition is: Refrigerant concentration in room air.
D is incorrect: Condenser refrigerant saturation pressure does not satisfy the governing Machinery-room refrigerant monitoring principle for this scenario. The correct condition is: Refrigerant concentration in room air.

Topic: Machinery-room refrigerant monitoring
Suggested error code: SAF
Review: 9.10 - Type III Safety and Machinery Rooms

Part C - 9.3 - Air Moisture and Purge Units Answers

Question 9.3-1

Correct answer: A. Remove noncondensable gases from the refrigerant system

The purge unit removes noncondensable gases from the refrigerant system while minimizing refrigerant loss. It is not a substitute for refrigerant recovery during major service.

B is incorrect: Increase the chilled-water flow rate is not a purge-unit function. The purge unit handles noncondensables in the refrigerant side.
C is incorrect: Raise the compressor discharge pressure does not satisfy the governing Purge-unit function principle for this scenario. The correct condition is: Remove noncondensable gases from the refrigerant system.
D is incorrect: Replace the refrigerant recovery machine during major service does not satisfy the governing Purge-unit function principle for this scenario. The correct condition is: Remove noncondensable gases from the refrigerant system.

Topic: Purge-unit function
Suggested error code: PUR
Review: 9.3 - Air Moisture and Purge Units

Question 9.3-2

Correct answer: B. Atmospheric pressure is greater than the local internal refrigerant pressure.

Atmospheric air enters because atmospheric pressure is greater than the local internal refrigerant pressure. The pressure difference, not a chemical attraction, drives the inward leakage.

A is incorrect: Refrigerant chemically attracts oxygen does not satisfy the governing Air infiltration under vacuum principle for this scenario. The correct condition is: Atmospheric pressure is greater than the local internal refrigerant pressure.
C is incorrect: The purge unit pumps outdoor air into the chiller does not satisfy the governing Air infiltration under vacuum principle for this scenario. The correct condition is: Atmospheric pressure is greater than the local internal refrigerant pressure.
D is incorrect: Condenser water always flows into the refrigerant circuit is too absolute for the condition in this question. The correct answer depends on the specific Type III pressure, equipment, or service condition.

Topic: Air infiltration under vacuum
Suggested error code: PRS
Review: 9.3 - Air Moisture and Purge Units

Question 9.3-3

Correct answer: B. Top / upper region of the condenser

In the traditional Type III model, noncondensables collect in the upper condenser region, so the purge unit draws the refrigerant/noncondensable mixture from that general location.

A is incorrect: Bottom of the evaporator liquid pool does not satisfy the governing Purge-unit pickup location principle for this scenario. The correct condition is: Top / upper region of the condenser.
C is incorrect: Chilled-water pump suction does not satisfy the governing Purge-unit pickup location principle for this scenario. The correct condition is: Top / upper region of the condenser.
D is incorrect: Oil drain connection only does not satisfy the governing Purge-unit pickup location principle for this scenario. The correct condition is: Top / upper region of the condenser.

Topic: Purge-unit pickup location
Suggested error code: PUR
Review: 9.3 - Air Moisture and Purge Units

Question 9.3-4

Correct answer: A. Air may be entering the chiller through a leak.

A significant increase in purge operation suggests that air may be entering through a leak. The purge removes accumulated noncondensables, but the leak still must be located and corrected.

B is incorrect: The evaporator must be overcharged with chilled water does not satisfy the governing Frequent purging as a leak indicator principle for this scenario. The correct condition is: Air may be entering the chiller through a leak.
C is incorrect: The chiller has automatically changed to Type II applies to applicable medium-, high-, and very-high-pressure appliances, not a low-pressure appliance.
D is incorrect: Frequent purging proves that no leak exists does not satisfy the governing Frequent purging as a leak indicator principle for this scenario. The correct condition is: Air may be entering the chiller through a leak.

Topic: Frequent purging as a leak indicator
Suggested error code: PUR
Review: 9.3 - Air Moisture and Purge Units

Question 9.3-5

Correct answer: A. They contribute additional gas pressure in the condenser region.

Noncondensables remain gaseous in the condenser and contribute additional partial pressure. This can raise total condenser/head pressure and interfere with normal heat rejection.

B is incorrect: They automatically lower condenser-water temperature is too absolute for the condition in this question. The correct answer depends on the specific Type III pressure, equipment, or service condition.
C is incorrect: They convert liquid refrigerant into compressor oil does not satisfy the governing Noncondensables and condenser pressure principle for this scenario. The correct condition is: They contribute additional gas pressure in the condenser region.
D is incorrect: They reduce atmospheric pressure around the chiller does not satisfy the governing Noncondensables and condenser pressure principle for this scenario. The correct condition is: They contribute additional gas pressure in the condenser region.

Topic: Noncondensables and condenser pressure
Suggested error code: PUR
Review: 9.3 - Air Moisture and Purge Units

Question 9.3-6

Correct answer: B. Condense/retain as much refrigerant as practical and return it to the chiller while removing noncondensables.

A high-efficiency purge process separates noncondensables while condensing or retaining as much refrigerant as practical for return to the system. The refrigerant portion is not intentionally vented with the air.

A is incorrect: Intentionally vent all refrigerant with the air conflicts with refrigerant-conservation requirements; remaining refrigerant must be recovered rather than intentionally vented.
C is incorrect: Convert the refrigerant permanently into a noncondensable gas does not satisfy the governing Refrigerant conservation in purge operation principle for this scenario. The correct condition is: Condense/retain as much refrigerant as practical and return it to the chiller while removing noncondensables.
D is incorrect: Send the refrigerant into the condenser-water circuit does not satisfy the governing Refrigerant conservation in purge operation principle for this scenario. The correct condition is: Condense/retain as much refrigerant as practical and return it to the chiller while removing noncondensables.

Topic: Refrigerant conservation in purge operation
Suggested error code: PUR
Review: 9.3 - Air Moisture and Purge Units

Question 9.3-7

Correct answer: A. A possible water-side heat-exchanger tube leak

Unusually high moisture removal by the purge system can indicate water entering the refrigerant side, including a possible heat-exchanger tube leak. The clue requires investigation rather than automatic diagnosis.

B is incorrect: An open compressor discharge valve does not satisfy the governing Moisture as a tube-leak clue principle for this scenario. The correct condition is: A possible water-side heat-exchanger tube leak.
C is incorrect: A refrigerant cylinder that is too cold does not satisfy the governing Moisture as a tube-leak clue principle for this scenario. The correct condition is: A possible water-side heat-exchanger tube leak.
D is incorrect: A Type I small-appliance restriction applies to qualifying small appliances, not the low-pressure Type III condition described here.

Topic: Moisture as a tube-leak clue
Suggested error code: PUR
Review: 9.3 - Air Moisture and Purge Units

Question 9.3-8

Correct answer: B. The purge unit removes noncondensables, but the leak allowing air or moisture to enter still must be located and corrected.

The purge unit removes noncondensables after they enter the system, but it does not seal or repair the leak. The source of air or moisture infiltration must still be found and corrected.

A is incorrect: The purge unit repairs the leak by removing air confuses symptom control with repair; purging removes noncondensables but the leak still must be corrected.
C is incorrect: A purge unit makes leak repair unnecessary on all low-pressure chillers confuses symptom control with repair; purging removes noncondensables but the leak still must be corrected.
D is incorrect: Purge operation can only occur after all refrigerant has been recovered does not satisfy the governing Purge unit versus leak repair principle for this scenario. The correct condition is: The purge unit removes noncondensables, but the leak allowing air or moisture to enter still must be located and corrected.

Topic: Purge unit versus leak repair
Suggested error code: PUR
Review: 9.3 - Air Moisture and Purge Units

Part D - 9.4 - Low-Pressure Leak Detection and Pressurization Answers

Question 9.4-1

Correct answer: A. Controlled hot water or an approved heating/pressurization method

Controlled hot water or another approved heat-based pressurization method is the preferred first method for raising a charged low-pressure chiller to a leak-test condition.

B is incorrect: Oxygen directly from a cylinder is not an acceptable refrigerant-system pressure-test gas and can create serious safety hazards; regulated dry nitrogen is used only where permitted.
C is incorrect: Compressed shop air is not an acceptable refrigerant-system pressure-test gas and can create serious safety hazards; regulated dry nitrogen is used only where permitted.
D is incorrect: Immediately raise the system to the rupture-disc pressure does not satisfy the governing Heat-based low-pressure leak-test pressurization principle for this scenario. The correct condition is: Controlled hot water or an approved heating/pressurization method.

Topic: Heat-based low-pressure leak-test pressurization
Suggested error code: LKD
Review: 9.4 - Low-Pressure Leak Detection and Pressurization

Question 9.4-2

Correct answer: C. Regulated nitrogen where permitted

If controlled heat is not feasible, regulated nitrogen is the next Type III leak-test method where permitted. Oxygen and compressed air are unsafe substitutes.

A is incorrect: Oxygen is not an acceptable refrigerant-system pressure-test gas and can create serious safety hazards; regulated dry nitrogen is used only where permitted.
B is incorrect: Acetylene does not satisfy the governing Regulated nitrogen after heat-based pressurization principle for this scenario. The correct condition is: Regulated nitrogen where permitted.
D is incorrect: Compressed air is not an acceptable refrigerant-system pressure-test gas and can create serious safety hazards; regulated dry nitrogen is used only where permitted.

Topic: Regulated nitrogen after heat-based pressurization
Suggested error code: LKD
Review: 9.4 - Low-Pressure Leak Detection and Pressurization

Question 9.4-3

Correct answer: C. 10 psig

For Type III exam preparation, the charged low-pressure chiller leak-test maximum is 10 psig. It is a ceiling rather than a target, and any lower manufacturer limit controls in actual field work.

A is incorrect: 0 psig belongs to the qualifying non-major opening context, not the Type III leak-test maximum.
B is incorrect: 5 psig is associated with the oil-change provision, not the Type III leak-test maximum.
D is incorrect: 15 psig is the traditional low-pressure recovery-vessel rupture-disc value, not the charged-chiller leak-test maximum.

Topic: Type III leak-test pressure maximum
Suggested error code: NUM
Review: 9.4 - Low-Pressure Leak Detection and Pressurization

Question 9.4-4

Correct answer: B. The chiller leak-test exam-preparation maximum is 10 psig, while the 15-psig rupture-disc value specifically refers to a low-pressure recovery vessel.

The 10 psig value is the Type III leak-test maximum used for a charged low-pressure chiller. The separate 15 psig value belongs to the traditional low-pressure recovery-vessel rupture-disc context and is not a universal chiller relief rating.

A is incorrect: Every low-pressure chiller rupture disc is universally 15 psig, and the leak-test maximum is also 15 psig is the traditional low-pressure recovery-vessel rupture-disc value, not the charged-chiller leak-test maximum.
C is incorrect: A 150 psig chiller leak-test value is far above the Type III exam-preparation maximum, and assigning 10 psig to the recovery-vessel rupture disc also reverses the traditional recovery-equipment values.
D is incorrect: The 10- and 15-psig values both refer only to chilled-water pressure assigns the 10 psig and 15 psig values to the wrong component or procedure. The correct pairing is given in the correct answer.

Topic: 10 psig leak-test value versus 15 psig recovery-vessel value
Suggested error code: NUM
Review: 9.4 - Low-Pressure Leak Detection and Pressurization

Question 9.4-5

Correct answer: B. Remove the water from the water box.

For the traditional water-box leak check, remove the water before inserting the refrigerant detector probe through the drain opening. This lets refrigerant leaking into the water side be detected.

A is incorrect: Fill the water box completely with water does not satisfy the governing Water-box leak checking principle for this scenario. The correct condition is: Remove the water from the water box.
C is incorrect: Pressurize the water box to 150 psig with oxygen does not satisfy the governing Water-box leak checking principle for this scenario. The correct condition is: Remove the water from the water box.
D is incorrect: Open the rupture disc does not satisfy the governing Water-box leak checking principle for this scenario. The correct condition is: Remove the water from the water box.

Topic: Water-box leak checking
Suggested error code: LKD
Review: 9.4 - Low-Pressure Leak Detection and Pressurization

Safety source: OSHA 29 CFR 1910.147 - The Control of Hazardous Energy

Question 9.4-6

Correct answer: A. Hydrostatic tube test kit

A hydrostatic tube test kit is the traditional Type III method for checking individual chiller tubes for leakage.

B is incorrect: Vacuum cleaner does not satisfy the governing Tube-leak testing principle for this scenario. The correct condition is: Hydrostatic tube test kit.
C is incorrect: Recovery-cylinder scale does not satisfy the governing Tube-leak testing principle for this scenario. The correct condition is: Hydrostatic tube test kit.
D is incorrect: Crankcase heater does not satisfy the governing Tube-leak testing principle for this scenario. The correct condition is: Hydrostatic tube test kit.

Topic: Tube-leak testing
Suggested error code: LKD
Review: 9.4 - Low-Pressure Leak Detection and Pressurization

Question 9.4-7

Correct answer: A. Shaft seal

An open-drive compressor has a shaft penetration through the housing, so the shaft seal is a classic refrigerant leak location.

B is incorrect: Hermetic motor winding inside a welded shell does not satisfy the governing Open-drive shaft-seal leak location principle for this scenario. The correct condition is: Shaft seal.
C is incorrect: Cooling-tower fan blade does not satisfy the governing Open-drive shaft-seal leak location principle for this scenario. The correct condition is: Shaft seal.
D is incorrect: Chilled-water expansion tank only does not satisfy the governing Open-drive shaft-seal leak location principle for this scenario. The correct condition is: Shaft seal.

Topic: Open-drive shaft-seal leak location
Suggested error code: LKD
Review: 9.4 - Low-Pressure Leak Detection and Pressurization

Question 9.4-8

Correct answer: B. The appliance must be pressurized to no higher than 0 psig before opening, and nitrogen use is restricted by the rule’s refrigerant boiling-point conditions.

The 10 psig leak-test ceiling does not authorize opening the appliance at 10 psig. Under the limited current non-major provision, the appliance is pressurized to no higher than 0 psig before opening when all conditions are satisfied, and nitrogen use is restricted by refrigerant boiling point.

A is incorrect: The 10-psig leak-test maximum means the appliance may be opened at 10 psig belongs to a different Type III context, such as leak testing or the traditional recovery-unit cutout, not this evacuation/opening condition.
C is incorrect: The appliance must always be opened while under deep vacuum is too absolute for the condition in this question. The correct answer depends on the specific Type III pressure, equipment, or service condition.
D is incorrect: Nitrogen must always be used regardless of refrigerant ignores the current method restrictions. Nitrogen is not universally permitted in the qualifying low-pressure non-major procedure.

Topic: Qualifying non-major low-pressure opening
Suggested error code: REG
Review: 9.9 - Type III Evacuation Requirements

Current source: 40 CFR § 82.156 - Proper Evacuation of Refrigerant From Appliances; 40 CFR § 82.152 - Definitions

Part E - 9.5 - Type III Recovery Sequence Answers

Question 9.5-1

Correct answer: A. Recover bulk liquid first.

Accessible bulk liquid is recovered first because liquid contains much more refrigerant mass per unit volume than vapor, so liquid-first recovery removes the charge more efficiently.

B is incorrect: Recover vapor only from the beginning is slower when accessible bulk liquid can be removed first; liquid-first recovery removes refrigerant mass more efficiently.
C is incorrect: Vent the vapor and recover only the oil conflicts with refrigerant-conservation requirements; remaining refrigerant must be recovered rather than intentionally vented.
D is incorrect: Run the chiller compressor until the system reaches atmospheric pressure does not satisfy the governing Liquid-first recovery principle for this scenario. The correct condition is: Recover bulk liquid first.

Topic: Liquid-first recovery
Suggested error code: REC
Review: 9.5 - Type III Recovery Sequence

Question 9.5-2

Correct answer: A. A substantial refrigerant vapor mass can remain in the large internal volume of the chiller.

A large low-pressure chiller can still contain substantial refrigerant vapor after accessible liquid is removed. Recovery must therefore continue through the vapor phase.

B is incorrect: Vapor recovery is required only to cool the condenser water does not satisfy the governing Vapor recovery after liquid removal principle for this scenario. The correct condition is: A substantial refrigerant vapor mass can remain in the large internal volume of the chiller.
C is incorrect: Removing liquid automatically creates noncondensables that must be vented is too absolute for the condition in this question. The correct answer depends on the specific Type III pressure, equipment, or service condition.
D is incorrect: The recovery vessel cannot accept liquid refrigerant does not satisfy the governing Vapor recovery after liquid removal principle for this scenario. The correct condition is: A substantial refrigerant vapor mass can remain in the large internal volume of the chiller.

Topic: Vapor recovery after liquid removal
Suggested error code: REC
Review: 9.5 - Type III Recovery Sequence

Question 9.5-3

Correct answer: C. Approximately 100 lb of vapor

The traditional exam example uses an average 350-ton R-11 chiller at 0 psig and approximately 100 lb of refrigerant vapor remaining after liquid removal. The number illustrates the principle; it is not universal for every chiller.

A is incorrect: Approximately 1 lb of vapor does not match the representative Type III example, which uses approximately 100 lb of remaining vapor.
B is incorrect: Approximately 10 lb of vapor does not match the representative Type III example, which uses approximately 100 lb of remaining vapor.
D is incorrect: No vapor remains at 0 psig does not match the representative Type III example, which uses approximately 100 lb of remaining vapor.

Topic: Classic remaining-vapor example
Suggested error code: REC
Review: 9.5 - Type III Recovery Sequence

Question 9.5-4

Correct answer: A. Remove heat from compressed recovered refrigerant so it can condense and be transferred to the recovery vessel

The recovery-machine condenser rejects heat from compressed recovered refrigerant so that it can condense and move into the recovery vessel.

B is incorrect: Circulate chilled water through the building describes a different chiller or water-side function. The recovery-machine condenser rejects heat from compressed recovered refrigerant so it can condense.
C is incorrect: Raise the chiller evaporator pressure for charging describes a different chiller or water-side function. The recovery-machine condenser rejects heat from compressed recovered refrigerant so it can condense.
D is incorrect: Remove oil from the chiller compressor bearings describes a different chiller or water-side function. The recovery-machine condenser rejects heat from compressed recovered refrigerant so it can condense.

Topic: Recovery-machine condenser
Suggested error code: REC
Review: 9.5 - Type III Recovery Sequence

Question 9.5-5

Correct answer: C. 10 psig

The traditional Type III exam-preparation high-pressure cutout value for the low-pressure recovery unit is 10 psig. This value belongs to the recovery unit, not the final chiller evacuation requirement.

A is incorrect: 0 psig belongs to another service context and is not the traditional recovery-unit high-pressure cutout.
B is incorrect: 5 psig belongs to another service context and is not the traditional recovery-unit high-pressure cutout.
D is incorrect: 15 psig is the traditional low-pressure recovery-vessel rupture-disc value; the recovery-unit high-pressure cutout value is 10 psig.

Topic: Recovery-unit high-pressure cutout
Suggested error code: NUM
Review: 9.5 - Type III Recovery Sequence

Question 9.5-6

Correct answer: B. The recovery-unit high-pressure cutout is 10 psig and the low-pressure recovery-vessel rupture disc is 15 psig.

The traditional low-pressure recovery-unit high-pressure cutout is 10 psig, while the low-pressure recovery-vessel rupture disc is 15 psig. Neither is the normal Type III evacuation endpoint or a universal chiller relief rating.

A is incorrect: The recovery-unit high-pressure cutout is 15 psig and the recovery-vessel rupture disc is 10 psig is the traditional recovery-unit high-pressure cutout, not the recovery-vessel rupture-disc value.
C is incorrect: Both values describe the current regulatory evacuation endpoint assigns the 10 psig and 15 psig values to the wrong component or procedure. The correct pairing is given in the correct answer.
D is incorrect: Both values are universal rupture-disc settings for the chiller itself assigns the 10 psig and 15 psig values to the wrong component or procedure. The correct pairing is given in the correct answer.

Topic: Recovery-unit cutout versus recovery-vessel rupture disc
Suggested error code: NUM
Review: 9.5 - Type III Recovery Sequence

Question 9.5-7

Correct answer: B. Chiller water pumps on; recovery compressor on; recovery condenser cooling water on

In the traditional normal recovery condition, chiller water pumps, the recovery compressor, and recovery-condenser cooling water are operating as required. Chiller water circulation limits freeze risk; recovery-condenser water removes recovery heat.

A is incorrect: Chiller water pumps off; recovery compressor off; recovery condenser water off does not satisfy the governing Normal Type III recovery operating condition principle for this scenario. The correct condition is: Chiller water pumps on; recovery compressor on; recovery condenser cooling water on.
C is incorrect: Chiller water pumps off; recovery compressor on; recovery condenser water off does not satisfy the governing Normal Type III recovery operating condition principle for this scenario. The correct condition is: Chiller water pumps on; recovery compressor on; recovery condenser cooling water on.
D is incorrect: Chiller water pumps on; recovery compressor off; recovery condenser water off does not satisfy the governing Normal Type III recovery operating condition principle for this scenario. The correct condition is: Chiller water pumps on; recovery compressor on; recovery condenser cooling water on.

Topic: Normal Type III recovery operating condition
Suggested error code: REC
Review: 9.5 - Type III Recovery Sequence

Question 9.5-8

Correct answer: A. Refrigerant may still remain as liquid or may be coming out of the oil, so additional recovery may be required.

After the required recovery endpoint is reached, pressure can rise because refrigerant remains as residual liquid or is leaving the oil. Additional recovery may therefore be required.

B is incorrect: The chiller is necessarily completely empty is too absolute. Pressure rise can have more than one cause and must be interpreted in the context of recovery or post-service vacuum diagnosis.
C is incorrect: The recovery-vessel rupture disc must have opened does not satisfy the governing Pressure rebound after recovery principle for this scenario. The correct condition is: Refrigerant may still remain as liquid or may be coming out of the oil, so additional recovery may be required.
D is incorrect: The technician should vent the remaining vapor to stop the pressure rise conflicts with refrigerant-conservation requirements; remaining refrigerant must be recovered rather than intentionally vented.

Topic: Pressure rebound after recovery
Suggested error code: VAC
Review: 9.9 - Type III Evacuation Requirements

Part F - 9.6 - Freeze Prevention During Recovery Answers

Question 9.6-1

Correct answer: B. To prevent water in the chiller from freezing as refrigerant pressure and saturation temperature fall

Water must be circulated or removed because lowering refrigerant pressure lowers saturation temperature. Remaining refrigerant can boil at a low enough temperature to freeze water in the heat-exchanger tubes.

A is incorrect: To increase the refrigerant’s ozone-depletion potential does not satisfy the governing Freeze prevention during evacuation principle for this scenario. The correct condition is: To prevent water in the chiller from freezing as refrigerant pressure and saturation temperature fall.
C is incorrect: To raise the recovery cylinder above its maximum fill level does not satisfy the governing Freeze prevention during evacuation principle for this scenario. The correct condition is: To prevent water in the chiller from freezing as refrigerant pressure and saturation temperature fall.
D is incorrect: To convert refrigerant vapor into noncondensable gas does not satisfy the governing Freeze prevention during evacuation principle for this scenario. The correct condition is: To prevent water in the chiller from freezing as refrigerant pressure and saturation temperature fall.

Topic: Freeze prevention during evacuation
Suggested error code: FRZ
Review: 9.6 - Freeze Prevention During Recovery

Question 9.6-2

Correct answer: C. It decreases.

For a refrigerant at saturation, lowering absolute pressure lowers saturation temperature. This relationship is the thermodynamic basis of the Type III freeze-up concern during deep recovery.

A is incorrect: It increases does not satisfy the governing Pressure-saturation-temperature relationship principle for this scenario. The correct condition is: It decreases.
B is incorrect: It remains fixed for all refrigerants ignores the refrigerant saturation pressure-temperature relationship.
D is incorrect: It becomes unrelated to pressure does not satisfy the governing Pressure-saturation-temperature relationship principle for this scenario. The correct condition is: It decreases.

Topic: Pressure-saturation-temperature relationship
Suggested error code: PT
Review: 9.6 - Freeze Prevention During Recovery

Question 9.6-3

Correct answer: B. Drain the water sides of the evaporator and condenser.

When a tube leak is suspected, the water sides of the evaporator and condenser are drained before refrigerant recovery under the Type III procedure so water is not driven into the refrigerant circuit as pressure falls.

A is incorrect: Increase water pressure in both heat exchangers does not satisfy the governing Suspected tube leak and water-side draining principle for this scenario. The correct condition is: Drain the water sides of the evaporator and condenser.
C is incorrect: Add liquid refrigerant until the chiller reaches positive pressure does not satisfy the governing Suspected tube leak and water-side draining principle for this scenario. The correct condition is: Drain the water sides of the evaporator and condenser.
D is incorrect: Stop all leak investigation and operate the chiller at full load does not satisfy the governing Suspected tube leak and water-side draining principle for this scenario. The correct condition is: Drain the water sides of the evaporator and condenser.

Topic: Suspected tube leak and water-side draining
Suggested error code: FRZ
Review: 9.6 - Freeze Prevention During Recovery

Safety source: OSHA 29 CFR 1910.147 - The Control of Hazardous Energy

Question 9.6-4

Correct answer: A. The liquid can flash rapidly to vapor and absorb heat from nearby metal and water.

Liquid introduced directly into a deep vacuum can flash rapidly to vapor. Flash evaporation absorbs latent heat, producing strong local cooling that can freeze water in nearby tubes.

B is incorrect: The liquid immediately becomes warmer than the water does not satisfy the governing Flash cooling from liquid added into deep vacuum principle for this scenario. The correct condition is: The liquid can flash rapidly to vapor and absorb heat from nearby metal and water.
C is incorrect: Liquid refrigerant eliminates all evaporation does not satisfy the governing Flash cooling from liquid added into deep vacuum principle for this scenario. The correct condition is: The liquid can flash rapidly to vapor and absorb heat from nearby metal and water.
D is incorrect: Liquid refrigerant raises the water freezing point above room temperature does not satisfy the governing Flash cooling from liquid added into deep vacuum principle for this scenario. The correct condition is: The liquid can flash rapidly to vapor and absorb heat from nearby metal and water.

Topic: Flash cooling from liquid added into deep vacuum
Suggested error code: CHG
Review: 9.8 - Recharging Low-Pressure Systems

Question 9.6-5

Correct answer: C. Refrigerant vapor

EPA Type III test topics call for vapor to be introduced before liquid when recharging a deeply evacuated low-pressure chiller. Vapor charging raises pressure and saturation temperature while reducing freeze risk.

A is incorrect: Solid refrigerant does not satisfy the governing Vapor-first Type III charging principle for this scenario. The correct condition is: Refrigerant vapor.
B is incorrect: Liquid refrigerant does not satisfy the governing Vapor-first Type III charging principle for this scenario. The correct condition is: Refrigerant vapor.
D is incorrect: Refrigerant mixed with nitrogen does not satisfy the governing Vapor-first Type III charging principle for this scenario. The correct condition is: Refrigerant vapor.

Topic: Vapor-first Type III charging
Suggested error code: CHG
Review: 9.8 - Recharging Low-Pressure Systems

Exam-topic source: EPA - Section 608 Test Topics

Question 9.6-6

Correct answer: C. When the approved refrigerant and chiller manufacturer procedure indicates that conditions are safe

There is no universal pressure for switching every low-pressure chiller from vapor to liquid charging. The manufacturer-approved refrigerant and chiller procedure determines when conditions are safe.

A is incorrect: At one universal pressure that applies to every Type III appliance invents a universal or premature transition. The manufacturer-approved conditions control the switch to liquid charging.
B is incorrect: As soon as the recovery machine is disconnected, regardless of system condition does not satisfy the governing Vapor-to-liquid charging transition principle for this scenario. The correct condition is: When the approved refrigerant and chiller manufacturer procedure indicates that conditions are safe.
D is incorrect: Before any vapor has entered the chiller does not satisfy the governing Vapor-to-liquid charging transition principle for this scenario. The correct condition is: When the approved refrigerant and chiller manufacturer procedure indicates that conditions are safe.

Topic: Vapor-to-liquid charging transition
Suggested error code: CHG
Review: 9.8 - Recharging Low-Pressure Systems

Question 9.6-7

Correct answer: A. Moving water continually brings heat to locally cooled tube surfaces and reduces stagnant cold spots.

Moving water continually brings heat to locally cooled tube surfaces and prevents the same small volume of water from remaining at a severe cold spot, reducing freeze-up risk.

B is incorrect: Moving water raises refrigerant pressure above the recovery-machine cutout does not satisfy the governing Water circulation for freeze prevention principle for this scenario. The correct condition is: Moving water continually brings heat to locally cooled tube surfaces and reduces stagnant cold spots.
C is incorrect: Moving water converts refrigerant vapor into oxygen does not satisfy the governing Water circulation for freeze prevention principle for this scenario. The correct condition is: Moving water continually brings heat to locally cooled tube surfaces and reduces stagnant cold spots.
D is incorrect: Moving water eliminates the need to recover vapor does not satisfy the governing Water circulation for freeze prevention principle for this scenario. The correct condition is: Moving water continually brings heat to locally cooled tube surfaces and reduces stagnant cold spots.

Topic: Water circulation for freeze prevention
Suggested error code: FRZ
Review: 9.6 - Freeze Prevention During Recovery

Question 9.6-8

Correct answer: C. Water should be circulated or removed to prevent freezing, with suspected tube leakage requiring the appropriate draining procedure.

A is incorrect: Water must always remain stagnant in both heat exchangers is too absolute for the condition in this question. The correct answer depends on the specific Type III pressure, equipment, or service condition.
B is incorrect: Water must always be circulated even when a tube leak is suspected is too absolute for the condition in this question. The correct answer depends on the specific Type III pressure, equipment, or service condition.
D is incorrect: Water-side condition has no effect on refrigerant recovery.

— does not satisfy the governing Freeze prevention during evacuation principle for this scenario. The correct condition is: Water should be circulated or removed to prevent freezing, with suspected tube leakage requiring the appropriate draining procedure.

Topic: Freeze prevention during evacuation
Suggested error code: FRZ
Review: 9.6 - Freeze Prevention During Recovery

Part G - 9.7 - Refrigerant in Oil Answers

Question 9.7-1

Correct answer: A. Refrigerant can remain dissolved in the compressor oil.

Refrigerant can remain dissolved in compressor oil even after bulk liquid and much of the free vapor have been removed. As pressure or temperature changes, that refrigerant can leave the oil and become recoverable vapor.

B is incorrect: Refrigerant permanently converts to water does not satisfy the governing Refrigerant dissolved in oil principle for this scenario. The correct condition is: Refrigerant can remain dissolved in the compressor oil.
C is incorrect: The condenser-water circuit creates new refrigerant does not satisfy the governing Refrigerant dissolved in oil principle for this scenario. The correct condition is: Refrigerant can remain dissolved in the compressor oil.
D is incorrect: Recovery equipment cannot remove any vapor from a chiller does not satisfy the governing Refrigerant dissolved in oil principle for this scenario. The correct condition is: Refrigerant can remain dissolved in the compressor oil.

Topic: Refrigerant dissolved in oil
Suggested error code: OIL
Review: 9.7 - Refrigerant in Oil

Question 9.7-2

Correct answer: C. 130°F

Current EPA Type III test topics identify 130°F as the oil-heating examination value before oil removal to minimize refrigerant release.

A is incorrect: 85°F is not the current Type III oil-heating examination value; the module uses 130°F.
B is incorrect: 100°F is not the current Type III oil-heating examination value; the module uses 130°F.
D is incorrect: 212°F is not the current Type III oil-heating examination value; the module uses 130°F.

Topic: 130°F oil-heating exam value
Suggested error code: OIL
Review: 9.7 - Refrigerant in Oil

Exam-topic source: EPA - Section 608 Test Topics

Question 9.7-3

Correct answer: B. To help refrigerant leave the oil so it can be captured by the recovery process.

Heating the oil helps drive dissolved refrigerant out of the lubricant so that the released vapor can be captured by the recovery process before the oil is removed.

A is incorrect: To increase the amount of refrigerant retained permanently in the oil is opposite the objective; heating is used to drive refrigerant out of the oil so it can be recovered.
C is incorrect: To raise the refrigerant’s ozone-depletion potential does not satisfy the governing Purpose of oil heating principle for this scenario. The correct condition is: To help refrigerant leave the oil so it can be captured by the recovery process.
D is incorrect: To convert compressor oil into refrigerant does not satisfy the governing Purpose of oil heating principle for this scenario. The correct condition is: To help refrigerant leave the oil so it can be captured by the recovery process.

Topic: Purpose of oil heating
Suggested error code: OIL
Review: 9.7 - Refrigerant in Oil

Question 9.7-4

Correct answer: B. The appliance or isolated portion may be opened for an oil change only after it is evacuated or pressurized to no higher than 5 psig, or the permitted system-receiver procedure may be used.

Current §82.156 permits opening for an oil change after the appliance or isolated portion is evacuated or pressurized to no higher than 5 psig, or through the permitted system-receiver procedure.

A is incorrect: The appliance must always be opened at exactly 10 psig belongs to a different Type III context, such as leak testing or the traditional recovery-unit cutout, not this evacuation/opening condition.
C is incorrect: The appliance must always be opened under 15 psig belongs to a different Type III procedure; the current oil-change opening condition is no higher than 5 psig (or the permitted receiver procedure).
D is incorrect: No pressure requirement applies because refrigerant contained in oil is exempt does not satisfy the governing Current oil-change pressure condition principle for this scenario. The correct condition is: The appliance or isolated portion may be opened for an oil change only after it is evacuated or pressurized to no higher than 5 psig, or the permitted system-receiver procedure may be used.

Topic: Current oil-change pressure condition
Suggested error code: REG
Review: 9.7 - Refrigerant in Oil

Current source: 40 CFR § 82.156 - Proper Evacuation of Refrigerant From Appliances; 40 CFR § 82.152 - Definitions

Question 9.7-5

Correct answer: A. Rapid boiling of dissolved refrigerant out of the oil after a pressure reduction.

Oil foaming occurs when dissolved refrigerant rapidly boils out of the lubricant, commonly after a rapid pressure reduction.

B is incorrect: Condenser water changing into compressor oil does not describe oil foaming. Foaming is caused by dissolved refrigerant rapidly boiling out of the oil.
C is incorrect: A refrigerant monitor measuring room air does not describe oil foaming. Foaming is caused by dissolved refrigerant rapidly boiling out of the oil.
D is incorrect: The recovery vessel becoming completely empty does not describe oil foaming. Foaming is caused by dissolved refrigerant rapidly boiling out of the oil.

Topic: Oil foaming
Suggested error code: OIL
Review: 9.7 - Refrigerant in Oil

Question 9.7-6

Correct answer: A. Refrigerant may still be leaving the oil or vaporizing from another internal source.

A pressure rise after isolation can occur because refrigerant is still leaving the oil or vaporizing from another internal source. It does not automatically prove an external leak or prove recovery complete.

B is incorrect: The oil has become a noncondensable gas does not satisfy the governing Pressure rebound from refrigerant in oil principle for this scenario. The correct condition is: Refrigerant may still be leaving the oil or vaporizing from another internal source.
C is incorrect: The chiller is necessarily completely refrigerant-free is too absolute. Pressure rise can have more than one cause and must be interpreted in the context of recovery or post-service vacuum diagnosis.
D is incorrect: The pressure rise proves the recovery-machine condenser is full of water is too absolute. Pressure rise can have more than one cause and must be interpreted in the context of recovery or post-service vacuum diagnosis.

Topic: Pressure rebound from refrigerant in oil
Suggested error code: VAC
Review: 9.9 - Type III Evacuation Requirements

Question 9.7-7

Correct answer: B. The 130°F value is important Type III examination knowledge, while actual oil heating and removal must also follow the chiller manufacturer’s approved limits and procedure.

The 130°F value is important Type III examination knowledge, but actual oil heating and oil removal must remain within manufacturer-approved temperature and service limits for the specific chiller.

A is incorrect: The 130°F value allows every oil system to be heated without regard to equipment limits does not satisfy the governing Exam value versus manufacturer limits principle for this scenario. The correct condition is: The 130°F value is important Type III examination knowledge, while actual oil heating and removal must also follow the chiller manufacturer’s approved limits and procedure.
C is incorrect: Manufacturer instructions can be ignored during certification-related service does not satisfy the governing Exam value versus manufacturer limits principle for this scenario. The correct condition is: The 130°F value is important Type III examination knowledge, while actual oil heating and removal must also follow the chiller manufacturer’s approved limits and procedure.
D is incorrect: The 130°F value applies only to condenser-water temperature does not satisfy the governing Exam value versus manufacturer limits principle for this scenario. The correct condition is: The 130°F value is important Type III examination knowledge, while actual oil heating and removal must also follow the chiller manufacturer’s approved limits and procedure.

Topic: Exam value versus manufacturer limits
Suggested error code: OIL
Review: 9.7 - Refrigerant in Oil

Question 9.7-8

Correct answer: C. The appliance must still satisfy the applicable recovery/evacuation requirement, and pressure rebound may show that additional refrigerant remains.

Removing heated oil does not prove the appliance is refrigerant-free. The applicable recovery/evacuation requirement must still be met, and pressure rebound may indicate additional refrigerant remains.

A is incorrect: Oil removal automatically proves that all refrigerant has been recovered incorrectly treats oil removal as the end of refrigerant recovery. The applicable recovery/evacuation requirement still controls.
B is incorrect: The technician may vent any remaining vapor after the oil is removed conflicts with refrigerant-conservation requirements; remaining refrigerant must be recovered rather than intentionally vented.
D is incorrect: The final evacuation requirement no longer applies to Type III appliances incorrectly treats oil removal as the end of refrigerant recovery. The applicable recovery/evacuation requirement still controls.

Topic: Oil removal versus recovery completion
Suggested error code: OIL
Review: 9.7 - Refrigerant in Oil

Part H - 9.8 - Recharging Low-Pressure Systems Answers

Question 9.8-1

Correct answer: B. Through the evaporator charging valve

For Type III examination preparation, a centrifugal chiller is charged through the manufacturer-designated evaporator charging valve.

A is incorrect: Through the condenser-water drain is a water-side service connection, not the manufacturer-designated refrigerant charging connection.
C is incorrect: Through the rupture-disc connection is an emergency overpressure-protection connection, not a normal charging point.
D is incorrect: Through the purge discharge outlet is associated with noncondensable removal, not the normal centrifugal-chiller charging connection.

Topic: Evaporator charging valve
Suggested error code: CHG
Review: 9.8 - Recharging Low-Pressure Systems

Exam-topic source: EPA - Section 608 Test Topics

Question 9.8-2

Correct answer: C. Vapor helps raise system pressure and saturation temperature while reducing the risk of freezing water in the tubes.

Initial vapor charging raises internal pressure and refrigerant saturation temperature while avoiding the severe flash cooling caused by adding bulk liquid into a deep vacuum.

A is incorrect: Vapor lowers system pressure more quickly does not satisfy the governing Vapor-first Type III charging principle for this scenario. The correct condition is: Vapor helps raise system pressure and saturation temperature while reducing the risk of freezing water in the tubes.
B is incorrect: Vapor eliminates the need to evacuate the system is false; vapor-first charging does not replace the required prior evacuation/dehydration procedure.
D is incorrect: Vapor converts noncondensables into liquid refrigerant does not satisfy the governing Vapor-first Type III charging principle for this scenario. The correct condition is: Vapor helps raise system pressure and saturation temperature while reducing the risk of freezing water in the tubes.

Topic: Vapor-first Type III charging
Suggested error code: CHG
Review: 9.8 - Recharging Low-Pressure Systems

Exam-topic source: EPA - Section 608 Test Topics

Question 9.8-3

Correct answer: A. The liquid can flash rapidly, absorb heat, and freeze water in the evaporator tubes.

Bulk liquid entering a deep vacuum can flash rapidly, absorb latent heat, and cool the evaporator/tube area enough to freeze water in the tubes.

B is incorrect: The liquid immediately raises the water temperature above boiling does not describe the real hazard: liquid can flash rapidly in deep vacuum, absorb latent heat, and create severe local cooling.
C is incorrect: The liquid prevents refrigerant pressure from changing conflicts with refrigerant-conservation requirements; remaining refrigerant must be recovered rather than intentionally vented.
D is incorrect: The liquid permanently disables the purge unit does not describe the real hazard: liquid can flash rapidly in deep vacuum, absorb latent heat, and create severe local cooling.

Topic: Flash cooling and tube freezing
Suggested error code: CHG
Review: 9.8 - Recharging Low-Pressure Systems

Question 9.8-4

Correct answer: B. It rises as pressure rises.

As vapor is added, system pressure rises. For refrigerant near saturation, higher pressure corresponds to a higher saturation temperature, which reduces freeze risk.

A is incorrect: It decreases as pressure rises reverses the saturation pressure-temperature relationship used here. Raising pressure raises saturation temperature.
C is incorrect: It remains fixed regardless of pressure ignores the refrigerant saturation pressure-temperature relationship.
D is incorrect: It becomes equal to outdoor air temperature ignores the refrigerant saturation pressure-temperature relationship.

Topic: Pressure rise during initial vapor charging
Suggested error code: PT
Review: 9.8 - Recharging Low-Pressure Systems

Question 9.8-5

Correct answer: B. Use the manufacturer-designated evaporator charging connection associated with the low refrigerant-side region.

The “lowest access point” concept refers to the manufacturer-designated low refrigerant-side evaporator charging connection. A physically low fitting is not automatically an approved charging port.

A is incorrect: Use any fitting that is physically closest to the floor does not satisfy the governing Meaning of lowest access point principle for this scenario. The correct condition is: Use the manufacturer-designated evaporator charging connection associated with the low refrigerant-side region.
C is incorrect: Use the lowest condenser-water drain is a water-side service connection, not the manufacturer-designated refrigerant charging connection.
D is incorrect: Use the lowest purge-unit fitting does not satisfy the governing Meaning of lowest access point principle for this scenario. The correct condition is: Use the manufacturer-designated evaporator charging connection associated with the low refrigerant-side region.

Topic: Meaning of lowest access point
Suggested error code: CHG
Review: 9.8 - Recharging Low-Pressure Systems

Question 9.8-6

Correct answer: C. When the manufacturer-approved procedure indicates that pressure, saturation temperature, water conditions, and other required conditions permit liquid charging

The transition to controlled liquid charging occurs only when the manufacturer-approved procedure indicates that pressure, saturation temperature, water conditions, and other required conditions are safe.

A is incorrect: At one universal pressure used for all Type III chillers invents a universal or premature transition. The manufacturer-approved conditions control the switch to liquid charging.
B is incorrect: Immediately after the first vapor enters the appliance invents a universal or premature transition. The manufacturer-approved conditions control the switch to liquid charging.
D is incorrect: Only after the chiller is operating at full load does not satisfy the governing Vapor-to-liquid charging transition principle for this scenario. The correct condition is: When the manufacturer-approved procedure indicates that pressure, saturation temperature, water conditions, and other required conditions permit liquid charging.

Topic: Vapor-to-liquid charging transition
Suggested error code: CHG
Review: 9.8 - Recharging Low-Pressure Systems

Question 9.8-7

Correct answer: B. Follow the approved procedure so the refrigerant is properly metered or vaporized as needed before it enters the deeply evacuated chiller during the initial stage.

A blend may need to leave its supply cylinder as liquid to preserve composition, but an approved method can meter or vaporize it so that vapor enters the deeply evacuated chiller during the initial freeze-prevention stage.

A is incorrect: Send unrestricted liquid directly into the chiller because the cylinder must supply liquid does not satisfy the governing Blend handling during Type III charging principle for this scenario. The correct condition is: Follow the approved procedure so the refrigerant is properly metered or vaporized as needed before it enters the deeply evacuated chiller during the initial stage.
C is incorrect: Mix nitrogen with the liquid refrigerant does not satisfy the governing Blend handling during Type III charging principle for this scenario. The correct condition is: Follow the approved procedure so the refrigerant is properly metered or vaporized as needed before it enters the deeply evacuated chiller during the initial stage.
D is incorrect: Skip the vapor-first requirement whenever a blend is used is too absolute for the condition in this question. The correct answer depends on the specific Type III pressure, equipment, or service condition.

Topic: Blend handling during Type III charging
Suggested error code: CHG
Review: 9.8 - Recharging Low-Pressure Systems

Question 9.8-8

Correct answer: C. Evaporator charging valve → vapor first → pressure and saturation temperature rise → controlled liquid charging when approved

The correct sequence is to use the evaporator charging valve, introduce vapor first, allow pressure and saturation temperature to rise, and then transition to controlled liquid charging when the approved procedure permits.

A is incorrect: Liquid first → lower pressure → freeze tubes → vapor last defeats the Type III freeze-prevention sequence. A deeply evacuated chiller is initially charged with vapor, not uncontrolled bulk liquid.
B is incorrect: Condenser charging → open relief device → liquid only does not satisfy the governing Type III recharging sequence principle for this scenario. The correct condition is: Evaporator charging valve → vapor first → pressure and saturation temperature rise → controlled liquid charging when approved.
D is incorrect: Purge connection → compressed air → liquid refrigerant is associated with noncondensable removal, not the normal centrifugal-chiller charging connection.

Topic: Type III recharging sequence
Suggested error code: CHG
Review: 9.8 - Recharging Low-Pressure Systems

Part I - 9.9 - Type III Evacuation Requirements Answers

Question 9.9-1

Correct answer: D. 25 mm Hg absolute

The current normal Section 608 Table 1 evacuation requirement for a low-pressure appliance is 25 mm Hg absolute.

A is incorrect: 4 inches Hg vacuum is associated with other pressure-category evacuation conditions, not the normal Type III low-pressure Table 1 endpoint.
B is incorrect: 10 inches Hg vacuum is associated with other pressure-category evacuation conditions, not the normal Type III low-pressure Table 1 endpoint.
C is incorrect: 15 inches Hg vacuum is associated with other pressure-category evacuation conditions, not the normal Type III low-pressure Table 1 endpoint.

Topic: Current Type III evacuation requirement
Suggested error code: EVA
Review: 9.9 - Type III Evacuation Requirements

Current source: 40 CFR § 82.156 - Proper Evacuation of Refrigerant From Appliances; EPA - Required Level of Evacuation of Appliances

Question 9.9-2

Correct answer: B. It is an absolute pressure of 25 millimeters of mercury above perfect vacuum.

“25 mm Hg absolute” is an absolute pressure measured upward from perfect vacuum. It is not 25 inches of mercury vacuum, 25 psig, or 500 microns.

A is incorrect: It means 25 inches of mercury below atmospheric pressure confuses inches of mercury vacuum with the current low-pressure requirement of 25 mm Hg absolute.
C is incorrect: It means the appliance must be at 25 psig is positive gauge pressure and is not the required low-pressure evacuation condition.
D is incorrect: It is another way to state 500 microns exactly is a deeper technical dehydration benchmark sometimes used in service practice; it is not identical to 25 mm Hg absolute.

Topic: Meaning of 25 mm Hg absolute
Suggested error code: UNIT
Review: 9.9 - Type III Evacuation Requirements

Current source: 40 CFR § 82.156 - Proper Evacuation of Refrigerant From Appliances; EPA - Required Level of Evacuation of Appliances

Question 9.9-3

Correct answer: C. Both require 25 mm Hg absolute.

The normal low-pressure Table 1 endpoint is 25 mm Hg absolute for recovery/recycling equipment both before and on/after November 15, 1993. The date applies to the recovery equipment, not the chiller.

A is incorrect: Post-1993 equipment requires 15 in. Hg vacuum, while older equipment requires 4 in. Hg vacuum gives a different low-pressure endpoint, but the current low-pressure row is 25 mm Hg absolute in both date columns.
B is incorrect: Post-1993 equipment requires 10 in. Hg vacuum, while older equipment requires 0 psig gives a different low-pressure endpoint, but the current low-pressure row is 25 mm Hg absolute in both date columns.
D is incorrect: The requirement depends only on whether the chiller was manufactured before 1993 gives a different low-pressure endpoint, but the current low-pressure row is 25 mm Hg absolute in both date columns.

Topic: Recovery-equipment date and Type III endpoint
Suggested error code: EVA
Review: 9.9 - Type III Evacuation Requirements

Current source: 40 CFR § 82.156 - Proper Evacuation of Refrigerant From Appliances; EPA - Required Level of Evacuation of Appliances

Question 9.9-4

Correct answer: A. A pressure rise can indicate that liquid refrigerant or refrigerant dissolved in oil still remains.

After reaching the required recovery vacuum, waiting a few minutes allows residual liquid refrigerant or refrigerant leaving oil to reveal itself through a pressure rise.

B is incorrect: The wait converts refrigerant vapor into nitrogen does not satisfy the governing Pressure-rebound check after recovery principle for this scenario. The correct condition is: A pressure rise can indicate that liquid refrigerant or refrigerant dissolved in oil still remains.
C is incorrect: The wait determines the recovery cylinder’s DOT test date does not satisfy the governing Pressure-rebound check after recovery principle for this scenario. The correct condition is: A pressure rise can indicate that liquid refrigerant or refrigerant dissolved in oil still remains.
D is incorrect: Pressure must always rise to atmospheric pressure before service is too absolute for the condition in this question. The correct answer depends on the specific Type III pressure, equipment, or service condition.

Topic: Pressure-rebound check after recovery
Suggested error code: VAC
Review: 9.9 - Type III Evacuation Requirements

Exam-topic source: EPA - Section 608 Test Topics

Question 9.9-5

Correct answer: B. Removing the evaporator from the appliance

Current §82.152 includes removal of the evaporator among the operations defined as major maintenance, service, or repair.

A is incorrect: Replacing an external cabinet label does not meet the current major-repair condition identified in the question. The correct answer matches the §82.152 definition.
C is incorrect: Tightening an external mounting bolt does not meet the current major-repair condition identified in the question. The correct answer matches the §82.152 definition.
D is incorrect: Replacing external pipe insulation does not meet the current major-repair condition identified in the question. The correct answer matches the §82.152 definition.

Topic: Major maintenance, service, or repair
Suggested error code: REG
Review: 9.9 - Type III Evacuation Requirements

Current source: 40 CFR § 82.156 - Proper Evacuation of Refrigerant From Appliances; 40 CFR § 82.152 - Definitions

Question 9.9-6

Correct answer: A. No higher than 0 psig

For the limited current non-major provision, the low-pressure appliance is pressurized to no higher than 0 psig before opening when all regulatory conditions are satisfied.

B is incorrect: Exactly 5 psig belongs to the current oil-change provision, not this Type III condition.
C is incorrect: Exactly 10 psig belongs to a different Type III context, such as leak testing or the traditional recovery-unit cutout, not this evacuation/opening condition.
D is incorrect: 25 psig is positive gauge pressure and is not the required low-pressure evacuation condition.

Topic: Qualifying non-major low-pressure opening
Suggested error code: REG
Review: 9.9 - Type III Evacuation Requirements

Current source: 40 CFR § 82.156 - Proper Evacuation of Refrigerant From Appliances; 40 CFR § 82.152 - Definitions

Question 9.9-7

Correct answer: B. Evacuate it to the lowest attainable level without substantial contamination, and the level may not exceed 0 psig.

If a leak prevents 25 mm Hg absolute or deeper evacuation would substantially contaminate recovered refrigerant, the leaking component is taken to the lowest attainable level without substantial contamination, and that level may not exceed 0 psig.

A is incorrect: Leave it at any pressure because a leak exists incorrectly treats the existence of a leak as an exemption from recovery. A good-faith recovery effort and the lowest-attainable-level rule still apply.
C is incorrect: Pressurize it to 10 psig and open it immediately belongs to a different Type III context, such as leak testing or the traditional recovery-unit cutout, not this evacuation/opening condition.
D is incorrect: Vent the remaining refrigerant to atmosphere conflicts with refrigerant-conservation requirements; remaining refrigerant must be recovered rather than intentionally vented.

Topic: Leaking-appliance evacuation exception
Suggested error code: REG
Review: 9.9 - Type III Evacuation Requirements

Current source: 40 CFR § 82.156 - Proper Evacuation of Refrigerant From Appliances; 40 CFR § 82.152 - Definitions

Question 9.9-8

Correct answer: C. The rise can result from remaining refrigerant, refrigerant leaving oil, moisture/outgassing, or leakage, so the cause must be evaluated.

A continuing pressure rise can be caused by remaining refrigerant, refrigerant leaving oil, moisture/outgassing, or leakage. The pressure trend must be diagnosed rather than assigned one automatic cause.

A is incorrect: The rise proves with certainty that only moisture is present is too absolute. Pressure rise can have more than one cause and must be interpreted in the context of recovery or post-service vacuum diagnosis.
B is incorrect: The rise proves with certainty that only an external leak is present is too absolute. Pressure rise can have more than one cause and must be interpreted in the context of recovery or post-service vacuum diagnosis.
D is incorrect: Any pressure rise means the appliance automatically satisfies the Section 608 requirement is too absolute. Pressure rise can have more than one cause and must be interpreted in the context of recovery or post-service vacuum diagnosis.

Topic: Pressure-rise diagnosis after evacuation
Suggested error code: VAC
Review: 9.9 - Type III Evacuation Requirements

Part J - 9.10 - Type III Safety and Machinery Rooms Answers

Question 9.10-1

Correct answer: B. To provide emergency overpressure protection

A rupture disc provides emergency overpressure protection. It is not a normal evaporator pressure regulator, charging device, or purge device.

A is incorrect: To regulate normal evaporator pressure continuously does not satisfy the governing Rupture-disc protection principle for this scenario. The correct condition is: To provide emergency overpressure protection.
C is incorrect: To meter liquid refrigerant into the evaporator does not satisfy the governing Rupture-disc protection principle for this scenario. The correct condition is: To provide emergency overpressure protection.
D is incorrect: To remove noncondensables from the condenser does not satisfy the governing Rupture-disc protection principle for this scenario. The correct condition is: To provide emergency overpressure protection.

Topic: Rupture-disc protection
Suggested error code: SAF
Review: 9.10 - Type III Safety and Machinery Rooms

Question 9.10-2

Correct answer: B. A rupture disc is non-reclosing after it ruptures, while many pressure-relief valves can reclose after pressure decreases.

A rupture disc is non-reclosing after it ruptures, while many spring-loaded pressure-relief valves can reclose after pressure falls. Both are emergency protection devices rather than normal controls.

A is incorrect: A rupture disc normally reseats after opening, while a relief valve never can is too absolute for the condition in this question. The correct answer depends on the specific Type III pressure, equipment, or service condition.
C is incorrect: A rupture disc is a refrigerant detector, while a relief valve is an oxygen detector does not satisfy the governing Rupture disc versus relief valve principle for this scenario. The correct condition is: A rupture disc is non-reclosing after it ruptures, while many pressure-relief valves can reclose after pressure decreases.
D is incorrect: The two devices always have identical construction and service procedures is too absolute for the condition in this question. The correct answer depends on the specific Type III pressure, equipment, or service condition.

Topic: Rupture disc versus relief valve
Suggested error code: SAF
Review: 9.10 - Type III Safety and Machinery Rooms

Question 9.10-3

Correct answer: A. The downstream valve can restrict or block the required relief flow and interfere with the upstream device’s protection.

Two ordinary relief valves should not simply be installed in series because the downstream device can restrict or block the required relief path. Approved engineered relief arrangements are different.

B is incorrect: Two relief valves in series always reduce refrigerant pressure to a vacuum is too absolute for the condition in this question. The correct answer depends on the specific Type III pressure, equipment, or service condition.
C is incorrect: Series installation converts both valves into charging valves does not satisfy the governing Pressure-relief arrangement principle for this scenario. The correct condition is: The downstream valve can restrict or block the required relief flow and interfere with the upstream device’s protection.
D is incorrect: A second relief valve causes refrigerant to become noncondensable does not satisfy the governing Pressure-relief arrangement principle for this scenario. The correct condition is: The downstream valve can restrict or block the required relief flow and interfere with the upstream device’s protection.

Topic: Pressure-relief arrangement
Suggested error code: SAF
Review: 9.10 - Type III Safety and Machinery Rooms

Question 9.10-4

Correct answer: A. Refrigerant concentration in room air

A machinery-room refrigerant monitor measures refrigerant concentration in room air. It is not a water-pressure, oil-level, or shell-thickness instrument.

B is incorrect: Chilled-water pressure inside every tube does not satisfy the governing Machinery-room refrigerant monitoring principle for this scenario. The correct condition is: Refrigerant concentration in room air.
C is incorrect: Compressor oil level does not satisfy the governing Machinery-room refrigerant monitoring principle for this scenario. The correct condition is: Refrigerant concentration in room air.
D is incorrect: Evaporator shell thickness does not satisfy the governing Machinery-room refrigerant monitoring principle for this scenario. The correct condition is: Refrigerant concentration in room air.

Topic: Machinery-room refrigerant monitoring
Suggested error code: SAF
Review: 9.10 - Type III Safety and Machinery Rooms

Question 9.10-5

Correct answer: C. Less than 19.5% oxygen

Under OSHA general-industry confined-space terminology, an atmosphere with less than 19.5% oxygen by volume is oxygen deficient.

A is incorrect: Less than 23.5% oxygen is not the OSHA general-industry oxygen-deficiency threshold; the threshold is less than 19.5% O₂.
B is incorrect: Less than 21.0% oxygen is not the OSHA general-industry oxygen-deficiency threshold; the threshold is less than 19.5% O₂.
D is incorrect: Less than 10.0% oxygen only is not the OSHA general-industry oxygen-deficiency threshold; the threshold is less than 19.5% O₂.

Topic: Oxygen-deficient atmosphere
Suggested error code: SAF
Review: 9.10 - Type III Safety and Machinery Rooms

Safety source: OSHA 29 CFR 1910.146 - Permit-Required Confined Spaces

Question 9.10-6

Correct answer: C. The actual space must be evaluated against the OSHA confined-space criteria; a machinery room is not automatically a confined space.

A refrigeration machinery room is not automatically an OSHA confined space. The actual space must be evaluated against the regulatory criteria for entry/exit and continuous occupancy.

A is incorrect: Every machinery room is automatically a permit-required confined space is too absolute for the condition in this question. The correct answer depends on the specific Type III pressure, equipment, or service condition.
B is incorrect: A machinery room is never allowed to contain a confined space is too absolute for the condition in this question. The correct answer depends on the specific Type III pressure, equipment, or service condition.
D is incorrect: Any room containing a refrigerant detector is automatically a confined space is too absolute for the condition in this question. The correct answer depends on the specific Type III pressure, equipment, or service condition.

Topic: Confined-space evaluation
Suggested error code: SAF
Review: 9.10 - Type III Safety and Machinery Rooms

Safety source: OSHA 29 CFR 1910.146 - Permit-Required Confined Spaces

Question 9.10-7

Correct answer: C. Isolate the water circuit, control applicable hazardous energy, relieve stored pressure, drain/vent as required, verify the safe condition, and then open the cover using the approved lifting procedure.

Stopping the pump does not prove zero water pressure. Before opening the cover, isolate the circuit, control applicable hazardous energy, relieve pressure, drain/vent, verify the condition, and use the approved lifting procedure.

A is incorrect: Assume the water side is depressurized because the pump stopped ignores static head, trapped pressure, expansion pressure, and other stored energy that can remain after a pump stops.
B is incorrect: Loosen several cover bolts so trapped pressure can force its way out is unsafe; stored pressure must be relieved through the approved isolation/drain/vent procedure before cover bolts are loosened.
D is incorrect: Pressurize the water box with refrigerant before removing the cover does not satisfy the governing Water-box stored-energy safety principle for this scenario. The correct condition is: Isolate the water circuit, control applicable hazardous energy, relieve stored pressure, drain/vent as required, verify the safe condition, and then open the cover using the approved lifting procedure.

Topic: Water-box stored-energy safety
Suggested error code: WTR
Review: 9.10 - Type III Safety and Machinery Rooms

Safety source: OSHA 29 CFR 1910.147 - The Control of Hazardous Energy

Question 9.10-8

Correct answer: B. EPA test topics identify certification knowledge, while field design and service must also follow the applicable adopted refrigeration safety code, AHJ requirements, manufacturer instructions, and workplace safety rules.

EPA Type III test topics identify certification knowledge. Actual field design and service must also follow the locally adopted refrigeration safety code, AHJ requirements, equipment listing, manufacturer instructions, and workplace safety procedures.

A is incorrect: Memorizing EPA test-topic phrases eliminates the need to check the adopted safety code does not satisfy the governing Exam topics versus machinery-room code compliance principle for this scenario. The correct condition is: EPA test topics identify certification knowledge, while field design and service must also follow the applicable adopted refrigeration safety code, AHJ requirements, manufacturer instructions, and workplace safety rules.
C is incorrect: ASHRAE standards are irrelevant to Type III machinery rooms does not satisfy the governing Exam topics versus machinery-room code compliance principle for this scenario. The correct condition is: EPA test topics identify certification knowledge, while field design and service must also follow the applicable adopted refrigeration safety code, AHJ requirements, manufacturer instructions, and workplace safety rules.
D is incorrect: The newest published standard automatically becomes law in every jurisdiction on its publication date is too absolute for the condition in this question. The correct answer depends on the specific Type III pressure, equipment, or service condition.

Topic: Exam topics versus machinery-room code compliance
Suggested error code: SAF
Review: 9.10 - Type III Safety and Machinery Rooms

Code source: ASHRAE Read-Only Standards

Part K - Section 9.12 Practice Questions Set 1 Answers

Question 1

Correct answer: A. Liquid-phase saturation pressure below 45 psia at 104°F

Current Section 608 defines a low-pressure appliance by refrigerant liquid-phase saturation pressure below 45 psia at 104°F. This pressure category is the basis for Type III scope.

B is incorrect: Liquid-phase saturation pressure above 355 psia at 104°F does not satisfy the governing Low-pressure appliance classification principle for this scenario. The correct condition is: Liquid-phase saturation pressure below 45 psia at 104°F.
C is incorrect: Any appliance operating below 0 psig at any time does not satisfy the governing Low-pressure appliance classification principle for this scenario. The correct condition is: Liquid-phase saturation pressure below 45 psia at 104°F.
D is incorrect: Any centrifugal chiller containing more than 200 lb of refrigerant does not satisfy the governing Low-pressure appliance classification principle for this scenario. The correct condition is: Liquid-phase saturation pressure below 45 psia at 104°F.

Topic: Low-pressure appliance classification
Suggested error code: CLS
Review: 9.1 - Low-Pressure Appliance Fundamentals

Current source: 40 CFR § 82.152 - Definitions

Question 2

Correct answer: B. Remove noncondensable gases while minimizing refrigerant loss

The purge unit removes noncondensable gases while minimizing refrigerant loss. It is not a chilled-water pressure control, refrigerant metering device, or substitute for the service recovery machine.

A is incorrect: Raise chilled-water pressure does not satisfy the governing Purge-unit function principle for this scenario. The correct condition is: Remove noncondensable gases while minimizing refrigerant loss.
C is incorrect: Meter liquid refrigerant into the evaporator does not satisfy the governing Purge-unit function principle for this scenario. The correct condition is: Remove noncondensable gases while minimizing refrigerant loss.
D is incorrect: Replace the recovery machine during service does not satisfy the governing Purge-unit function principle for this scenario. The correct condition is: Remove noncondensable gases while minimizing refrigerant loss.

Topic: Purge-unit function
Suggested error code: PUR
Review: 9.3 - Air Moisture and Purge Units

Question 3

Correct answer: C. Air and moisture can be drawn into the chiller

When local chiller pressure is below atmospheric pressure, outside air and moisture can be drawn inward through a refrigerant-side leak.

A is incorrect: Only liquid refrigerant can leave the system does not satisfy the governing Subatmospheric leak direction principle for this scenario. The correct condition is: Air and moisture can be drawn into the chiller.
B is incorrect: Condenser water must leak into the refrigerant circuit does not satisfy the governing Subatmospheric leak direction principle for this scenario. The correct condition is: Air and moisture can be drawn into the chiller.
D is incorrect: The purge unit automatically seals the leak is too absolute for the condition in this question. The correct answer depends on the specific Type III pressure, equipment, or service condition.

Topic: Subatmospheric leak direction
Suggested error code: PRS
Review: 9.1 - Low-Pressure Appliance Fundamentals

Question 4

Correct answer: D. They add their partial pressure and interfere with normal condensation

Noncondensables can raise condenser pressure, but condenser-water temperature, flow, and fouling also affect heat rejection. High head pressure is therefore not proof of noncondensables by itself.

A is incorrect: They increase the refrigerant’s latent heat to an unlimited value does not satisfy the governing High condenser pressure differential diagnosis principle for this scenario. The correct condition is: They add their partial pressure and interfere with normal condensation.
B is incorrect: They lower the condenser-water temperature does not satisfy the governing High condenser pressure differential diagnosis principle for this scenario. The correct condition is: They add their partial pressure and interfere with normal condensation.
C is incorrect: They convert the refrigerant to a solid does not satisfy the governing High condenser pressure differential diagnosis principle for this scenario. The correct condition is: They add their partial pressure and interfere with normal condensation.

Topic: High condenser pressure differential diagnosis
Suggested error code: PUR
Review: 9.3 - Air Moisture and Purge Units

Question 5

Correct answer: A. Controlled hot water or an approved heating/pressurization method

Controlled hot water or another approved heat-based method is the preferred first approach for raising pressure in a charged low-pressure chiller for leak testing.

B is incorrect: Oxygen through the charging valve is not an acceptable refrigerant-system pressure-test gas and can create serious safety hazards; regulated dry nitrogen is used only where permitted.
C is incorrect: Compressed air through the purge connection is not an acceptable refrigerant-system pressure-test gas and can create serious safety hazards; regulated dry nitrogen is used only where permitted.
D is incorrect: Unregulated nitrogen until the relief device opens does not satisfy the governing Heat-based low-pressure leak-test pressurization principle for this scenario. The correct condition is: Controlled hot water or an approved heating/pressurization method.

Topic: Heat-based low-pressure leak-test pressurization
Suggested error code: LKD
Review: 9.4 - Low-Pressure Leak Detection and Pressurization

Question 6

Correct answer: B. 10 psig

The Type III exam-preparation maximum for pressurizing a charged low-pressure chiller for leak testing is 10 psig. It is a ceiling, and a lower manufacturer limit controls in field work.

A is incorrect: 0 psig belongs to the qualifying non-major opening context, not the Type III leak-test maximum.
C is incorrect: 5 psig is associated with the oil-change provision, not the Type III leak-test maximum.
D is incorrect: 15 psig is the traditional low-pressure recovery-vessel rupture-disc value, not the charged-chiller leak-test maximum.

Topic: Type III leak-test pressure maximum
Suggested error code: NUM
Review: 9.4 - Low-Pressure Leak Detection and Pressurization

Question 7

Correct answer: C. Drain the water and place the detector probe through the drain opening

The traditional water-box check is performed after draining the water, with a compatible refrigerant detector used at the drain opening.

A is incorrect: Pressurize the water box with oxygen does not satisfy the governing Water-box leak checking principle for this scenario. The correct condition is: Drain the water and place the detector probe through the drain opening.
B is incorrect: Fill the water box with refrigerant does not satisfy the governing Water-box leak checking principle for this scenario. The correct condition is: Drain the water and place the detector probe through the drain opening.
D is incorrect: Operate the chiller compressor with the water box open does not satisfy the governing Water-box leak checking principle for this scenario. The correct condition is: Drain the water and place the detector probe through the drain opening.

Topic: Water-box leak checking
Suggested error code: LKD
Review: 9.4 - Low-Pressure Leak Detection and Pressurization

Safety source: OSHA 29 CFR 1910.147 - The Control of Hazardous Energy

Question 8

Correct answer: D. Bulk liquid refrigerant

Bulk liquid is removed first because it contains much greater refrigerant mass per unit volume, making liquid-first recovery faster and more efficient.

A is incorrect: Noncondensables is not the refrigerant phase that should be removed first when accessible bulk liquid is present.
B is incorrect: Oil is not the refrigerant phase that should be removed first when accessible bulk liquid is present.
C is incorrect: Water from the condenser is not the refrigerant phase that should be removed first when accessible bulk liquid is present.

Topic: Liquid-first recovery
Suggested error code: REC
Review: 9.5 - Type III Recovery Sequence

Question 9

Correct answer: A. 10 psig

The correct choice follows the liquid-first/vapor-second Type III recovery sequence: 10 psig.

B is incorrect: 5 psig does not satisfy the governing Type III recovery sequence principle for this scenario. The correct condition is: 10 psig.
C is incorrect: 15 psig does not satisfy the governing Type III recovery sequence principle for this scenario. The correct condition is: 10 psig.
D is incorrect: 25 psig does not satisfy the governing Type III recovery sequence principle for this scenario. The correct condition is: 10 psig.

Topic: Type III recovery sequence
Suggested error code: REC
Review: 9.5 - Type III Recovery Sequence

Question 10

Correct answer: B. Reject heat from compressed recovered refrigerant so it can condense

The recovery-machine condenser rejects heat from compressed recovered refrigerant so it can condense and move into the recovery vessel.

A is incorrect: Cool the building chilled-water loop describes a different chiller or water-side function. The recovery-machine condenser rejects heat from compressed recovered refrigerant so it can condense.
C is incorrect: Separate water from the chiller oil describes a different chiller or water-side function. The recovery-machine condenser rejects heat from compressed recovered refrigerant so it can condense.
D is incorrect: Raise the chiller evaporator pressure for leak testing describes a different chiller or water-side function. The recovery-machine condenser rejects heat from compressed recovered refrigerant so it can condense.

Topic: Recovery-machine condenser
Suggested error code: REC
Review: 9.5 - Type III Recovery Sequence

Question 11

Correct answer: C. To prevent water from freezing as refrigerant pressure and saturation temperature fall

As refrigerant pressure falls, saturation temperature falls. Boiling refrigerant can cool tube surfaces enough to freeze water, so water must be circulated or removed according to the approved procedure.

A is incorrect: To increase ozone-depletion potential does not satisfy the governing Freeze prevention during recovery principle for this scenario. The correct condition is: To prevent water from freezing as refrigerant pressure and saturation temperature fall.
B is incorrect: To keep refrigerant from entering the recovery vessel does not satisfy the governing Freeze prevention during recovery principle for this scenario. The correct condition is: To prevent water from freezing as refrigerant pressure and saturation temperature fall.
D is incorrect: To make the purge unit discharge more refrigerant does not satisfy the governing Freeze prevention during recovery principle for this scenario. The correct condition is: To prevent water from freezing as refrigerant pressure and saturation temperature fall.

Topic: Freeze prevention during recovery
Suggested error code: FRZ
Review: 9.6 - Freeze Prevention During Recovery

Question 12

Correct answer: D. Drain them before refrigerant recovery

When a tube leak is suspected, draining the water sides prevents water from being driven through the failed tube into the low-pressure refrigerant circuit during recovery.

A is incorrect: Increase their pressure to the maximum pump head does not satisfy the governing Suspected tube leak and water-side draining principle for this scenario. The correct condition is: Drain them before refrigerant recovery.
B is incorrect: Add nitrogen to both water boxes does not satisfy the governing Suspected tube leak and water-side draining principle for this scenario. The correct condition is: Drain them before refrigerant recovery.
C is incorrect: Keep both pumps running regardless of the leak does not satisfy the governing Suspected tube leak and water-side draining principle for this scenario. The correct condition is: Drain them before refrigerant recovery.

Topic: Suspected tube leak and water-side draining
Suggested error code: FRZ
Review: 9.6 - Freeze Prevention During Recovery

Safety source: OSHA 29 CFR 1910.147 - The Control of Hazardous Energy

Question 13

Correct answer: A. 130°F

The current Type III examination value is 130°F before oil removal. Warming the oil helps refrigerant leave solution so it can be captured by recovery equipment.

B is incorrect: 85°F is not the current Type III oil-heating examination value; the module uses 130°F.
C is incorrect: 100°F is not the current Type III oil-heating examination value; the module uses 130°F.
D is incorrect: 115°F is not the current Type III oil-heating examination value; the module uses 130°F.

Topic: 130°F oil-heating exam value
Suggested error code: OIL
Review: 9.7 - Refrigerant in Oil

Exam-topic source: EPA - Section 608 Test Topics

Question 14

Correct answer: B. 5 psig

Current §82.156 permits the oil-change opening procedure after the appliance or isolated portion is evacuated or pressurized to no higher than 5 psig, or by the permitted system-receiver method.

A is incorrect: 0 psig is used only in specific low-pressure exceptions; it is not the normal Table 1 endpoint.
C is incorrect: 10 psig belongs to a different Type III context, such as leak testing or the traditional recovery-unit cutout, not this evacuation/opening condition.
D is incorrect: 15 psig belongs to a different Type III procedure; the current oil-change opening condition is no higher than 5 psig (or the permitted receiver procedure).

Topic: Current oil-change pressure condition
Suggested error code: REG
Review: 9.7 - Refrigerant in Oil

Current source: 40 CFR § 82.156 - Proper Evacuation of Refrigerant From Appliances; 40 CFR § 82.152 - Definitions

Question 15

Correct answer: C. Evaporator charging valve

The manufacturer-designated evaporator charging valve is the Type III charging connection. Physical elevation alone does not identify an approved service port.

A is incorrect: Condenser-water drain is a water-side service connection, not the manufacturer-designated refrigerant charging connection.
B is incorrect: Purge discharge line is associated with noncondensable removal, not the normal centrifugal-chiller charging connection.
D is incorrect: Rupture-disc outlet is an emergency overpressure-protection connection, not a normal charging point.

Topic: Evaporator charging valve
Suggested error code: CHG
Review: 9.8 - Recharging Low-Pressure Systems

Exam-topic source: EPA - Section 608 Test Topics

Question 16

Correct answer: D. To raise pressure and saturation temperature and reduce tube-freezing risk

Initial vapor charging raises chiller pressure and saturation temperature, reducing the severe flash-cooling and tube-freezing risk of adding bulk liquid directly into deep vacuum.

A is incorrect: To eliminate the need for evacuation does not satisfy the governing Initial vapor charging effect principle for this scenario. The correct condition is: To raise pressure and saturation temperature and reduce tube-freezing risk.
B is incorrect: To force noncondensables into the condenser water does not satisfy the governing Initial vapor charging effect principle for this scenario. The correct condition is: To raise pressure and saturation temperature and reduce tube-freezing risk.
C is incorrect: To lower the chiller pressure farther before liquid charging does not satisfy the governing Initial vapor charging effect principle for this scenario. The correct condition is: To raise pressure and saturation temperature and reduce tube-freezing risk.

Topic: Initial vapor charging effect
Suggested error code: CHG
Review: 9.8 - Recharging Low-Pressure Systems

Question 17

Correct answer: A. 25 mm Hg absolute

The current normal Section 608 Table 1 requirement for a low-pressure appliance is 25 mm Hg absolute.

B is incorrect: 4 in. Hg vacuum is associated with other pressure-category evacuation conditions, not the normal Type III low-pressure Table 1 endpoint.
C is incorrect: 10 in. Hg vacuum is associated with other pressure-category evacuation conditions, not the normal Type III low-pressure Table 1 endpoint.
D is incorrect: 15 in. Hg vacuum is associated with other pressure-category evacuation conditions, not the normal Type III low-pressure Table 1 endpoint.

Topic: Current Type III evacuation requirement
Suggested error code: EVA
Review: 9.9 - Type III Evacuation Requirements

Current source: 40 CFR § 82.156 - Proper Evacuation of Refrigerant From Appliances; EPA - Required Level of Evacuation of Appliances

Question 18

Correct answer: B. It does not change; both columns require 25 mm Hg absolute

The November 15, 1993 date refers to the manufacture/import date of the recovery/recycling equipment. The normal low-pressure endpoint remains 25 mm Hg absolute in both date columns.

A is incorrect: It changes from 25 mm Hg absolute to 4 in. Hg vacuum gives a different low-pressure endpoint, but the current low-pressure row is 25 mm Hg absolute in both date columns.
C is incorrect: It changes only when the appliance charge is below 200 lb gives a different low-pressure endpoint, but the current low-pressure row is 25 mm Hg absolute in both date columns.
D is incorrect: It depends on the chiller manufacture date assigns the date to the wrong equipment. November 15, 1993 refers to recovery/recycling equipment manufacture/import.

Topic: Recovery-equipment date and Type III endpoint
Suggested error code: EVA
Review: 9.9 - Type III Evacuation Requirements

Current source: 40 CFR § 82.156 - Proper Evacuation of Refrigerant From Appliances; EPA - Required Level of Evacuation of Appliances

Question 19

Correct answer: C. Remaining liquid refrigerant or refrigerant coming out of the oil

After the required recovery vacuum is reached and the system is isolated, pressure can rise because residual liquid refrigerant is still vaporizing or refrigerant is leaving oil. The condition must be evaluated and recovery resumed when required.

A is incorrect: The refrigerant has been reclaimed automatically is too absolute for the condition in this question. The correct answer depends on the specific Type III pressure, equipment, or service condition.
B is incorrect: The recovery vessel is necessarily empty is too absolute. Pressure rise can have more than one cause and must be interpreted in the context of recovery or post-service vacuum diagnosis.
D is incorrect: The chiller is ready to open without further evaluation does not satisfy the governing Pressure rebound after Type III recovery principle for this scenario. The correct condition is: Remaining liquid refrigerant or refrigerant coming out of the oil.

Topic: Pressure rebound after Type III recovery
Suggested error code: VAC
Review: 9.9 - Type III Evacuation Requirements

Exam-topic source: EPA - Section 608 Test Topics

Question 20

Correct answer: D. Removing the evaporator from the appliance

Current §82.152 includes removal of the compressor, condenser, evaporator, or auxiliary heat-exchange coil and an opening greater than 4 in² of flow area exposed more than 15 minutes in the major-repair definition.

A is incorrect: Replacing an external nameplate does not meet the current major-repair condition identified in the question. The correct answer matches the §82.152 definition.
B is incorrect: Tightening a water-box support bolt does not meet the current major-repair condition identified in the question. The correct answer matches the §82.152 definition.
C is incorrect: Replacing insulation on a water line does not meet the current major-repair condition identified in the question. The correct answer matches the §82.152 definition.

Topic: Major maintenance, service, or repair
Suggested error code: REG
Review: 9.9 - Type III Evacuation Requirements

Current source: 40 CFR § 82.156 - Proper Evacuation of Refrigerant From Appliances; 40 CFR § 82.152 - Definitions

Question 21

Correct answer: A. No higher than 0 psig

Under the limited current non-major provision, the low-pressure appliance is pressurized to no higher than 0 psig before opening when all regulatory conditions are satisfied.

B is incorrect: Exactly 5 psig belongs to the current oil-change provision, not this Type III condition.
C is incorrect: Exactly 10 psig belongs to a different Type III context, such as leak testing or the traditional recovery-unit cutout, not this evacuation/opening condition.
D is incorrect: 25 mm Hg gauge pressure belongs to a different procedure or uses the wrong pressure reference. The qualifying non-major opening condition is no higher than 0 psig when all regulatory conditions apply.

Topic: Qualifying non-major low-pressure opening
Suggested error code: REG
Review: 9.9 - Type III Evacuation Requirements

Current source: 40 CFR § 82.156 - Proper Evacuation of Refrigerant From Appliances; 40 CFR § 82.152 - Definitions

Question 22

Correct answer: B. To the lowest attainable level without substantial contamination, not above 0 psig

When a leak prevents the prescribed level, isolate where possible. The non-leaking portion still goes to the normal Table 1 level; the leaking portion goes to the lowest attainable level without substantial contamination, not above 0 psig.

A is incorrect: Only until the recovery machine first starts does not satisfy the governing Leaking-appliance evacuation exception principle for this scenario. The correct condition is: To the lowest attainable level without substantial contamination, not above 0 psig.
C is incorrect: To exactly 5 psig belongs to the current oil-change provision, not this Type III condition.
D is incorrect: No evacuation is required once a leak is confirmed incorrectly treats the existence of a leak as an exemption from recovery. A good-faith recovery effort and the lowest-attainable-level rule still apply.

Topic: Leaking-appliance evacuation exception
Suggested error code: REG
Review: 9.9 - Type III Evacuation Requirements

Current source: 40 CFR § 82.156 - Proper Evacuation of Refrigerant From Appliances; 40 CFR § 82.152 - Definitions

Question 23

Correct answer: C. It is a non-reclosing emergency overpressure device

A rupture disc is a non-reclosing emergency overpressure protection device and must not be used as a normal pressure-control or charging device.

A is incorrect: It is a normal pressure regulator that cycles open and closed incorrectly treats an emergency protection device as a normal operating control.
B is incorrect: It should be blocked during nitrogen testing does not satisfy the governing Rupture-disc protection principle for this scenario. The correct condition is: It is a non-reclosing emergency overpressure device.
D is incorrect: Every low-pressure chiller rupture disc is rated at 15 psig does not satisfy the governing Rupture-disc protection principle for this scenario. The correct condition is: It is a non-reclosing emergency overpressure device.

Topic: Rupture-disc protection
Suggested error code: SAF
Review: 9.10 - Type III Safety and Machinery Rooms

Question 24

Correct answer: D. A refrigerant monitor measures refrigerant in room air; an oxygen monitor measures oxygen, with less than 19.5% O₂ considered oxygen deficient

A refrigerant detector measures target refrigerant in room air, while an oxygen monitor measures oxygen concentration. Under OSHA general-industry terminology, less than 19.5% O₂ is oxygen deficient.

A is incorrect: A refrigerant monitor measures chiller pressure; an oxygen monitor measures water pressure does not satisfy the governing Refrigerant detection and oxygen deficiency principle for this scenario. The correct condition is: A refrigerant monitor measures refrigerant in room air; an oxygen monitor measures oxygen, with less than 19.5% O₂ considered oxygen deficient.
B is incorrect: An oxygen monitor replaces all refrigerant detection requirements does not satisfy the governing Refrigerant detection and oxygen deficiency principle for this scenario. The correct condition is: A refrigerant monitor measures refrigerant in room air; an oxygen monitor measures oxygen, with less than 19.5% O₂ considered oxygen deficient.
C is incorrect: A refrigerant monitor proves the room is safe whenever it reads zero is too absolute for the condition in this question. The correct answer depends on the specific Type III pressure, equipment, or service condition.

Topic: Refrigerant detection and oxygen deficiency
Suggested error code: SAF
Review: 9.10 - Type III Safety and Machinery Rooms

Safety source: OSHA 29 CFR 1910.146 - Permit-Required Confined Spaces

Question 25

Correct answer: A. Stored or static water pressure can remain and must be isolated, relieved, and verified before opening

Stopping a pump does not guarantee zero water pressure. Before opening a water box, isolate the water circuit, control applicable hazardous energy, relieve stored pressure, drain/vent as required, verify the condition, and use the approved lifting procedure.

B is incorrect: The water side is automatically at zero pressure ignores static head, trapped pressure, expansion pressure, and other stored energy that can remain after a pump stops.
C is incorrect: The cover bolts may be loosened to release any trapped pressure is unsafe; stored pressure must be relieved through the approved isolation/drain/vent procedure before cover bolts are loosened.
D is incorrect: The refrigerant side should be pressurized to 15 psig before opening the cover does not satisfy the governing Water-side stored energy and water-box safety principle for this scenario. The correct condition is: Stored or static water pressure can remain and must be isolated, relieved, and verified before opening.

Topic: Water-side stored energy and water-box safety
Suggested error code: WTR
Review: 9.10 - Type III Safety and Machinery Rooms

Safety source: OSHA 29 CFR 1910.147 - The Control of Hazardous Energy

Part L - Section 9.13 Practice Questions Set 2 Answers

Question 1

Correct answer: B. Type II because the refrigerant is not in the low-pressure category

A refrigerant with a liquid-phase saturation pressure of 190 psia at 104°F is not in the low-pressure category. A centrifugal compressor does not force Type III classification; the refrigerant pressure category controls.

A is incorrect: Type III because every centrifugal chiller is low pressure does not satisfy the governing Pressure category and certification type principle for this scenario. The correct condition is: Type II because the refrigerant is not in the low-pressure category.
C is incorrect: Type I because a centrifugal compressor is factory assembled applies to qualifying small appliances, not the low-pressure Type III condition described here.
D is incorrect: No Section 608 certification can apply to a chiller does not satisfy the governing Pressure category and certification type principle for this scenario. The correct condition is: Type II because the refrigerant is not in the low-pressure category.

Topic: Pressure category and certification type
Suggested error code: CLS
Review: 9.1 - Low-Pressure Appliance Fundamentals

Current source: 40 CFR § 82.152 - Definitions

Question 2

Correct answer: C. Water flows through the heat-exchanger tubes while refrigerant occupies the shell side

In the conventional shell-and-tube arrangement used in this module, water flows through the heat-exchanger tubes while refrigerant occupies the shell side. The tube wall separates the water and refrigerant.

A is incorrect: Refrigerant always flows through both water boxes is too absolute for the condition in this question. The correct answer depends on the specific Type III pressure, equipment, or service condition.
B is incorrect: Water and refrigerant are intentionally mixed in the evaporator does not satisfy the governing Shell-and-tube chiller construction principle for this scenario. The correct condition is: Water flows through the heat-exchanger tubes while refrigerant occupies the shell side.
D is incorrect: The purge unit separates chilled water from condenser water does not satisfy the governing Shell-and-tube chiller construction principle for this scenario. The correct condition is: Water flows through the heat-exchanger tubes while refrigerant occupies the shell side.

Topic: Shell-and-tube chiller construction
Suggested error code: CMP
Review: 9.2 - Low-Pressure Chiller Components

Question 3

Correct answer: D. Air may be leaking into the chiller

A significant increase in purge operation suggests continued air infiltration through a leak. The purge removes noncondensables but does not repair the leak.

A is incorrect: The chiller has become a very-high-pressure appliance does not satisfy the governing Frequent purging as an air-leak clue principle for this scenario. The correct condition is: Air may be leaking into the chiller.
B is incorrect: The evaporator charging valve is oversized does not satisfy the governing Frequent purging as an air-leak clue principle for this scenario. The correct condition is: Air may be leaking into the chiller.
C is incorrect: The recovery cylinder is overfilled does not satisfy the governing Frequent purging as an air-leak clue principle for this scenario. The correct condition is: Air may be leaking into the chiller.

Topic: Frequent purging as an air-leak clue
Suggested error code: PUR
Review: 9.3 - Air Moisture and Purge Units

Question 4

Correct answer: A. A possible tube or water-side leak

Unusually large moisture removal by the purge system should prompt investigation for a possible heat-exchanger tube or other water-side leak.

B is incorrect: A recovery vessel with too little refrigerant does not satisfy the governing Moisture as a tube-leak clue principle for this scenario. The correct condition is: A possible tube or water-side leak.
C is incorrect: An undersized refrigerant cylinder color label does not satisfy the governing Moisture as a tube-leak clue principle for this scenario. The correct condition is: A possible tube or water-side leak.
D is incorrect: A compressor operating above its motor voltage does not satisfy the governing Moisture as a tube-leak clue principle for this scenario. The correct condition is: A possible tube or water-side leak.

Topic: Moisture as a tube-leak clue
Suggested error code: PUR
Review: 9.3 - Air Moisture and Purge Units

Question 5

Correct answer: B. It can reverse the leak direction so refrigerant or test gas moves outward at the leak

Raising refrigerant-side pressure slightly above atmosphere can reverse the pressure differential so refrigerant or approved test gas moves outward at the leak, making it easier to locate.

A is incorrect: It makes air leak inward faster does not satisfy the governing Leak-direction reversal for leak detection principle for this scenario. The correct condition is: It can reverse the leak direction so refrigerant or test gas moves outward at the leak.
C is incorrect: It eliminates the need for a leak detector does not satisfy the governing Leak-direction reversal for leak detection principle for this scenario. The correct condition is: It can reverse the leak direction so refrigerant or test gas moves outward at the leak.
D is incorrect: It converts a tube leak into an electrical fault does not satisfy the governing Leak-direction reversal for leak detection principle for this scenario. The correct condition is: It can reverse the leak direction so refrigerant or test gas moves outward at the leak.

Topic: Leak-direction reversal for leak detection
Suggested error code: LKD
Review: 9.4 - Low-Pressure Leak Detection and Pressurization

Question 6

Correct answer: C. Regulated nitrogen with gauges and appropriate downstream pressure protection

The Type III exam-preparation maximum for pressurizing a charged low-pressure chiller for leak testing is 10 psig. It is a ceiling, and a lower manufacturer limit controls in field work.

A is incorrect: Nitrogen cylinder connected directly with no regulator does not satisfy the governing Type III leak-test pressure maximum principle for this scenario. The correct condition is: Regulated nitrogen with gauges and appropriate downstream pressure protection.
B is incorrect: Oxygen cylinder connected through a manifold is not an acceptable refrigerant-system pressure-test gas and can create serious safety hazards; regulated dry nitrogen is used only where permitted.
D is incorrect: Compressed shop air connected until the relief device lifts is not an acceptable refrigerant-system pressure-test gas and can create serious safety hazards; regulated dry nitrogen is used only where permitted.

Topic: Type III leak-test pressure maximum
Suggested error code: NUM
Review: 9.4 - Low-Pressure Leak Detection and Pressurization

Question 7

Correct answer: D. Shaft seal

The shaft seal is a classic leak location on an open-drive compressor because the rotating shaft penetrates the refrigerant-containing housing.

A is incorrect: Condenser-water pump impeller only does not satisfy the governing Open-drive shaft-seal leak location principle for this scenario. The correct condition is: Shaft seal.
B is incorrect: Cooling-tower fan blade does not satisfy the governing Open-drive shaft-seal leak location principle for this scenario. The correct condition is: Shaft seal.
C is incorrect: Chilled-water balancing valve only does not satisfy the governing Open-drive shaft-seal leak location principle for this scenario. The correct condition is: Shaft seal.

Topic: Open-drive shaft-seal leak location
Suggested error code: LKD
Review: 9.4 - Low-Pressure Leak Detection and Pressurization

Question 8

Correct answer: A. About 100 lb of refrigerant vapor may still remain in the representative example

The classic Type III example illustrates that about 100 lb of refrigerant vapor can remain in an average 350-ton R-11 chiller at 0 psig after accessible liquid is removed. It is an example, not a universal quantity.

B is incorrect: No refrigerant can remain at 0 psig does not match the representative Type III example, which uses approximately 100 lb of remaining vapor.
C is incorrect: The recovery vessel must contain exactly 100 lb does not satisfy the governing Classic remaining-vapor example principle for this scenario. The correct condition is: About 100 lb of refrigerant vapor may still remain in the representative example.
D is incorrect: The chiller may now be vented because only vapor remains conflicts with refrigerant-conservation requirements; remaining refrigerant must be recovered rather than intentionally vented.

Topic: Classic remaining-vapor example
Suggested error code: REC
Review: 9.5 - Type III Recovery Sequence

Question 9

Correct answer: B. Insufficient cooling-water flow through the recovery-machine condenser

A recovery-unit high-pressure trip during vapor recovery can result from inadequate heat rejection, including insufficient cooling-water flow through the recovery-machine condenser.

A is incorrect: Whether the chiller is classified as Type I applies to qualifying small appliances, not the low-pressure Type III condition described here.
C is incorrect: Whether the evaporator water box is painted does not satisfy the governing Recovery-machine high-pressure cutout diagnosis principle for this scenario. The correct condition is: Insufficient cooling-water flow through the recovery-machine condenser.
D is incorrect: Whether the purge unit has been removed does not satisfy the governing Recovery-machine high-pressure cutout diagnosis principle for this scenario. The correct condition is: Insufficient cooling-water flow through the recovery-machine condenser.

Topic: Recovery-machine high-pressure cutout diagnosis
Suggested error code: REC
Review: 9.5 - Type III Recovery Sequence

Question 10

Correct answer: C. It is a recovery-vessel protection value and not a universal chiller relief rating

The traditional 15 psig Type III value belongs to the low-pressure recovery-vessel rupture disc and must not be transferred to the chiller relief device or evacuation endpoint.

A is incorrect: It is the normal final evacuation pressure of the chiller does not satisfy the governing Low-pressure recovery-vessel rupture disc principle for this scenario. The correct condition is: It is a recovery-vessel protection value and not a universal chiller relief rating.
B is incorrect: It is the oil-change opening pressure does not satisfy the governing Low-pressure recovery-vessel rupture disc principle for this scenario. The correct condition is: It is a recovery-vessel protection value and not a universal chiller relief rating.
D is incorrect: It is the pressure at which every vapor charge must switch to liquid does not satisfy the governing Low-pressure recovery-vessel rupture disc principle for this scenario. The correct condition is: It is a recovery-vessel protection value and not a universal chiller relief rating.

Topic: Low-pressure recovery-vessel rupture disc
Suggested error code: NUM
Review: 9.5 - Type III Recovery Sequence

Question 11

Correct answer: D. Lower refrigerant pressure lowers saturation temperature, so boiling refrigerant can cool tube surfaces enough to freeze water

A is incorrect: Lower pressure always raises the refrigerant saturation temperature is too absolute for the condition in this question. The correct answer depends on the specific Type III pressure, equipment, or service condition.
B is incorrect: Vacuum causes water to generate heat inside the tubes does not satisfy the governing Freeze prevention during recovery principle for this scenario. The correct condition is: Lower refrigerant pressure lowers saturation temperature, so boiling refrigerant can cool tube surfaces enough to freeze water.
C is incorrect: The recovery machine stops removing latent heat does not satisfy the governing Freeze prevention during recovery principle for this scenario. The correct condition is: Lower refrigerant pressure lowers saturation temperature, so boiling refrigerant can cool tube surfaces enough to freeze water.

Topic: Freeze prevention during recovery
Suggested error code: FRZ
Review: 9.6 - Freeze Prevention During Recovery

Question 12

Correct answer: A. Actual water flow through the required circuit must be verified

A running pump motor does not prove adequate water flow. The required water flow must actually be established to provide heat to cold tube surfaces and limit freeze-up.

B is incorrect: The recovery vessel must be exactly 15 psig does not satisfy the governing Verify water flow for freeze prevention principle for this scenario. The correct condition is: Actual water flow through the required circuit must be verified.
C is incorrect: The purge unit must be disconnected does not satisfy the governing Verify water flow for freeze prevention principle for this scenario. The correct condition is: Actual water flow through the required circuit must be verified.
D is incorrect: All service valves must be closed does not satisfy the governing Verify water flow for freeze prevention principle for this scenario. The correct condition is: Actual water flow through the required circuit must be verified.

Topic: Verify water flow for freeze prevention
Suggested error code: FRZ
Review: 9.6 - Freeze Prevention During Recovery

Question 13

Correct answer: B. Rapid boiling of refrigerant out of oil when pressure is suddenly reduced

Oil foaming is caused by dissolved refrigerant rapidly boiling out of the lubricant after a pressure reduction.

A is incorrect: Condenser water mixing with nitrogen in the recovery vessel does not describe oil foaming. Foaming is caused by dissolved refrigerant rapidly boiling out of the oil.
C is incorrect: The oil reaching 25 mm Hg absolute does not describe oil foaming. Foaming is caused by dissolved refrigerant rapidly boiling out of the oil.
D is incorrect: A refrigerant monitor sensing oxygen does not describe oil foaming. Foaming is caused by dissolved refrigerant rapidly boiling out of the oil.

Topic: Oil foaming
Suggested error code: OIL
Review: 9.7 - Refrigerant in Oil

Question 14

Correct answer: C. To reduce refrigerant remaining in the oil and minimize release during removal

The current Type III examination value is 130°F before oil removal. Warming the oil helps refrigerant leave solution so it can be captured by recovery equipment.

A is incorrect: To increase refrigerant venting during oil handling conflicts with refrigerant-conservation requirements; remaining refrigerant must be recovered rather than intentionally vented.
B is incorrect: To raise water-box pressure does not satisfy the governing 130°F oil-heating exam value principle for this scenario. The correct condition is: To reduce refrigerant remaining in the oil and minimize release during removal.
D is incorrect: To eliminate the need for the final recovery endpoint does not satisfy the governing 130°F oil-heating exam value principle for this scenario. The correct condition is: To reduce refrigerant remaining in the oil and minimize release during removal.

Topic: 130°F oil-heating exam value
Suggested error code: OIL
Review: 9.7 - Refrigerant in Oil

Exam-topic source: EPA - Section 608 Test Topics

Question 15

Correct answer: D. It raises pressure and saturation temperature, reducing freeze risk

Initial vapor charging raises chiller pressure and saturation temperature, reducing the severe flash-cooling and tube-freezing risk of adding bulk liquid directly into deep vacuum.

A is incorrect: It lowers pressure and lowers saturation temperature reverses the saturation pressure-temperature relationship used here. Raising pressure raises saturation temperature.
B is incorrect: It removes moisture without a vacuum pump does not satisfy the governing Initial vapor charging effect principle for this scenario. The correct condition is: It raises pressure and saturation temperature, reducing freeze risk.
C is incorrect: It forces liquid refrigerant out through the rupture disc is an emergency overpressure-protection connection, not a normal charging point.

Topic: Initial vapor charging effect
Suggested error code: CHG
Review: 9.8 - Recharging Low-Pressure Systems

Question 16

Correct answer: A. Use the manufacturer-designated evaporator charging valve

The manufacturer-designated evaporator charging valve is the Type III charging connection. Physical elevation alone does not identify an approved service port.

B is incorrect: Use whichever fitting is physically closest to the floor does not satisfy the governing Evaporator charging valve principle for this scenario. The correct condition is: Use the manufacturer-designated evaporator charging valve.
C is incorrect: Use the rupture-disc outlet because it is connected to the refrigerant space is an emergency overpressure-protection connection, not a normal charging point.
D is incorrect: Use a water-box drain because it is a low point is a water-side service connection, not the manufacturer-designated refrigerant charging connection.

Topic: Evaporator charging valve
Suggested error code: CHG
Review: 9.8 - Recharging Low-Pressure Systems

Exam-topic source: EPA - Section 608 Test Topics

Question 17

Correct answer: B. 25 mm Hg absolute

The Type III value is 25 mm Hg absolute, an absolute pressure near 0.98 in. Hg absolute. It is not a 25-in. Hg vacuum reading or a positive gauge pressure.

A is incorrect: 25 psig is positive gauge pressure and is not the required low-pressure evacuation condition.
C is incorrect: 25 in. Hg vacuum confuses inches of mercury vacuum with the current low-pressure requirement of 25 mm Hg absolute.
D is incorrect: 25 mm Hg above atmospheric pressure does not satisfy the governing Meaning of 25 mm Hg absolute principle for this scenario. The correct condition is: 25 mm Hg absolute.

Topic: Meaning of 25 mm Hg absolute
Suggested error code: UNIT
Review: 9.9 - Type III Evacuation Requirements

Current source: 40 CFR § 82.156 - Proper Evacuation of Refrigerant From Appliances; EPA - Required Level of Evacuation of Appliances

Question 18

Correct answer: C. Both use 25 mm Hg absolute

The normal low-pressure Table 1 endpoint is 25 mm Hg absolute both below and at/above 200 lb. The 200-lb boundary changes some Type II rows, not the Type III low-pressure row.

A is incorrect: Only the 500-lb chiller uses 25 mm Hg absolute incorrectly imports the 200-lb distinction from other pressure-category rows. The normal Type III low-pressure endpoint remains 25 mm Hg absolute.
B is incorrect: The 150-lb chiller uses 4 in. Hg vacuum incorrectly imports the 200-lb distinction from other pressure-category rows. The normal Type III low-pressure endpoint remains 25 mm Hg absolute.
D is incorrect: The 200-lb boundary changes the Type III endpoint to 15 in. Hg vacuum incorrectly imports the 200-lb distinction from other pressure-category rows. The normal Type III low-pressure endpoint remains 25 mm Hg absolute.

Topic: Charge size and Type III endpoint
Suggested error code: EVA
Review: 9.9 - Type III Evacuation Requirements

Current source: 40 CFR § 82.156 - Proper Evacuation of Refrigerant From Appliances; EPA - Required Level of Evacuation of Appliances

Question 19

Correct answer: D. It is major maintenance, service, or repair

A is incorrect: It is never major unless the compressor is removed does not meet the current major-repair condition identified in the question. The correct answer matches the §82.152 definition.
B is incorrect: It is automatically a Type I repair applies to qualifying small appliances, not the low-pressure Type III condition described here.
C is incorrect: It is exempt from refrigerant recovery does not meet the current major-repair condition identified in the question. The correct answer matches the §82.152 definition.

Topic: Major maintenance, service, or repair
Suggested error code: REG
Review: 9.9 - Type III Evacuation Requirements

Current source: 40 CFR § 82.156 - Proper Evacuation of Refrigerant From Appliances; 40 CFR § 82.152 - Definitions

Question 20

Correct answer: A. A method requiring subsequent purging, such as nitrogen, must not be used for that procedure

For the qualifying non-major low-pressure procedure, a refrigerant boiling at or below 85°F at standard atmospheric pressure cannot be pressurized by a method, such as nitrogen, that requires subsequent purging.

B is incorrect: Nitrogen must always be used to raise the appliance to 10 psig belongs to a different Type III context, such as leak testing or the traditional recovery-unit cutout, not this evacuation/opening condition.
C is incorrect: Compressed air is preferred over heat is not an acceptable refrigerant-system pressure-test gas and can create serious safety hazards; regulated dry nitrogen is used only where permitted.
D is incorrect: The appliance may be opened at 5 psig belongs to the current oil-change provision, not this Type III condition.

Topic: Nitrogen restriction in qualifying non-major work
Suggested error code: REG
Review: 9.9 - Type III Evacuation Requirements

Current source: 40 CFR § 82.156 - Proper Evacuation of Refrigerant From Appliances; 40 CFR § 82.152 - Definitions

Question 21

Correct answer: B. Evacuate the non-leaking portion to the normal Table 1 level, and take the leaking portion to the lowest attainable level without substantial contamination, not above 0 psig

A is incorrect: Leave both portions at 0 psig because one component leaks incorrectly treats the existence of a leak as an exemption from recovery. A good-faith recovery effort and the lowest-attainable-level rule still apply.
C is incorrect: Pressurize both portions to 10 psig before opening belongs to a different Type III context, such as leak testing or the traditional recovery-unit cutout, not this evacuation/opening condition.
D is incorrect: Vent both portions because the leak prevents normal recovery conflicts with refrigerant-conservation requirements; remaining refrigerant must be recovered rather than intentionally vented.

Topic: Leaking-appliance evacuation exception
Suggested error code: REG
Review: 9.9 - Type III Evacuation Requirements

Current source: 40 CFR § 82.156 - Proper Evacuation of Refrigerant From Appliances; 40 CFR § 82.152 - Definitions

Question 22

Correct answer: C. Additional refrigerant may still be vaporizing from liquid or oil, so the condition must be evaluated

A is incorrect: The pressure increase proves an external leak is too absolute. Pressure rise can have more than one cause and must be interpreted in the context of recovery or post-service vacuum diagnosis.
B is incorrect: The pressure increase proves the chiller is empty is too absolute. Pressure rise can have more than one cause and must be interpreted in the context of recovery or post-service vacuum diagnosis.
D is incorrect: The recovery-machine condenser must be replaced immediately does not satisfy the governing Pressure rebound after Type III recovery principle for this scenario. The correct condition is: Additional refrigerant may still be vaporizing from liquid or oil, so the condition must be evaluated.

Topic: Pressure rebound after Type III recovery
Suggested error code: VAC
Review: 9.9 - Type III Evacuation Requirements

Exam-topic source: EPA - Section 608 Test Topics

Question 23

Correct answer: D. The downstream valve can restrict or interfere with the required relief flow

Two ordinary relief valves should not simply be installed in series as redundant protection because the downstream valve can interfere with the required relief path. Approved engineered relief arrangements are different.

A is incorrect: Two valves in series always lower pressure below absolute zero is too absolute for the condition in this question. The correct answer depends on the specific Type III pressure, equipment, or service condition.
B is incorrect: The arrangement converts both valves to purge units does not satisfy the governing Pressure-relief arrangement principle for this scenario. The correct condition is: The downstream valve can restrict or interfere with the required relief flow.
C is incorrect: The arrangement is required on every low-pressure chiller does not satisfy the governing Pressure-relief arrangement principle for this scenario. The correct condition is: The downstream valve can restrict or interfere with the required relief flow.

Topic: Pressure-relief arrangement
Suggested error code: SAF
Review: 9.10 - Type III Safety and Machinery Rooms

Question 24

Correct answer: A. 19.4% oxygen

B is incorrect: 20.9% oxygen does not satisfy the governing Refrigerant detection and oxygen deficiency principle for this scenario. The correct condition is: 19.4% oxygen.
C is incorrect: 20.0% oxygen does not satisfy the governing Refrigerant detection and oxygen deficiency principle for this scenario. The correct condition is: 19.4% oxygen.
D is incorrect: 19.5% oxygen or higher does not meet the oxygen-deficient definition, which applies below 19.5% O₂.

Topic: Refrigerant detection and oxygen deficiency
Suggested error code: SAF
Review: 9.10 - Type III Safety and Machinery Rooms

Safety source: OSHA 29 CFR 1910.146 - Permit-Required Confined Spaces

Question 25

Correct answer: B. Isolate the circuit, control applicable hazardous energy, relieve pressure, drain or vent as required, verify the condition, then open using the approved lifting procedure

After the water side is safely isolated, depressurized, and drained, a large water-box cover can still be very heavy and may require rated lifting, rigging, and support equipment.

A is incorrect: Shut the pump off and immediately loosen the lowest bolts is unsafe; stored pressure must be relieved through the approved isolation/drain/vent procedure before cover bolts are loosened.
C is incorrect: Pressurize the refrigerant side to 15 psig to hold the cover in place does not satisfy the governing Water-box cover lifting hazard principle for this scenario. The correct condition is: Isolate the circuit, control applicable hazardous energy, relieve pressure, drain or vent as required, verify the condition, then open using the approved lifting procedure.
D is incorrect: Run the pump while removing the cover so water cannot stagnate does not satisfy the governing Water-box cover lifting hazard principle for this scenario. The correct condition is: Isolate the circuit, control applicable hazardous energy, relieve pressure, drain or vent as required, verify the condition, then open using the approved lifting procedure.

Topic: Water-box cover lifting hazard
Suggested error code: WTR
Review: 9.10 - Type III Safety and Machinery Rooms

Safety source: OSHA 29 CFR 1910.147 - The Control of Hazardous Energy

Part M - Section 9.14 Practice Questions Set 3 Answers

Question 1

Correct answer: C. The refrigerant pressure category controls; a centrifugal compressor does not by itself make the appliance Type III

Current Section 608 defines a low-pressure appliance by refrigerant liquid-phase saturation pressure below 45 psia at 104°F. This pressure category is the basis for Type III scope.

A is incorrect: The compressor type alone determines the certification type does not satisfy the governing Low-pressure appliance classification principle for this scenario. The correct condition is: The refrigerant pressure category controls; a centrifugal compressor does not by itself make the appliance Type III.
B is incorrect: Any machine called a chiller is Type III does not satisfy the governing Low-pressure appliance classification principle for this scenario. The correct condition is: The refrigerant pressure category controls; a centrifugal compressor does not by itself make the appliance Type III.
D is incorrect: Only the refrigerant charge size determines the type does not satisfy the governing Low-pressure appliance classification principle for this scenario. The correct condition is: The refrigerant pressure category controls; a centrifugal compressor does not by itself make the appliance Type III.

Topic: Low-pressure appliance classification
Suggested error code: CLS
Review: 9.1 - Low-Pressure Appliance Fundamentals

Current source: 40 CFR § 82.152 - Definitions

Question 2

Correct answer: D. Refrigerant can leak outward

When local refrigerant-side pressure is above atmospheric pressure, refrigerant can leak outward. Leak direction follows the local pressure difference.

A is incorrect: Air must always leak inward regardless of local pressure is too absolute for the condition in this question. The correct answer depends on the specific Type III pressure, equipment, or service condition.
B is incorrect: Only condenser water can move through the leak does not satisfy the governing Positive-pressure leak direction principle for this scenario. The correct condition is: Refrigerant can leak outward.
C is incorrect: No flow can occur because the appliance is Type III does not satisfy the governing Positive-pressure leak direction principle for this scenario. The correct condition is: Refrigerant can leak outward.

Topic: Positive-pressure leak direction
Suggested error code: PRS
Review: 9.1 - Low-Pressure Appliance Fundamentals

Question 3

Correct answer: A. A purge unit removes noncondensables during chiller operation/service, while a recovery machine removes refrigerant from the appliance

A purge unit removes noncondensables from the operating/service refrigerant system while minimizing refrigerant loss. A recovery machine removes refrigerant from the appliance during service or disposal.

B is incorrect: A purge unit removes the entire refrigerant charge; a recovery machine removes only air does not satisfy the governing Purge unit versus recovery machine principle for this scenario. The correct condition is: A purge unit removes noncondensables during chiller operation/service, while a recovery machine removes refrigerant from the appliance.
C is incorrect: Both devices are only water pumps does not satisfy the governing Purge unit versus recovery machine principle for this scenario. The correct condition is: A purge unit removes noncondensables during chiller operation/service, while a recovery machine removes refrigerant from the appliance.
D is incorrect: A recovery machine is part of the normal centrifugal compressor does not satisfy the governing Purge unit versus recovery machine principle for this scenario. The correct condition is: A purge unit removes noncondensables during chiller operation/service, while a recovery machine removes refrigerant from the appliance.

Topic: Purge unit versus recovery machine
Suggested error code: CMP
Review: 9.3 - Air Moisture and Purge Units

Question 4

Correct answer: B. Condenser-water temperature, flow, and fouling conditions

Noncondensables can raise condenser pressure, but condenser-water temperature, flow, and fouling also affect heat rejection. High head pressure is therefore not proof of noncondensables by itself.

A is incorrect: Only the color of the recovery cylinder does not satisfy the governing High condenser pressure differential diagnosis principle for this scenario. The correct condition is: Condenser-water temperature, flow, and fouling conditions.
C is incorrect: Whether the chiller has a rupture disc does not satisfy the governing High condenser pressure differential diagnosis principle for this scenario. The correct condition is: Condenser-water temperature, flow, and fouling conditions.
D is incorrect: Whether the oil heater is exactly 130°F does not satisfy the governing High condenser pressure differential diagnosis principle for this scenario. The correct condition is: Condenser-water temperature, flow, and fouling conditions.

Topic: High condenser pressure differential diagnosis
Suggested error code: PUR
Review: 9.3 - Air Moisture and Purge Units

Question 5

Correct answer: C. The manufacturer’s lower allowable limit

The 10 psig figure is an exam-preparation maximum, not permission to exceed a lower manufacturer limit. The equipment-specific lower allowable pressure controls in actual service.

A is incorrect: 10 psig because exam values always override equipment instructions is too absolute for the condition in this question. The correct answer depends on the specific Type III pressure, equipment, or service condition.
B is incorrect: 15 psig because it is a recovery-vessel value does not satisfy the governing Manufacturer limit versus exam maximum principle for this scenario. The correct condition is: The manufacturer’s lower allowable limit.
D is incorrect: Any pressure below the nitrogen-cylinder pressure does not satisfy the governing Manufacturer limit versus exam maximum principle for this scenario. The correct condition is: The manufacturer’s lower allowable limit.

Topic: Manufacturer limit versus exam maximum
Suggested error code: LKD
Review: 9.4 - Low-Pressure Leak Detection and Pressurization

Question 6

Correct answer: D. Use a hydrostatic tube test kit

The traditional water-box check is performed after draining the water, with a compatible refrigerant detector used at the drain opening.

A is incorrect: Probe the purge discharge with an oxygen sensor does not satisfy the governing Water-box leak checking principle for this scenario. The correct condition is: Use a hydrostatic tube test kit.
B is incorrect: Pressurize the chiller with compressed air to 25 psig does not satisfy the governing Water-box leak checking principle for this scenario. The correct condition is: Use a hydrostatic tube test kit.
C is incorrect: Loosen the water-box cover while the pump is running does not satisfy the governing Water-box leak checking principle for this scenario. The correct condition is: Use a hydrostatic tube test kit.

Topic: Water-box leak checking
Suggested error code: LKD
Review: 9.4 - Low-Pressure Leak Detection and Pressurization

Safety source: OSHA 29 CFR 1910.147 - The Control of Hazardous Energy

Question 7

Correct answer: A. Liquid recovery removes a large refrigerant mass more quickly

Bulk liquid is removed first because it contains much greater refrigerant mass per unit volume, making liquid-first recovery faster and more efficient.

B is incorrect: Vapor recovery is prohibited on low-pressure appliances is slower when accessible bulk liquid can be removed first; liquid-first recovery removes refrigerant mass more efficiently.
C is incorrect: Liquid recovery raises the chiller pressure to 15 psig does not satisfy the governing Liquid-first recovery principle for this scenario. The correct condition is: Liquid recovery removes a large refrigerant mass more quickly.
D is incorrect: Removing liquid eliminates all refrigerant in the oil is not the refrigerant phase that should be removed first when accessible bulk liquid is present.

Topic: Liquid-first recovery
Suggested error code: REC
Review: 9.5 - Type III Recovery Sequence

Question 8

Correct answer: B. Chiller water pumps, recovery compressor, and recovery-condenser cooling water

In the traditional normal recovery arrangement, chiller water pumps, the recovery compressor, and recovery-condenser cooling water operate as required to control freeze risk and recovery discharge pressure.

A is incorrect: Purge unit only does not satisfy the governing Normal Type III recovery operating condition principle for this scenario. The correct condition is: Chiller water pumps, recovery compressor, and recovery-condenser cooling water.
C is incorrect: Chiller compressor with all water pumps off does not satisfy the governing Normal Type III recovery operating condition principle for this scenario. The correct condition is: Chiller water pumps, recovery compressor, and recovery-condenser cooling water.
D is incorrect: Rupture disc heater and oxygen supply does not satisfy the governing Normal Type III recovery operating condition principle for this scenario. The correct condition is: Chiller water pumps, recovery compressor, and recovery-condenser cooling water.

Topic: Normal Type III recovery operating condition
Suggested error code: REC
Review: 9.5 - Type III Recovery Sequence

Question 9

Correct answer: C. The recovery-unit cutout is 10 psig and the recovery-vessel rupture disc is 15 psig

The traditional low-pressure recovery-unit high-pressure cutout is 10 psig, and the traditional low-pressure recovery-vessel rupture disc is 15 psig. These are equipment-protection values in different components.

A is incorrect: The recovery-unit cutout is 15 psig and the vessel disc is 10 psig is the traditional recovery-unit high-pressure cutout, not the recovery-vessel rupture-disc value.
B is incorrect: Both are 25 mm Hg absolute assigns the 10 psig and 15 psig values to the wrong component or procedure. The correct pairing is given in the correct answer.
D is incorrect: Both are universal chiller relief settings assigns the 10 psig and 15 psig values to the wrong component or procedure. The correct pairing is given in the correct answer.

Topic: Recovery-unit cutout versus recovery-vessel rupture disc
Suggested error code: NUM
Review: 9.5 - Type III Recovery Sequence

Question 10

Correct answer: D. To prevent water from being driven into the low-pressure refrigerant circuit, where it can contaminate the system and contribute to freeze damage

When a tube leak is suspected, draining the water sides prevents water from being driven through the failed tube into the low-pressure refrigerant circuit during recovery.

A is incorrect: To increase water pressure across the failed tube does not satisfy the governing Suspected tube leak and water-side draining principle for this scenario. The correct condition is: To prevent water from being driven into the low-pressure refrigerant circuit, where it can contaminate the system and contribute to freeze damage.
B is incorrect: To make the refrigerant boil at a higher pressure does not satisfy the governing Suspected tube leak and water-side draining principle for this scenario. The correct condition is: To prevent water from being driven into the low-pressure refrigerant circuit, where it can contaminate the system and contribute to freeze damage.
C is incorrect: To allow the recovery unit to bypass its cutout does not satisfy the governing Suspected tube leak and water-side draining principle for this scenario. The correct condition is: To prevent water from being driven into the low-pressure refrigerant circuit, where it can contaminate the system and contribute to freeze damage.

Topic: Suspected tube leak and water-side draining
Suggested error code: FRZ
Review: 9.6 - Freeze Prevention During Recovery

Safety source: OSHA 29 CFR 1910.147 - The Control of Hazardous Energy

Question 11

Correct answer: A. To drive refrigerant out of the oil so it can be recovered before oil removal

The current Type III examination value is 130°F before oil removal. Warming the oil helps refrigerant leave solution so it can be captured by recovery equipment.

B is incorrect: To keep more refrigerant dissolved in the oil does not satisfy the governing 130°F oil-heating exam value principle for this scenario. The correct condition is: To drive refrigerant out of the oil so it can be recovered before oil removal.
C is incorrect: To raise the condenser-water temperature does not satisfy the governing 130°F oil-heating exam value principle for this scenario. The correct condition is: To drive refrigerant out of the oil so it can be recovered before oil removal.
D is incorrect: To eliminate the Section 608 evacuation requirement does not satisfy the governing 130°F oil-heating exam value principle for this scenario. The correct condition is: To drive refrigerant out of the oil so it can be recovered before oil removal.

Topic: 130°F oil-heating exam value
Suggested error code: OIL
Review: 9.7 - Refrigerant in Oil

Exam-topic source: EPA - Section 608 Test Topics

Question 12

Correct answer: B. The appliance must still satisfy the applicable recovery/evacuation requirement

Oil removal is not proof that refrigerant recovery is complete. The appliance must still meet the applicable evacuation/recovery condition, and residual refrigerant can remain in vapor spaces or oil.

A is incorrect: Oil removal automatically proves refrigerant recovery is complete incorrectly treats oil removal as the end of refrigerant recovery. The applicable recovery/evacuation requirement still controls.
C is incorrect: Any remaining refrigerant may be vented because the oil is gone conflicts with refrigerant-conservation requirements; remaining refrigerant must be recovered rather than intentionally vented.
D is incorrect: The system must be pressurized to 15 psig before further recovery does not satisfy the governing Oil removal versus recovery completion principle for this scenario. The correct condition is: The appliance must still satisfy the applicable recovery/evacuation requirement.

Topic: Oil removal versus recovery completion
Suggested error code: OIL
Review: 9.7 - Refrigerant in Oil

Question 13

Correct answer: C. Use an approved procedure to meter or vaporize the refrigerant as needed so vapor enters the deeply evacuated chiller initially

A blend may need to be withdrawn from its supply cylinder as liquid, but approved metering or vaporization is used as needed so that the deeply evacuated chiller initially receives vapor and avoids freeze damage.

A is incorrect: Send unrestricted liquid directly into the chiller does not satisfy the governing Blend handling during Type III charging principle for this scenario. The correct condition is: Use an approved procedure to meter or vaporize the refrigerant as needed so vapor enters the deeply evacuated chiller initially.
B is incorrect: Mix the liquid refrigerant with compressed air does not satisfy the governing Blend handling during Type III charging principle for this scenario. The correct condition is: Use an approved procedure to meter or vaporize the refrigerant as needed so vapor enters the deeply evacuated chiller initially.
D is incorrect: Skip the vapor-first requirement whenever a blend is used is too absolute for the condition in this question. The correct answer depends on the specific Type III pressure, equipment, or service condition.

Topic: Blend handling during Type III charging
Suggested error code: CHG
Review: 9.8 - Recharging Low-Pressure Systems

Question 14

Correct answer: D. When the manufacturer-approved procedure indicates the required pressure, temperature, water, and system conditions are safe

There is no universal switch pressure. Controlled liquid charging begins only when the manufacturer-approved procedure indicates that pressure, saturation temperature, water condition, and other required conditions are safe.

A is incorrect: At one universal pressure that applies to every Type III refrigerant invents a universal or premature transition. The manufacturer-approved conditions control the switch to liquid charging.
B is incorrect: Immediately after the first ounce of vapor enters invents a universal or premature transition. The manufacturer-approved conditions control the switch to liquid charging.
C is incorrect: Only after the chiller is running at full load does not satisfy the governing Vapor-to-liquid charging transition principle for this scenario. The correct condition is: When the manufacturer-approved procedure indicates the required pressure, temperature, water, and system conditions are safe.

Topic: Vapor-to-liquid charging transition
Suggested error code: CHG
Review: 9.8 - Recharging Low-Pressure Systems

Question 15

Correct answer: A. The manufacture or import date of the recovery/recycling equipment

The November 15, 1993 date refers to the manufacture/import date of the recovery/recycling equipment. The normal low-pressure endpoint remains 25 mm Hg absolute in both date columns.

B is incorrect: The date the chiller was manufactured gives a different low-pressure endpoint, but the current low-pressure row is 25 mm Hg absolute in both date columns.
C is incorrect: The date the refrigerant was produced gives a different low-pressure endpoint, but the current low-pressure row is 25 mm Hg absolute in both date columns.
D is incorrect: The date the building received its certificate of occupancy gives a different low-pressure endpoint, but the current low-pressure row is 25 mm Hg absolute in both date columns.

Topic: Recovery-equipment date and Type III endpoint
Suggested error code: EVA
Review: 9.9 - Type III Evacuation Requirements

Current source: 40 CFR § 82.156 - Proper Evacuation of Refrigerant From Appliances; EPA - Required Level of Evacuation of Appliances

Question 16

Correct answer: B. It is an absolute pressure close to 0.98 in. Hg absolute, not a 25-in. vacuum reading

The Type III value is 25 mm Hg absolute, an absolute pressure near 0.98 in. Hg absolute. It is not a 25-in. Hg vacuum reading or a positive gauge pressure.

A is incorrect: It is the same as 25 in. Hg vacuum confuses inches of mercury vacuum with the current low-pressure requirement of 25 mm Hg absolute.
C is incorrect: It is the same as 25 psig is positive gauge pressure and is not the required low-pressure evacuation condition.
D is incorrect: It is the traditional recovery-vessel rupture-disc pressure does not satisfy the governing Meaning of 25 mm Hg absolute principle for this scenario. The correct condition is: It is an absolute pressure close to 0.98 in. Hg absolute, not a 25-in. vacuum reading.

Topic: Meaning of 25 mm Hg absolute
Suggested error code: UNIT
Review: 9.9 - Type III Evacuation Requirements

Current source: 40 CFR § 82.156 - Proper Evacuation of Refrigerant From Appliances; EPA - Required Level of Evacuation of Appliances

Question 17

Correct answer: C. 25 mm Hg absolute

For a normal non-leaking low-pressure appliance prepared for disposal, the current Table 1 evacuation endpoint is 25 mm Hg absolute.

A is incorrect: 0 psig is used only in specific low-pressure exceptions; it is not the normal Table 1 endpoint.
B is incorrect: 5 psig belongs to the current oil-change provision, not this Type III condition.
D is incorrect: 10 in. Hg vacuum is associated with other pressure-category evacuation conditions, not the normal Type III low-pressure Table 1 endpoint.

Topic: Low-pressure evacuation before disposal
Suggested error code: EVA
Review: 9.9 - Type III Evacuation Requirements

Current source: 40 CFR § 82.156 - Proper Evacuation of Refrigerant From Appliances; EPA - Required Level of Evacuation of Appliances

Question 18

Correct answer: D. The work must be non-major and evacuation of the appliance to the atmosphere is not to be performed after completion of the work

The special low-pressure non-major provision applies only when the work is not major and the regulation’s additional conditions are met, including that evacuation to atmosphere is not to be performed after the work is completed.

A is incorrect: The work must be major and the compressor must be removed does not satisfy the governing Conditions for qualifying non-major opening principle for this scenario. The correct condition is: The work must be non-major and evacuation of the appliance to the atmosphere is not to be performed after completion of the work.
B is incorrect: The refrigerant charge must exceed 200 lb does not satisfy the governing Conditions for qualifying non-major opening principle for this scenario. The correct condition is: The work must be non-major and evacuation of the appliance to the atmosphere is not to be performed after completion of the work.
C is incorrect: The appliance must use recovery equipment manufactured before 1993 does not satisfy the governing Conditions for qualifying non-major opening principle for this scenario. The correct condition is: The work must be non-major and evacuation of the appliance to the atmosphere is not to be performed after completion of the work.

Topic: Conditions for qualifying non-major opening
Suggested error code: REG
Review: 9.9 - Type III Evacuation Requirements

Current source: 40 CFR § 82.156 - Proper Evacuation of Refrigerant From Appliances; 40 CFR § 82.152 - Definitions

Question 19

Correct answer: A. The rise can result from moisture/outgassing or leakage and must be diagnosed; the pressure pattern alone is not absolute proof of one cause

During post-service vacuum evaluation, pressure rise can result from moisture/outgassing or leakage. The pressure trend is diagnostic evidence and must be evaluated; it does not prove one cause by itself.

B is incorrect: Any rise proves only an external leak is too absolute. Pressure rise can have more than one cause and must be interpreted in the context of recovery or post-service vacuum diagnosis.
C is incorrect: Any rise proves only liquid refrigerant remains is too absolute. Pressure rise can have more than one cause and must be interpreted in the context of recovery or post-service vacuum diagnosis.
D is incorrect: A rise means the system has reached perfect vacuum does not satisfy the governing Standing-vacuum pressure-rise diagnosis principle for this scenario. The correct condition is: The rise can result from moisture/outgassing or leakage and must be diagnosed; the pressure pattern alone is not absolute proof of one cause.

Topic: Standing-vacuum pressure-rise diagnosis
Suggested error code: VAC
Review: 9.9 - Type III Evacuation Requirements

Question 20

Correct answer: B. Do not use simple series relief valves as redundant protection; approved engineered relief arrangements are different

A is incorrect: This is preferred because the second valve always doubles flow capacity is too absolute for the condition in this question. The correct answer depends on the specific Type III pressure, equipment, or service condition.
C is incorrect: Cap the downstream valve so the upstream valve sees more pressure does not satisfy the governing Pressure-relief arrangement principle for this scenario. The correct condition is: Do not use simple series relief valves as redundant protection; approved engineered relief arrangements are different.
D is incorrect: Replace both valves with the evaporator charging valve does not satisfy the governing Pressure-relief arrangement principle for this scenario. The correct condition is: Do not use simple series relief valves as redundant protection; approved engineered relief arrangements are different.

Topic: Pressure-relief arrangement
Suggested error code: SAF
Review: 9.10 - Type III Safety and Machinery Rooms

Question 21

Correct answer: C. The refrigerant alarm indicates target refrigerant in room air, and 19.4% O₂ is oxygen deficient because the OSHA threshold is below 19.5% O₂

A is incorrect: The refrigerant detector is measuring oxygen, so the 19.4% reading can be ignored reverses the instrument functions. The refrigerant detector measures target refrigerant, not oxygen concentration.
B is incorrect: The oxygen monitor is measuring refrigerant concentration, so no oxygen hazard can exist reverses the instrument functions. The oxygen monitor measures oxygen concentration, not refrigerant concentration.
D is incorrect: A pressure gauge should be used instead because it measures both refrigerant concentration and oxygen confuses system pressure with room-air composition. A pressure gauge does not replace refrigerant or oxygen monitoring.

Topic: Refrigerant detection and oxygen deficiency
Suggested error code: SAF
Review: 9.10 - Type III Safety and Machinery Rooms

Safety source: OSHA 29 CFR 1910.146 - Permit-Required Confined Spaces

Question 22

Correct answer: D. The actual space must meet the confined-space criteria; a machinery room is not automatically a confined space

A refrigeration machinery room is not automatically an OSHA confined space. The actual space must meet the regulatory criteria; separate pits, vessels, or water boxes may require their own evaluation.

A is incorrect: Every machinery room is automatically a permit-required confined space overgeneralizes the OSHA definition. The actual space must satisfy the confined-space criteria.
B is incorrect: A machinery room is never hazardous because it is designed for equipment confuses “not automatically a confined space” with “safe.” A machinery room can still contain serious atmospheric and mechanical hazards.
C is incorrect: Any room containing a chiller is automatically oxygen deficient overgeneralizes the OSHA definition. The actual space must satisfy the confined-space criteria.

Topic: Machinery room versus confined space
Suggested error code: SAF
Review: 9.10 - Type III Safety and Machinery Rooms

Safety source: OSHA 29 CFR 1910.146 - Permit-Required Confined Spaces

Question 23

Correct answer: A. Replace the disc as required and investigate and correct the cause of the overpressure event

A ruptured disc does not reseal. Before returning the chiller to service, replace it as required and investigate/correct the cause of the abnormal overpressure event.

B is incorrect: Cap the relief outlet and restart immediately would defeat emergency pressure-relief protection and is unsafe.
C is incorrect: Install a higher-pressure disc without checking the design does not satisfy the governing Response after rupture-disc operation principle for this scenario. The correct condition is: Replace the disc as required and investigate and correct the cause of the overpressure event.
D is incorrect: Leave the ruptured disc in place because it will reseal when pressure falls does not satisfy the governing Response after rupture-disc operation principle for this scenario. The correct condition is: Replace the disc as required and investigate and correct the cause of the overpressure event.

Topic: Response after rupture-disc operation
Suggested error code: SAF
Review: 9.10 - Type III Safety and Machinery Rooms

Question 24

Correct answer: B. The cover can be heavy and may require rated lifting and support equipment

After the water side is safely isolated, depressurized, and drained, a large water-box cover can still be very heavy and may require rated lifting, rigging, and support equipment.

A is incorrect: The cover will become weightless when the water is drained is false; large water-box covers can remain very heavy and may require rated lifting and support equipment.
C is incorrect: The recovery-machine cutout must be raised to 15 psig does not satisfy the governing Water-box cover lifting hazard principle for this scenario. The correct condition is: The cover can be heavy and may require rated lifting and support equipment.
D is incorrect: The refrigerant monitor must be used as a lifting indicator does not satisfy the governing Water-box cover lifting hazard principle for this scenario. The correct condition is: The cover can be heavy and may require rated lifting and support equipment.

Topic: Water-box cover lifting hazard
Suggested error code: WTR
Review: 9.10 - Type III Safety and Machinery Rooms

Safety source: OSHA 29 CFR 1910.147 - The Control of Hazardous Energy

Question 25

Correct answer: C. The leaking portion is taken to the lowest attainable level without substantial contamination, and that level may not exceed 0 psig

A is incorrect: The leak allows the component to remain above atmospheric pressure does not satisfy the governing Leaking-appliance evacuation exception principle for this scenario. The correct condition is: The leaking portion is taken to the lowest attainable level without substantial contamination, and that level may not exceed 0 psig.
B is incorrect: The technician may stop recovery at 5 psig belongs to the current oil-change provision, not this Type III condition.
D is incorrect: The entire appliance is exempt from recovery once any leak is found incorrectly treats the existence of a leak as an exemption from recovery. A good-faith recovery effort and the lowest-attainable-level rule still apply.

Topic: Leaking-appliance evacuation exception
Suggested error code: REG
Review: 9.9 - Type III Evacuation Requirements

Current source: 40 CFR § 82.156 - Proper Evacuation of Refrigerant From Appliances; 40 CFR § 82.152 - Definitions

References

Current Regulatory and EPA Sources

U.S. Environmental Protection Agency, Section 608 Test Topics, current Type III topic framework, verified August 13, 2026.
U.S. Environmental Protection Agency, Stationary Refrigeration Service Practice Requirements, current recovery, opening, and service-practice framework, verified August 13, 2026.
U.S. Environmental Protection Agency, Required Level of Evacuation of Appliances, current low-pressure Table 1 requirement, verified August 13, 2026.
Electronic Code of Federal Regulations, 40 CFR § 82.152 - Definitions, low-pressure appliance and major-repair definitions, verified August 13, 2026.
Electronic Code of Federal Regulations, 40 CFR § 82.156 - Proper Evacuation of Refrigerant From Appliances, current evacuation table, non-major opening provision, leaking-appliance exception, and oil-change provision, verified August 13, 2026.
Electronic Code of Federal Regulations, 40 CFR § 82.161 - Technician Certification, current Type III certification scope, verified August 13, 2026.

Current Safety Sources

Occupational Safety and Health Administration, 29 CFR 1910.146 - Permit-Required Confined Spaces, confined-space criteria and oxygen-deficiency threshold, verified August 13, 2026.
Occupational Safety and Health Administration, 29 CFR 1910.147 - The Control of Hazardous Energy, hazardous-energy control principles used for applicable water-side service, verified August 13, 2026.
ASHRAE, Read-Only Versions of ASHRAE Standards, current published Standard 15-2024 and Standard 34-2024 status used in the Section 9.10 code review, verified August 13, 2026.

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EPA Section 608 Teaching Material and Universal Certification Preparation