9.7 - Refrigerant in Oil
Module: Type III Low-Pressure Appliances
Technical and regulatory verification date: August 13, 2026
Primary current authority: Current EPA Section 608 Type III test topics and 40 CFR § 82.156 service-practice requirements
Course role: Explains why refrigerant remains dissolved in chiller oil after bulk liquid and vapor recovery, why the oil is heated during Type III recovery, how the 130°F examination value should be interpreted, how oil is removed safely, and how refrigerant released from the oil affects recovery completion
Learning Objectives
After completing this section, a student should be able to:
- Explain how refrigerant can remain dissolved in compressor oil after bulk liquid and vapor have been removed from a low-pressure chiller.
- Explain why dissolved refrigerant can cause a pressure rise or additional vapor generation during the later stages of recovery.
- Explain why heating the oil helps remove refrigerant from the oil.
- State the current EPA Type III examination topic that oil should be heated to 130°F before removal to minimize refrigerant release.
- Distinguish the 130°F Type III examination value from an unlimited permission to heat every chiller oil system to that temperature regardless of manufacturer instructions.
- Explain why oil temperature should be raised using the equipment’s approved heater or manufacturer-approved method rather than uncontrolled external heating.
- Explain how sudden pressure reduction can cause refrigerant dissolved in oil to boil out rapidly and produce oil foaming.
- State the current Section 608 oil-change pressure requirement of no higher than 5 psig before the appliance or isolated portion is opened, or the alternative system-receiver procedure permitted by § 82.156.
- Explain why removing oil does not automatically mean refrigerant recovery is complete.
- Describe the relationship among oil heating, vapor recovery, pressure rebound, and the final required recovery endpoint.
- Explain why conventional oil-system guidance does not apply identically to every modern centrifugal chiller, including oil-free designs.
- Distinguish Type III examination knowledge from manufacturer-specific oil-system temperature, heater, drainage, and handling limits.
Introduction
A low-pressure chiller can still contain refrigerant after the obvious liquid and vapor have been removed.
One important place where refrigerant can remain is:
COMPRESSOR OIL
Refrigerant and oil can form a solution. The amount of refrigerant dissolved in the oil depends on several factors, including:
- Refrigerant identity.
- Lubricant type.
- Temperature.
- Pressure.
- Previous operating condition.
- Time allowed for the refrigerant and oil to approach equilibrium.
This creates an important Type III recovery problem.
A technician may remove:
bulk liquid refrigerant
and then:
most free refrigerant vapor
while refrigerant still remains dissolved in the oil.
As recovery continues and pressure decreases, some of that dissolved refrigerant can leave the oil and become vapor.
The basic relationship is:
REFRIGERANT DISSOLVED IN OIL
↓
oil is warmed and/or pressure is reduced
↓
refrigerant leaves solution
↓
additional refrigerant vapor forms
↓
recovery must continue
EPA’s current Type III test-topic list specifically requires technicians to know the need to:
HEAT OIL TO 130°F
BEFORE REMOVING IT
TO MINIMIZE REFRIGERANT RELEASE
This is a major Type III exam-preparation value.
However, students must understand why the temperature matters and how it fits into the larger service procedure.
The correct lesson is not:
Heat every chiller oil system to 130°F
under all conditions.
The correct lesson is:
130°F
→ important EPA Type III examination value
→ heating reduces refrigerant retained in the oil before oil removal
FIELD SERVICE
→ follow the chiller manufacturer's approved oil-heating,
temperature, pressure, and oil-removal procedure
Key Concepts
1. Refrigerant Can Dissolve in Oil
Refrigerant and lubricating oil are not always completely separate fluids.
Depending on the refrigerant-oil combination, a portion of the refrigerant can dissolve into the lubricant.
Conceptually:
OIL
+
REFRIGERANT
→
REFRIGERANT-OIL SOLUTION
The dissolved refrigerant does not behave exactly like a separate pool of liquid refrigerant.
It can remain within the oil while the technician is recovering refrigerant vapor from the main chiller volume.
This is why:
NO VISIBLE LIQUID REFRIGERANT
≠
NO REFRIGERANT IN THE OIL
2. Why This Matters in Low-Pressure Chillers
Traditional centrifugal chillers can contain a substantial oil reservoir or sump.
The oil lubricates components such as:
- Bearings.
- Gears where applicable.
- Other compressor moving surfaces.
During operation, the oil is exposed to refrigerant.
Over time, refrigerant can dissolve in the oil.
When the chiller is taken out of service for refrigerant recovery:
bulk refrigerant is removed
but:
refrigerant dissolved in oil
can remain
This dissolved refrigerant becomes important near the end of recovery because it can continue to leave the oil and enter the refrigerant vapor space.
Why Refrigerant Leaves the Oil
1. Temperature Effect
For the Type III recovery condition taught in this course, warming the oil helps drive refrigerant out of the oil.
The teaching relationship is:
OIL TEMPERATURE ↑
→
LESS REFRIGERANT REMAINS DISSOLVED
→
MORE REFRIGERANT ENTERS VAPOR SPACE
→
RECOVERY MACHINE CAN REMOVE IT
This is why oil heating is part of the Type III recovery sequence.
2. Pressure Effect
Reducing system pressure also encourages dissolved refrigerant to leave the oil.
Conceptually:
SYSTEM PRESSURE ↓
→
refrigerant becomes less stable in solution
→
refrigerant vaporizes from oil
This explains why a chiller pressure can rise again after the recovery machine is temporarily isolated.
Additional refrigerant may be leaving:
- Residual liquid.
- Oil.
- Internal surfaces.
- Trapped regions.
Therefore:
PRESSURE REBOUND
does not automatically mean:
EXTERNAL AIR LEAK
It may indicate that refrigerant is still being released inside the appliance.
The detailed interpretation of pressure rise after the required Type III endpoint is covered in Section 9.9.
3. Temperature and Pressure Work Together
During late recovery, two processes can occur at the same time:
PRESSURE IS LOW
+
OIL IS WARMED
↓
dissolved refrigerant leaves oil
↓
refrigerant vapor becomes available for recovery
This is intentional when performed according to the approved procedure.
The goal is to remove refrigerant from the oil before the oil is drained or removed, rather than allowing that refrigerant to escape during oil handling.
The 130°F Type III Examination Value
1. Current EPA Test Topic
EPA’s current Type III test-topic list explicitly includes:
Need to heat oil to 130°F before removing it
to minimize refrigerant release
For the Section 608 Type III examination, remember:
OIL REMOVAL
→
HEAT OIL TO 130°F
→
MINIMIZE REFRIGERANT RELEASE
The 130°F value appears in EPA’s current Type III test topics.
2. Why 130°F Is Taught
Heating the oil reduces the amount of refrigerant retained in solution.
The refrigerant driven from the oil enters the refrigerant vapor space where it can be captured by the recovery process.
Thus:
HEAT OIL
↓
REFRIGERANT LEAVES OIL
↓
RECOVER THE RELEASED VAPOR
↓
LESS REFRIGERANT REMAINS IN OIL
WHEN OIL IS REMOVED
The environmental purpose is to reduce refrigerant release during oil removal.
3. 130°F Is Not a Universal Permission to Overheat the Oil System
The exam value must not be interpreted as permission to ignore:
- Chiller manufacturer limits.
- Oil-heater controls.
- Oil type.
- Bearing or seal limitations.
- Heater wattage.
- Oil-system construction.
- Refrigerant compatibility.
- Temperature-sensor limits.
- Safety interlocks.
- Required shutdown procedures.
Field service must use the approved oil-heating procedure for the actual equipment.
If the manufacturer establishes a lower allowable temperature or a specific oil-removal procedure, do not override that procedure merely to reproduce a memorized exam number.
Exam Versus Field Distinction
EPA TYPE III EXAM KNOWLEDGE
→ 130°F before oil removal
FIELD PROCEDURE
→ manufacturer-approved oil-heating and oil-removal limits control
Heating the Oil Safely
1. Use the Approved Oil Heater When Available
Many conventional centrifugal chillers include an oil heater.
Depending on design, the heater can help:
- Maintain oil temperature.
- Reduce refrigerant accumulation in oil.
- Promote refrigerant release from oil during shutdown/recovery.
- Prepare the oil for approved service procedures.
The exact heater arrangement varies by chiller.
Possible designs can include:
- Immersion-type heater.
- External reservoir heater.
- Heater integrated into the oil sump.
- Manufacturer-specific temperature-control system.
Do not assume every chiller uses the same heater.
2. Do Not Use Open Flame
Do not use:
- Torch.
- Open flame.
- Uncontrolled heating device.
- Improvised heater that can overheat the oil or equipment.
The correct relationship is:
CONTROLLED APPROVED HEAT
→ acceptable
not:
MORE HEAT
→ faster and therefore better
Uncontrolled heating can damage:
- Oil.
- Seals.
- Wiring.
- Heater elements.
- Temperature sensors.
- Compressor components.
It can also create unsafe conditions.
3. Monitor Oil Temperature
Oil temperature should be measured using the equipment’s:
- Installed temperature sensor.
- Approved service instrumentation.
- Manufacturer-specified measurement location.
A temperature measured at the outer surface of an oil reservoir may not always represent the actual oil temperature throughout the reservoir.
Follow the manufacturer procedure.
4. Allow Time for Refrigerant to Leave the Oil
Heating the oil is not useful if the technician immediately drains it before the released refrigerant has been recovered.
The conceptual sequence is:
HEAT OIL
↓
ALLOW REFRIGERANT TO LEAVE SOLUTION
↓
RECOVER THE RESULTING VAPOR
↓
VERIFY RECOVERY CONDITION
↓
REMOVE OIL AS REQUIRED
The project does not assign one universal heating time because oil volume, heater capacity, refrigerant, chiller design, and manufacturer procedures vary.
Oil Foaming
1. What Is Oil Foaming?
Oil can contain dissolved refrigerant.
If pressure over the oil drops rapidly:
DISSOLVED REFRIGERANT
→ rapidly boils out of oil
→ bubbles form
→ oil can foam
Foaming is therefore the rapid formation of refrigerant vapor bubbles in oil.
2. Why Foaming Matters
Severe foaming can:
- Carry oil out of the oil reservoir.
- Move oil into refrigerant piping.
- Reduce the oil level available for lubrication.
- Complicate refrigerant recovery.
- Contaminate recovery equipment.
- Produce unstable oil-level readings.
This is one reason pressure reduction and oil heating should be controlled rather than abrupt.
3. Heating and Foaming Are Not Contradictory
Students may ask:
If heating causes refrigerant to leave the oil, why is heating recommended if refrigerant boiling out can cause foaming?
The answer is control.
The desired process is:
CONTROLLED HEATING
+
CONTROLLED PRESSURE
→
refrigerant leaves oil in a manageable way
→
recovery equipment captures it
The undesired process is:
SUDDEN PRESSURE DROP
or uncontrolled heating
→
rapid refrigerant boiling
→
severe oil foaming
Oil Removal and the Current Section 608 Pressure Rule
1. Oil Can Contain Significant Refrigerant
Current EPA service-practice guidance specifically recognizes that refrigeration oil can contain substantial dissolved refrigerant.
Therefore, oil removal is treated as a refrigerant-management operation.
The oil should not simply be drained from a pressurized refrigerant-containing appliance without satisfying the applicable service-practice requirement.
2. Current § 82.156 Oil-Change Rule
Source: 40 CFR § 82.156(a)(1)(iii)
For purposes of an oil change, the regulation permits either of the following approaches:
Approach A
The appliance or isolated portion must be:
EVACUATED OR PRESSURIZED
TO NO HIGHER THAN 5 psig
BEFORE IT IS OPENED
or:
Approach B
The oil may be:
DRAINED INTO A SYSTEM RECEIVER
that is then:
EVACUATED OR PRESSURIZED
TO NO HIGHER THAN 5 psig
This current federal pressure rule is separate from the Type III oil-temperature exam value.
3. Do Not Confuse 130°F With 5 psig
These numbers answer different questions.
| Value | What It Means |
|---|---|
| 130°F | Current EPA Type III exam topic for heating oil before removal to minimize refrigerant release |
| 5 psig maximum | Current § 82.156 pressure limit associated with the oil-change opening / system-receiver procedure |
Memory relationship:
OIL TEMPERATURE
→ 130°F
OIL-CHANGE PRESSURE
→ no higher than 5 psig
Do not interchange them.
4. The 5 psig Rule Is Not the Final Type III Recovery Endpoint
The 5 psig oil-change rule is a special service-practice provision for oil changes.
It is not:
- The normal Type III required evacuation endpoint.
- The recovery-unit high-pressure cutout.
- The low-pressure recovery-vessel rupture-disc setting.
- The low-pressure leak-test maximum.
Those other values belong to different procedures.
The current low-pressure appliance evacuation requirement is covered in Section 9.9.
Generalized Oil-Refrigerant Recovery Sequence
The exact procedure is manufacturer-specific, but the Type III reasoning sequence is:
Step 1 — Recover Bulk Refrigerant
Complete the normal Type III sequence developed in Section 9.5:
LIQUID FIRST
→
VAPOR SECOND
Step 2 — Recognize That Refrigerant Can Remain in Oil
Do not assume:
bulk liquid gone
+
low system pressure
=
oil contains no refrigerant
Refrigerant can remain dissolved in the oil.
Step 3 — Establish the Approved Oil-Heating Condition
Use the manufacturer’s approved heater and procedure.
For exam preparation:
130°F
is the key oil-heating value to remember.
Step 4 — Continue Recovery While Refrigerant Leaves the Oil
As refrigerant is released from the oil:
refrigerant vapor forms
→
recovery equipment removes it
This is the reason oil heating should be coordinated with active or available refrigerant recovery.
Step 5 — Observe System Pressure
After the required recovery condition is reached and the system is isolated as directed:
observe pressure
If pressure rises:
refrigerant may still be leaving oil
or another internal refrigerant source
→
additional recovery may be required
Do not immediately classify every pressure rise as an external leak.
Step 6 — Satisfy the Applicable Oil-Change Pressure Requirement
Before opening for oil removal, satisfy the current § 82.156 oil-change condition:
NO HIGHER THAN 5 psig
or use the permitted system-receiver procedure.
Step 7 — Remove Oil According to Manufacturer Procedure
Use the approved:
- Oil drain.
- Oil receiver.
- Container.
- Personal protective equipment.
- Temperature limit.
- Pressure condition.
- Valve sequence.
Avoid uncontrolled release of refrigerant or hot oil.
Step 8 — Continue to the Required Final Recovery Condition
Oil removal is not automatically the end of refrigerant recovery.
If the appliance is being opened for service or disposed of, the applicable current Section 608 recovery/evacuation requirement must still be satisfied unless a specific exception applies.
The exact Type III requirement is developed in Section 9.9.
Recovery Completion
1. Recovery Is Not Complete Merely Because the Oil Has Been Drained
The appliance can still contain refrigerant in:
- Vapor spaces.
- Residual liquid pockets.
- Internal piping.
- Purge components.
- Other connected sections.
Therefore:
OIL REMOVED
≠
RECOVERY COMPLETE
2. Recovery Is Not Complete Merely Because One Pressure Reading Is Reached
A low pressure reading can temporarily occur while:
- Oil still contains dissolved refrigerant.
- Residual liquid is still evaporating.
- Internal temperatures are still changing.
After the recovery machine is stopped or isolated, refrigerant released from the oil can cause:
PRESSURE REBOUND
This is why the pressure-rise check is important.
3. Completion Requires the Applicable Endpoint and Stable Evaluation
A generalized completion sequence is:
RECOVER BULK LIQUID
↓
RECOVER VAPOR
↓
HEAT OIL / RELEASE DISSOLVED REFRIGERANT
↓
RECOVER ADDITIONAL VAPOR
↓
REACH APPLICABLE REQUIRED ENDPOINT
↓
STOP / ISOLATE AS DIRECTED
↓
OBSERVE FOR PRESSURE RISE
↓
additional refrigerant indicated?
If yes:
RESUME RECOVERY AS REQUIRED
If no:
PROCEED ACCORDING TO
CURRENT REQUIREMENTS
AND MANUFACTURER PROCEDURE
Section 9.9 provides the exact Type III regulatory endpoint and interpretation.
Conventional Oil-Lubricated Versus Oil-Free Chillers
1. Traditional Type III Exam Model
The traditional Type III examination model assumes a low-pressure centrifugal chiller with a conventional oil system.
That model can include:
- Oil reservoir.
- Oil pump.
- Oil heater.
- Oil filter.
- Bearings.
- Refrigerant dissolved in oil.
The 130°F oil-heating exam point applies to this conventional oil-containing recovery context.
2. Some Modern Centrifugal Chillers Are Oil-Free
Some centrifugal chillers use technologies such as magnetic bearings and may not have a conventional compressor-oil circuit.
Therefore:
CENTRIFUGAL CHILLER
≠
ALWAYS HAS CONVENTIONAL OIL RESERVOIR
If the machine is oil-free, an oil-removal procedure obviously cannot be applied in the same way.
The technician must identify the actual equipment design before service.
3. Certification Questions Can Still Use Traditional Equipment
The existence of modern oil-free chillers does not eliminate the traditional oil-related Type III exam topics.
EPA’s current Type III topic list still includes the 130°F oil-heating requirement.
Therefore, students must know the classic conventional-chiller procedure even if they later work on equipment with a different lubrication design.
Oil Removal Safety
1. Hot Oil Can Burn
Oil heated for service can cause thermal burns.
Use appropriate:
- Gloves.
- Eye protection.
- Protective clothing.
- Drain equipment.
- Containers.
Do not assume oil is safe to touch because refrigerant pressure is low.
2. Refrigerant Can Flash From Removed Oil
Even after proper heating and recovery, removed oil may still contain some dissolved refrigerant.
As pressure changes:
remaining dissolved refrigerant
→
can vaporize
Handle oil in a way that prevents uncontrolled exposure and refrigerant release.
3. Do Not Seal Hot Refrigerant-Containing Oil in an Inappropriate Container
If refrigerant continues to leave the oil after drainage, pressure can build in a closed container.
Use only containers and procedures appropriate for the service operation and applicable waste-management requirements.
4. Do Not Mix Oil Handling With Refrigerant Venting
The purpose of heating the oil is:
REMOVE MORE REFRIGERANT THROUGH RECOVERY
BEFORE OIL IS REMOVED
not:
HEAT OIL SO REFRIGERANT VENTS FASTER
The released refrigerant should be captured through the recovery process.
Important Terms
Dissolved Refrigerant
Dissolved refrigerant is refrigerant held in solution within compressor oil or another lubricant rather than existing as a separate free liquid or vapor phase.
Desorption / Refrigerant Release From Oil
Desorption in this teaching context refers to refrigerant leaving the oil solution and entering the refrigerant vapor space as temperature and pressure conditions change.
Oil Foaming
Oil foaming is the formation of many refrigerant vapor bubbles in oil when dissolved refrigerant boils out rapidly, often after a sudden pressure reduction.
Oil Heater
An oil heater is an equipment heater used on applicable compressor-oil systems to maintain or raise oil temperature according to manufacturer requirements.
Oil Reservoir / Sump
The oil reservoir or oil sump stores lubricating oil used by a conventional compressor lubrication system.
Pressure Rebound
Pressure rebound is a rise in appliance pressure after recovery is stopped or the appliance is isolated. Refrigerant vaporizing from residual liquid or leaving oil can contribute to the rise.
Recovery Completion
Recovery completion means that the applicable refrigerant-removal requirement has been satisfied and remaining internal refrigerant sources have been properly evaluated according to current requirements and manufacturer procedures.
EPA 608 Exam Focus
What Students Must Remember
- Refrigerant can remain dissolved in oil after bulk liquid and vapor recovery.
- Oil heating helps refrigerant leave the oil so it can be recovered before the oil is removed.
- EPA’s current Type III test topics specifically require:
HEAT OIL TO 130°F
BEFORE REMOVING IT
TO MINIMIZE REFRIGERANT RELEASE
- The reason for heating is:
higher oil temperature
→ less refrigerant retained in oil
→ more refrigerant becomes available for recovery
- Do not drain the oil and assume the refrigerant contained in it is automatically recovered.
- Sudden pressure reduction can cause refrigerant to boil rapidly out of the oil and produce foaming.
- The current oil-change pressure requirement is:
NO HIGHER THAN 5 psig
before opening, or use the permitted system-receiver procedure.
130°Fand5 psigrefer to different conditions.5 psigis not the normal final Type III evacuation requirement.- A pressure rise after recovery can occur because refrigerant is still leaving the oil.
- Oil heating should use the approved equipment and manufacturer procedure.
- Do not use uncontrolled heat or open flame.
- Some modern centrifugal chillers are oil-free, but the traditional oil-related Type III exam questions remain valid examination content.
- Removing oil does not automatically complete refrigerant recovery.
- The exact Type III evacuation endpoint is covered in Section 9.9.
High-Priority Relationships
REFRIGERANT DISSOLVED IN OIL
→
HEAT OIL
→
REFRIGERANT LEAVES OIL
→
RECOVER VAPOR
TYPE III OIL EXAM VALUE
→
130°F
CURRENT OIL-CHANGE PRESSURE RULE
→
NO HIGHER THAN 5 psig
PRESSURE REBOUND
→
REFRIGERANT MAY STILL REMAIN
OIL REMOVED
≠
RECOVERY COMPLETE
Common Mistakes and Confusing Points
Mistake 1: Assuming All Refrigerant Is Gone After Liquid and Vapor Recovery
Refrigerant can still be dissolved in the oil.
Mistake 2: Forgetting the 130°F Type III Value
EPA currently lists heating oil to 130°F before removal as a Type III test topic.
Mistake 3: Treating 130°F as Permission to Ignore Manufacturer Limits
The exam value is important.
Actual equipment service still requires the approved manufacturer procedure and allowable oil-temperature range.
Mistake 4: Heating Oil With a Torch
Use approved controlled heating.
Never apply open flame as a substitute for the proper oil heater.
Mistake 5: Draining Oil Before Recovering Refrigerant Released From It
The purpose of heating is to allow refrigerant to leave the oil while it can still be captured.
Mistake 6: Confusing 130°F With 5 psig
Remember:
130°F
→ OIL TEMPERATURE
5 psig MAX
→ OIL-CHANGE PRESSURE CONDITION
Mistake 7: Treating 5 psig as the Type III Final Evacuation Level
It is not.
The final low-pressure evacuation requirement is taught in Section 9.9.
Mistake 8: Assuming Pressure Rebound Always Means an External Leak
Refrigerant leaving oil can raise pressure after the recovery machine is isolated.
Residual liquid and moisture can also affect pressure behavior.
Mistake 9: Ignoring Oil Foaming
Rapid pressure reduction can cause dissolved refrigerant to boil out rapidly and foam the oil.
Mistake 10: Assuming Every Centrifugal Chiller Has a Conventional Oil System
Some modern centrifugal chillers are oil-free.
Identify the actual machine design.
Mistake 11: Treating Oil Removal as the Last Required Recovery Step
The appliance must still satisfy the applicable refrigerant-removal requirement.
Mistake 12: Treating the EPA Test Topic as a Complete Manufacturer Service Manual
The certification exam gives the key principle and value.
The service manual controls the detailed heater operation, drain sequence, instrumentation, and equipment-specific limits.
Concept-Check Questions
Question 1
Why can refrigerant still remain in a low-pressure chiller after bulk liquid and most free vapor have been recovered?
A. Refrigerant can remain dissolved in the compressor oil.
B. Refrigerant permanently converts to water.
C. The condenser-water circuit creates new refrigerant.
D. Recovery equipment cannot remove any vapor from a chiller.
Question 2
According to EPA’s current Type III test topics, to what temperature should oil be heated before it is removed to minimize refrigerant release?
A. 85°F
B. 100°F
C. 130°F
D. 212°F
Question 3
Why is the oil heated before removal during Type III recovery?
A. To increase the amount of refrigerant retained permanently in the oil.
B. To help refrigerant leave the oil so it can be captured by the recovery process.
C. To raise the refrigerant’s ozone-depletion potential.
D. To convert compressor oil into refrigerant.
Question 4
Which statement correctly describes the current Section 608 oil-change pressure requirement?
A. The appliance must always be opened at exactly 10 psig.
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.
C. The appliance must always be opened under 15 psig.
D. No pressure requirement applies because refrigerant contained in oil is exempt.
Question 5
What can cause oil to foam during refrigerant recovery?
A. Rapid boiling of dissolved refrigerant out of the oil after a pressure reduction.
B. Condenser water changing into compressor oil.
C. A refrigerant monitor measuring room air.
D. The recovery vessel becoming completely empty.
Question 6
A technician reaches a low pressure, isolates the recovery machine, and then sees the chiller pressure rise. Which explanation should be considered?
A. Refrigerant may still be leaving the oil or vaporizing from another internal source.
B. The oil has become a noncondensable gas.
C. The chiller is necessarily completely refrigerant-free.
D. The pressure rise proves the recovery-machine condenser is full of water.
Question 7
Which statement best describes the relationship between the 130°F EPA Type III value and manufacturer instructions?
A. The 130°F value allows every oil system to be heated without regard to equipment limits.
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.
C. Manufacturer instructions can be ignored during certification-related service.
D. The 130°F value applies only to condenser-water temperature.
Question 8
Which statement best describes recovery completion after oil has been heated and removed?
A. Oil removal automatically proves that all refrigerant has been recovered.
B. The technician may vent any remaining vapor after the oil is removed.
C. The appliance must still satisfy the applicable recovery/evacuation requirement, and pressure rebound may show that additional refrigerant remains.
D. The final evacuation requirement no longer applies to Type III appliances.
Answers and detailed explanations will be provided in
9.15 - Answers and Explanations.md.
Section Summary
Refrigerant recovery from a low-pressure chiller is not complete simply because bulk liquid and most free vapor have been removed.
Refrigerant can remain:
DISSOLVED IN COMPRESSOR OIL
As oil temperature rises and system pressure falls:
refrigerant leaves the oil
→
additional vapor forms
→
recovery can continue
EPA’s current Type III examination topic requires technicians to remember:
HEAT OIL TO 130°F
BEFORE REMOVING IT
TO MINIMIZE REFRIGERANT RELEASE
The value is important for the exam, but actual field service must follow the manufacturer’s approved oil-temperature and oil-removal procedure.
The current Section 608 oil-change pressure rule is separate:
OIL CHANGE
→
NO HIGHER THAN 5 psig BEFORE OPENING
or use the permitted system-receiver procedure.
The most important distinctions are:
130°F
→ oil-heating exam value
5 psig
→ oil-change pressure condition
pressure rebound
→ refrigerant may still remain
oil removed
≠
recovery complete
The next section develops the Type III charging sequence, including the evaporator charging connection and the critical requirement to introduce vapor before liquid:
Section 9.8 - Recharging Low-Pressure Systems.
References
Current EPA and Regulatory Sources
-
U.S. Environmental Protection Agency, Section 608 Test Topics, Type III Recovery Techniques, current page verified August 13, 2026. The current EPA topic list includes the requirement to heat oil to 130°F before removing it to minimize refrigerant release.
-
U.S. Environmental Protection Agency, Stationary Refrigeration Service Practice Requirements, “Changing Refrigerant Oil,” current page verified August 13, 2026. EPA explains that oil can contain large amounts of dissolved refrigerant and summarizes the current oil-change pressure requirements.
-
Electronic Code of Federal Regulations, 40 CFR § 82.156 - Proper Evacuation of Refrigerant From Appliances, § 82.156(a)(1)(iii), current regulation verified August 13, 2026.
Project Teaching and Technical Sources
-
International Training Institute for the Sheet Metal and Air Conditioning Industry, EPA Section 608 Study Guide, Type III Recovery Techniques. The project copy states that a temperature of 130°F should be attained when removing oil from a low-pressure system and explains that less refrigerant is contained in the oil at the higher temperature.
-
Rex Miller and Mark R. Miller, HVAC Licensing Study Guide, 3rd ed., refrigeration-oil and refrigerant solution/foaming principles. The glossary defines foaming as refrigerant rapidly boiling out of oil after a pressure reduction.