EPA Section 608 Type III Certification Practice Exam Study Guide Updated
2026 | Verified Questions and Answers with Detailed Rationales | Low-
Pressure Refrigeration Systems (Chillers), Recovery and Recycling
Procedures, Leak Detection and Repair Requirements, EPA Regulations
and Clean Air Act Compliance, Refrigerant Properties and Safety, System
Evacuation and Charging, Vacuum and Pressure Control, Recovery
Equipment Operation, Environmental Impact and Ozone Protection, HVAC
Service and Troubleshooting | Complete Exam Prep Resource for EPA
608 Type III Certification Success
Question 1: Which of the following refrigerants is classified as a low-pressure
refrigerant under EPA 608 Type III certification?
A. R-134a
B. R-410A
C. R-123
D. R-32
CORRECT ANSWER: C. R-123
Rationale: R-123 is a hydrochlorofluorocarbon (HCFC) refrigerant specifically classified
as a low-pressure refrigerant used primarily in centrifugal chillers. EPA 608 Type III
certification covers servicing of low-pressure appliances containing refrigerants such as
R-11, R-123, R-1233zd, and R-245fa. R-134a, R-410A, and R-32 are high-pressure
refrigerants covered under Type II certification.
Question 2: What is the EPA-mandated evacuation level for recovery or recycling
equipment used on low-pressure appliances?
A. 0 inches of Hg vacuum
B. 4 inches of Hg vacuum
C. 10 inches of Hg vacuum
D. 25 mm Hg absolute
CORRECT ANSWER: D. 25 mm Hg absolute
Rationale: EPA regulations require that low-pressure appliances be evacuated to 25 mm
Hg absolute regardless of whether the recovery equipment was manufactured before or
after November 15, 1993. This stringent vacuum level ensures maximum refrigerant
recovery from systems that operate below atmospheric pressure.
Question 3: When performing leak testing on a low-pressure centrifugal chiller,
which pressurization method is preferred by EPA guidelines?
A. Nitrogen pressurization to 10 psig
B. Compressed air pressurization to 5 psig
C. Hot-water method or built-in system heating equipment
D. Refrigerant vapor pressurization to atmospheric pressure
,CORRECT ANSWER: C. Hot-water method or built-in system heating equipment
Rationale: The hot-water method or using the chiller's built-in heating equipment is the
preferred method for pressurizing low-pressure systems for leak testing because it
avoids introducing non-condensable gases or moisture. Nitrogen or compressed air can
contaminate the system and require additional purging, while refrigerant vapor
pressurization is less controlled and may not provide adequate pressure for effective
leak detection.
Question 4: What is the maximum allowable annual leak rate for a comfort cooling
appliance containing more than 50 pounds of ozone-depleting refrigerant?
A. 5%
B. 10%
C. 20%
D. 30%
CORRECT ANSWER: B. 10%
Rationale: EPA leak repair regulations under Section 608 establish trigger leak rates
based on appliance type. For comfort cooling appliances (including chillers used for air
conditioning), the allowable annual leak rate is 10% of the full charge. Exceeding this
threshold requires corrective action within 30 days or development of a
retrofit/retirement plan.
Question 5: Before removing oil from a low-pressure refrigeration system, to what
minimum temperature should the oil be heated to minimize refrigerant release?
A. 100°F
B. 115°F
C. 130°F
D. 150°F
CORRECT ANSWER: C. 130°F
Rationale: Heating oil to at least 130°F before removal reduces the amount of dissolved
refrigerant in the oil, minimizing refrigerant emissions during the oil change procedure.
This practice is required by EPA regulations to maximize refrigerant recovery and protect
the environment.
Question 6: Why must water be circulated or removed from a chiller during
refrigerant evacuation?
A. To prevent corrosion of copper tubes
B. To prevent freezing of water in the tubes due to low pressure
C. To improve vacuum pump efficiency
D. To reduce evacuation time
CORRECT ANSWER: B. To prevent freezing of water in the tubes due to low pressure
,Rationale: During evacuation of low-pressure systems, the pressure drop can cause
water in the chiller tubes to freeze if not circulated or removed. Frozen water can
damage tubes and impede proper evacuation. Circulating water or draining the chiller
prevents this hazard and ensures effective refrigerant recovery.
Question 7: When recharging a centrifugal chiller, why should refrigerant vapor be
introduced before refrigerant liquid?
A. Vapor charges faster than liquid
B. Vapor prevents oil foaming in the compressor
C. Liquid introduction first can cause freezing of water in the evaporator tubes
D. Vapor is easier to meter accurately
CORRECT ANSWER: C. Liquid introduction first can cause freezing of water in the
evaporator tubes
Rationale: Introducing liquid refrigerant directly into a low-pressure evaporator can
cause rapid boiling and extreme cooling, potentially freezing water in the tubes and
causing mechanical damage. Vapor charging allows controlled pressure and
temperature increase, preventing freeze damage while safely restoring system charge.
Question 8: What is the primary purpose of a purge unit on a low-pressure
refrigeration system?
A. To recover refrigerant during system shutdown
B. To remove non-condensable gases from the condenser
C. To pressurize the system for leak testing
D. To filter moisture from the refrigerant
CORRECT ANSWER: B. To remove non-condensable gases from the condenser
Rationale: Low-pressure systems operate below atmospheric pressure, making them
susceptible to air and moisture infiltration. Purge units automatically remove non-
condensable gases (primarily air) that accumulate in the condenser, maintaining
system efficiency and preventing corrosion. Excessive purging can indicate system
leaks.
Question 9: According to ASHRAE Standard 15, what safety device is required in
equipment rooms containing low-pressure refrigeration systems?
A. High-pressure cutout switch
B. Oxygen deprivation sensor
C. Refrigerant leak detector for all refrigerants
D. Automatic fire suppression system
CORRECT ANSWER: B. Oxygen deprivation sensor
Rationale: ASHRAE Standard 15 requires an oxygen deprivation sensor in equipment
rooms housing refrigeration systems using any refrigerant, including low-pressure types.
, This sensor alerts personnel to dangerous oxygen levels that could result from
refrigerant leaks displacing breathable air, protecting worker safety.
Question 10: For low-pressure appliances containing R-123, ASHRAE Standard 15
additionally requires which specific safety device?
A. Carbon monoxide detector
B. Refrigerant sensor specific to R-123
C. Temperature monitoring alarm
D. Pressure relief valve with remote alarm
CORRECT ANSWER: B. Refrigerant sensor specific to R-123
Rationale: In addition to the general oxygen deprivation sensor requirement, ASHRAE
Standard 15 mandates a refrigerant-specific sensor for R-123 in equipment rooms. R-
123 has unique toxicity characteristics that warrant dedicated detection to provide early
warning of leaks before concentrations reach hazardous levels.
Question 11: When changing refrigerant oil in a low-pressure system, EPA
regulations require the system to be evacuated or pressurized to what maximum
pressure before oil removal?
A. 0 psig
B. 5 psig
C. 10 psig
D. Atmospheric pressure
CORRECT ANSWER: B. 5 psig
Rationale: EPA regulations prohibit changing oil at pressures higher than 5 psig to
ensure that dissolved refrigerant in the oil is recovered before oil removal. This
requirement minimizes refrigerant emissions during maintenance and protects
technician safety by reducing the risk of sudden refrigerant release.
Question 12: Which statement accurately describes the recovery process for low-
pressure refrigerants?
A. Recover vapor first to speed the process
B. Recover liquid first to speed the process
C. Recover oil before refrigerant to prevent contamination
D. Recover only vapor; liquid will evaporate naturally
CORRECT ANSWER: B. Recover liquid first to speed the process
Rationale: Recovering liquid refrigerant at the beginning of the recovery process
significantly speeds up overall recovery because liquid occupies much less volume
than vapor. After liquid recovery is complete, vapor recovery continues to achieve the
required evacuation level of 25 mm Hg absolute.
2026 | Verified Questions and Answers with Detailed Rationales | Low-
Pressure Refrigeration Systems (Chillers), Recovery and Recycling
Procedures, Leak Detection and Repair Requirements, EPA Regulations
and Clean Air Act Compliance, Refrigerant Properties and Safety, System
Evacuation and Charging, Vacuum and Pressure Control, Recovery
Equipment Operation, Environmental Impact and Ozone Protection, HVAC
Service and Troubleshooting | Complete Exam Prep Resource for EPA
608 Type III Certification Success
Question 1: Which of the following refrigerants is classified as a low-pressure
refrigerant under EPA 608 Type III certification?
A. R-134a
B. R-410A
C. R-123
D. R-32
CORRECT ANSWER: C. R-123
Rationale: R-123 is a hydrochlorofluorocarbon (HCFC) refrigerant specifically classified
as a low-pressure refrigerant used primarily in centrifugal chillers. EPA 608 Type III
certification covers servicing of low-pressure appliances containing refrigerants such as
R-11, R-123, R-1233zd, and R-245fa. R-134a, R-410A, and R-32 are high-pressure
refrigerants covered under Type II certification.
Question 2: What is the EPA-mandated evacuation level for recovery or recycling
equipment used on low-pressure appliances?
A. 0 inches of Hg vacuum
B. 4 inches of Hg vacuum
C. 10 inches of Hg vacuum
D. 25 mm Hg absolute
CORRECT ANSWER: D. 25 mm Hg absolute
Rationale: EPA regulations require that low-pressure appliances be evacuated to 25 mm
Hg absolute regardless of whether the recovery equipment was manufactured before or
after November 15, 1993. This stringent vacuum level ensures maximum refrigerant
recovery from systems that operate below atmospheric pressure.
Question 3: When performing leak testing on a low-pressure centrifugal chiller,
which pressurization method is preferred by EPA guidelines?
A. Nitrogen pressurization to 10 psig
B. Compressed air pressurization to 5 psig
C. Hot-water method or built-in system heating equipment
D. Refrigerant vapor pressurization to atmospheric pressure
,CORRECT ANSWER: C. Hot-water method or built-in system heating equipment
Rationale: The hot-water method or using the chiller's built-in heating equipment is the
preferred method for pressurizing low-pressure systems for leak testing because it
avoids introducing non-condensable gases or moisture. Nitrogen or compressed air can
contaminate the system and require additional purging, while refrigerant vapor
pressurization is less controlled and may not provide adequate pressure for effective
leak detection.
Question 4: What is the maximum allowable annual leak rate for a comfort cooling
appliance containing more than 50 pounds of ozone-depleting refrigerant?
A. 5%
B. 10%
C. 20%
D. 30%
CORRECT ANSWER: B. 10%
Rationale: EPA leak repair regulations under Section 608 establish trigger leak rates
based on appliance type. For comfort cooling appliances (including chillers used for air
conditioning), the allowable annual leak rate is 10% of the full charge. Exceeding this
threshold requires corrective action within 30 days or development of a
retrofit/retirement plan.
Question 5: Before removing oil from a low-pressure refrigeration system, to what
minimum temperature should the oil be heated to minimize refrigerant release?
A. 100°F
B. 115°F
C. 130°F
D. 150°F
CORRECT ANSWER: C. 130°F
Rationale: Heating oil to at least 130°F before removal reduces the amount of dissolved
refrigerant in the oil, minimizing refrigerant emissions during the oil change procedure.
This practice is required by EPA regulations to maximize refrigerant recovery and protect
the environment.
Question 6: Why must water be circulated or removed from a chiller during
refrigerant evacuation?
A. To prevent corrosion of copper tubes
B. To prevent freezing of water in the tubes due to low pressure
C. To improve vacuum pump efficiency
D. To reduce evacuation time
CORRECT ANSWER: B. To prevent freezing of water in the tubes due to low pressure
,Rationale: During evacuation of low-pressure systems, the pressure drop can cause
water in the chiller tubes to freeze if not circulated or removed. Frozen water can
damage tubes and impede proper evacuation. Circulating water or draining the chiller
prevents this hazard and ensures effective refrigerant recovery.
Question 7: When recharging a centrifugal chiller, why should refrigerant vapor be
introduced before refrigerant liquid?
A. Vapor charges faster than liquid
B. Vapor prevents oil foaming in the compressor
C. Liquid introduction first can cause freezing of water in the evaporator tubes
D. Vapor is easier to meter accurately
CORRECT ANSWER: C. Liquid introduction first can cause freezing of water in the
evaporator tubes
Rationale: Introducing liquid refrigerant directly into a low-pressure evaporator can
cause rapid boiling and extreme cooling, potentially freezing water in the tubes and
causing mechanical damage. Vapor charging allows controlled pressure and
temperature increase, preventing freeze damage while safely restoring system charge.
Question 8: What is the primary purpose of a purge unit on a low-pressure
refrigeration system?
A. To recover refrigerant during system shutdown
B. To remove non-condensable gases from the condenser
C. To pressurize the system for leak testing
D. To filter moisture from the refrigerant
CORRECT ANSWER: B. To remove non-condensable gases from the condenser
Rationale: Low-pressure systems operate below atmospheric pressure, making them
susceptible to air and moisture infiltration. Purge units automatically remove non-
condensable gases (primarily air) that accumulate in the condenser, maintaining
system efficiency and preventing corrosion. Excessive purging can indicate system
leaks.
Question 9: According to ASHRAE Standard 15, what safety device is required in
equipment rooms containing low-pressure refrigeration systems?
A. High-pressure cutout switch
B. Oxygen deprivation sensor
C. Refrigerant leak detector for all refrigerants
D. Automatic fire suppression system
CORRECT ANSWER: B. Oxygen deprivation sensor
Rationale: ASHRAE Standard 15 requires an oxygen deprivation sensor in equipment
rooms housing refrigeration systems using any refrigerant, including low-pressure types.
, This sensor alerts personnel to dangerous oxygen levels that could result from
refrigerant leaks displacing breathable air, protecting worker safety.
Question 10: For low-pressure appliances containing R-123, ASHRAE Standard 15
additionally requires which specific safety device?
A. Carbon monoxide detector
B. Refrigerant sensor specific to R-123
C. Temperature monitoring alarm
D. Pressure relief valve with remote alarm
CORRECT ANSWER: B. Refrigerant sensor specific to R-123
Rationale: In addition to the general oxygen deprivation sensor requirement, ASHRAE
Standard 15 mandates a refrigerant-specific sensor for R-123 in equipment rooms. R-
123 has unique toxicity characteristics that warrant dedicated detection to provide early
warning of leaks before concentrations reach hazardous levels.
Question 11: When changing refrigerant oil in a low-pressure system, EPA
regulations require the system to be evacuated or pressurized to what maximum
pressure before oil removal?
A. 0 psig
B. 5 psig
C. 10 psig
D. Atmospheric pressure
CORRECT ANSWER: B. 5 psig
Rationale: EPA regulations prohibit changing oil at pressures higher than 5 psig to
ensure that dissolved refrigerant in the oil is recovered before oil removal. This
requirement minimizes refrigerant emissions during maintenance and protects
technician safety by reducing the risk of sudden refrigerant release.
Question 12: Which statement accurately describes the recovery process for low-
pressure refrigerants?
A. Recover vapor first to speed the process
B. Recover liquid first to speed the process
C. Recover oil before refrigerant to prevent contamination
D. Recover only vapor; liquid will evaporate naturally
CORRECT ANSWER: B. Recover liquid first to speed the process
Rationale: Recovering liquid refrigerant at the beginning of the recovery process
significantly speeds up overall recovery because liquid occupies much less volume
than vapor. After liquid recovery is complete, vapor recovery continues to achieve the
required evacuation level of 25 mm Hg absolute.
