EPA 608 609 Type III 3 — Questions and Answers
Question 1: When recovering refrigerant from a low-pressure appliance for major repair, the required recovery level depends on:
- Whether recovery/recycling equipment was made before or after Nov 15, 1993 (Correct answer)
- The size of the building
- The technician's experience level
- The ambient humidity
Correct answer: Whether recovery/recycling equipment was made before or after Nov 15, 1993
Required recovery vacuum levels differ for equipment manufactured before versus after November 15, 1993.
Question 2: Recovery equipment manufactured after November 15, 1993, must evacuate a low-pressure appliance to:
- 25 mm Hg absolute (Correct answer)
- 29 inches of vacuum
- 0 psig
- 15 inches of vacuum
Correct answer: 25 mm Hg absolute
Post-1993 recovery equipment must achieve 25 mm Hg absolute on low-pressure appliances.
Question 3: A potentially dangerous condition when adding nitrogen to pressurize a low-pressure system for leak testing is exceeding:
- 10 psig (Correct answer)
- 150 psig
- 50 psig
- 500 psig
Correct answer: 10 psig
Low-pressure appliances should not be pressurized above 10 psig, as higher pressures can cause a violent rupture.
Question 4: To raise system pressure for leak detection in a low-pressure chiller, a technician may safely use:
- Nitrogen with a trace of refrigerant, kept below 10 psig (Correct answer)
- Pure oxygen at 50 psig
- Compressed air at 100 psig
- Acetylene
Correct answer: Nitrogen with a trace of refrigerant, kept below 10 psig
A trace of refrigerant in nitrogen below 10 psig is used to detect leaks safely.
Question 5: Why should oxygen never be used to pressurize a refrigeration system for leak testing?
- It can react explosively with compressor oil (Correct answer)
- It is too expensive
- It dissolves the refrigerant
- It freezes the lines
Correct answer: It can react explosively with compressor oil
Oxygen can combine with oil and cause a violent explosion.
Question 6: When pressurizing a low-pressure appliance for leak testing, the safest gas to use is:
- Controlled amounts of nitrogen (Correct answer)
- Compressed shop air
- Pure oxygen
- Carbon monoxide
Correct answer: Controlled amounts of nitrogen
Nitrogen is an inert gas safe for pressurizing systems.
Question 7: Heating the refrigerant in a low-pressure appliance during recovery is used to:
- Speed up recovery by raising vapor pressure (Correct answer)
- Damage the compressor
- Reduce the charge weight
- Convert it to a high-pressure refrigerant
Correct answer: Speed up recovery by raising vapor pressure
Gently warming the refrigerant raises its pressure, allowing faster and more complete recovery.
EPA 608 609 Type III 3
When recovering refrigerant from a low-pressure appliance for major repair, the required recovery level depends on: