ASE Refrigerant Recovery, Recycling, and Handling 1 — Questions and Answers
Question 1: Which refrigerant has largely replaced R-134a in newer vehicle A/C systems due to its lower global warming potential?
- R-22
- R-1234yf (Correct answer)
- R-410A
- R-12
Correct answer: R-1234yf
R-1234yf (HFO-1234yf) replaced R-134a in many newer vehicles because it has a GWP of less than 1 compared to R-134a's GWP of 1,430.
Question 2: What federal regulation requires technicians to be certified before purchasing or handling refrigerants used in motor vehicle air conditioning?
- EPA Section 608
- EPA Section 609 (Correct answer)
- SAE J639
- CAA Title IV
Correct answer: EPA Section 609
EPA Section 609 of the Clean Air Act specifically covers technician certification and equipment standards for servicing motor vehicle air conditioning systems.
Question 3: Before opening a vehicle A/C system for service, the technician MUST first:
- Add UV dye to identify leaks
- Recover all refrigerant using approved equipment (Correct answer)
- Flush the system with nitrogen
- Measure the system superheat
Correct answer: Recover all refrigerant using approved equipment
EPA regulations prohibit venting refrigerants into the atmosphere; all refrigerant must be recovered with approved equipment before opening the system.
Question 4: A refrigerant identifier displays contamination in a sample recovered from a vehicle. The technician should:
- Recharge the system and note the contamination
- Mix it with clean refrigerant to dilute the contaminant
- Store it in a dedicated contaminated refrigerant cylinder and send it to a reclaimer (Correct answer)
- Vent it outdoors since it is already contaminated
Correct answer: Store it in a dedicated contaminated refrigerant cylinder and send it to a reclaimer
Contaminated refrigerant must be stored separately in a dedicated cylinder labeled for contaminated refrigerant and sent to a certified reclaimer; venting is never permitted.
Question 5: What color is used to identify the HIGH-SIDE hose on a standard A/C manifold gauge set?
- Blue
- Yellow
- Red (Correct answer)
- Green
Correct answer: Red
The high-side hose is red, the low-side hose is blue, and the center utility hose is yellow — this is the standard industry color coding.
Question 6: What is the purpose of evacuating an A/C system with a vacuum pump before recharging?
- To increase system pressure for leak testing
- To remove moisture and non-condensable gases (Correct answer)
- To circulate compressor oil through the system
- To cool the condenser before refrigerant is added
Correct answer: To remove moisture and non-condensable gases
Evacuation removes moisture and air (non-condensable gases) from the system; moisture combines with refrigerant to form acids that damage A/C components.
Question 7: Which type of oil is required for use in R-1234yf A/C systems?
- Mineral oil
- PAG (Polyalkylene Glycol) oil (Correct answer)
- POE (Polyolester) oil
- Alkylbenzene oil
Correct answer: PAG (Polyalkylene Glycol) oil
R-1234yf systems require PAG oil, the same type used with R-134a, though the specific viscosity grade must match the manufacturer's specification.
ASE Refrigerant Recovery, Recycling, and Handling 1
Which refrigerant has largely replaced R-134a in newer vehicle A/C systems due to its lower global warming potential?