EPA 609 Retrofitting R-12 Systems to Alternative Refrigerants — Questions and Answers
Question 1: When an R-12 MVAC system is retrofitted to R-134a, what must be done with the original R-12 service fittings?
- They can stay in place so either refrigerant can be used
- They must be converted to R-134a-specific fittings or permanently disabled (Correct answer)
- They only need a colored cap
- They must be moved to the low side of the system
Correct answer: They must be converted to R-134a-specific fittings or permanently disabled
EPA SNAP rules require each substitute refrigerant to have its own unique service fittings. Old R-12 fittings must be replaced with R-134a fittings or permanently disabled so nobody can charge the wrong refrigerant into the system.
Question 2: Which of the following must appear on the label applied to a retrofitted MVAC system?
- The vehicle's original sale price
- The customer's phone number
- The new refrigerant, retrofit date, technician or shop name, and lubricant type (Correct answer)
- Only the vehicle identification number
Correct answer: The new refrigerant, retrofit date, technician or shop name, and lubricant type
The retrofit label tells future technicians what is in the system: the refrigerant used, the amount charged, the lubricant type and amount, the date of the retrofit, and who did the work.
Question 3: Before retrofitting an R-12 system to R-134a, what must the technician do with the remaining R-12?
- Vent it, since the system is being converted anyway
- Leave it in the system to mix with the R-134a
- Recover it with approved equipment (Correct answer)
- Release it slowly over 24 hours
Correct answer: Recover it with approved equipment
Venting refrigerant is illegal under the Clean Air Act. Any R-12 left in the system must be recovered with EPA-approved equipment before the conversion starts.
Question 4: Why is the lubricant usually changed or flushed during an R-12 to R-134a retrofit?
- Mineral oil used with R-12 does not mix well with R-134a, so PAG or POE oil is used (Correct answer)
- R-134a systems run without any lubricant
- Mineral oil makes R-134a flammable
- EPA requires the oil to be changed every year
Correct answer: Mineral oil used with R-12 does not mix well with R-134a, so PAG or POE oil is used
R-12 systems use mineral oil, which does not mix well with R-134a and returns poorly to the compressor. Retrofits normally switch to a compatible synthetic lubricant such as PAG or POE.
Question 5: Under EPA SNAP rules, is it acceptable to 'top off' a partly charged R-12 system with R-134a?
- Yes, as long as the system is low
- Yes, if the vehicle is older than 1994
- No, refrigerants must not be mixed, and a full retrofit is required to switch (Correct answer)
- No, unless the customer signs a waiver
Correct answer: No, refrigerants must not be mixed, and a full retrofit is required to switch
Mixing refrigerants contaminates the system and the recovery equipment. Moving to a substitute refrigerant requires a full retrofit that meets SNAP conditions: unique fittings, a label, and recovery of the original refrigerant.
Question 6: Compared with the original R-12 charge, how is a retrofitted R-134a system usually charged?
- With about 150% of the R-12 amount
- With exactly twice the R-12 amount
- With roughly 80-90% of the original R-12 charge, or the retrofit kit's specification (Correct answer)
- Until the sight glass shows constant bubbles
Correct answer: With roughly 80-90% of the original R-12 charge, or the retrofit kit's specification
R-134a works at different pressures and densities than R-12, so retrofitted systems are normally charged with less, often 80-90% of the R-12 specification, following the manufacturer's retrofit guidance.
