Why should a technician wait a few minutes after reaching the required vacuum on an R-22 system before opening it?
Recovery techniques · EPA 608 Type II. The correct answer, and the reasoning behind it.
Recovering liquid first, speeding recovery, and avoiding cross-contamination.
The question
Why should a technician wait a few minutes after reaching the required vacuum on an R-22 system before opening it?
- To let the recovery machine cool down
- To let the compressor oil drain back
- To see if the pressure rises, showing refrigerant remainsCorrect answer
- To let any moisture boil out of the refrigerant before opening
Why “To see if the pressure rises, showing refrigerant remains” is correct
EPA's outline calls for waiting after reaching the recovery vacuum to see if system pressure rises. A rise means liquid refrigerant is still in the system or refrigerant is coming out of the oil.
Source: EPA: Test Topics; 40 CFR 82.156(a)
Why the other answers are wrong
- To let the recovery machine cool down — Cooling the machine is not the purpose of the wait.
- To let the compressor oil drain back — Oil drain-back is not what the check is for.
- To let any moisture boil out of the refrigerant before opening — The check looks for refrigerant, not moisture.
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Unofficial, not affiliated with the EPA or any EPA-approved certifying organization. Questions are original practice written from public EPA material, not real exam questions.