After the liquid has been recovered from a 180-pound R-410A system, what must still happen before the system is opened?

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

After the liquid has been recovered from a 180-pound R-410A system, what must still happen before the system is opened?

• ANothing; removing the liquid is enough
• BThe remaining vapor must also be recoveredCorrect answer
• CThe system must be charged with nitrogen to 50 psig
• DThe oil must be drained first

Why “The remaining vapor must also be recovered” is correct

Recovering liquid first only speeds the job. The rule requires all the refrigerant, liquid and vapor, to be evacuated to the Table 1 level, which for this high-pressure system under 200 pounds is 0 inches of Hg vacuum.

Source: 40 CFR 82.156(a); 40 CFR 82.156(a), Table 1; EPA: Test Topics

Why the other answers are wrong

• Nothing; removing the liquid is enough — Vapor left in the system would be released when it is opened.
• The system must be charged with nitrogen to 50 psig — Nitrogen does not replace recovering the refrigerant.
• The oil must be drained first — Draining oil is not required before every opening.

Practice more of this

More EPA 608 Type II practice questions, or see every EPA 608 practice test.