Which order of steps is correct when recovering refrigerant from an R-11 chiller before a major repair?

Recovery techniques · EPA 608 Type III. The correct answer, and the reasoning behind it.

Liquid then vapor, heating oil, protecting water tubes, and high-pressure cut-outs.

The question

Which order of steps is correct when recovering refrigerant from an R-11 chiller before a major repair?

• ARecover liquid, then vapor, then wait to see if pressure risesCorrect answer
• BRecover vapor, then liquid, then open the chiller
• CRecover liquid only, then open the chiller once it reaches 0 psig
• DRecover vapor, add nitrogen, then recover liquid

Why “Recover liquid, then vapor, then wait to see if pressure rises” is correct

Removing the liquid first gets most of the charge out fastest. Vapor recovery then pulls the chiller to 25 mm Hg absolute, and a few minutes' wait shows whether liquid is still boiling off before the chiller is opened.

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

Why the other answers are wrong

• Recover vapor, then liquid, then open the chiller — Liquid should come first, and the pressure must be checked before opening.
• Recover liquid only, then open the chiller once it reaches 0 psig — A major repair needs 25 mm Hg absolute, which takes vapor recovery as well.
• Recover vapor, add nitrogen, then recover liquid — Nitrogen is not part of recovery, and liquid should come out before vapor.

Practice more of this

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