When recovering R-22 from a 200-pound system, why is it best to remove liquid refrigerant first?

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

When recovering R-22 from a 200-pound system, why is it best to remove liquid refrigerant first?

• ALiquid recovery moves refrigerant much faster than vaporCorrect answer
• BLiquid cannot be recovered after vapor
• CIt keeps the oil in the system
• DIt removes the need to reach the required recovery vacuum

Why “Liquid recovery moves refrigerant much faster than vapor” is correct

EPA notes that recovering liquid at the start speeds up the process. A given volume of liquid holds far more refrigerant than the same volume of vapor, so most of the charge moves quickly before the slower vapor phase.

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

Why the other answers are wrong

• Liquid cannot be recovered after vapor — Liquid can still be recovered later; it is just slower to leave it.
• It keeps the oil in the system — Recovering liquid first is about speed, not keeping oil in place.
• It removes the need to reach the required recovery vacuum — The appliance must still reach the Table 1 level after the liquid is out.

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