Which statement is true regarding oil loss during refrigerant recovery?

• A. Oil loss is minimized by recovering in the liquid phase
• B. Oil loss is not affected by the phase
• C. Recovering in the vapor phase minimizes the oil loss
• D. Oil remains in the system after recovery

Answer: (C)

When you recover refrigerant, oil from the compressor can be carried out with the refrigerant. The phase in which you recover matters for how much oil comes along. Pulling refrigerant as a vapor means you’re taking out gas first, before much liquid refrigerant and oil are entrained together. Oil tends to stay in the system (in the compressor and oil reservoir) rather than in the vapor stream, so the amount of oil that ends up in the recovered refrigerant is greatly reduced. That’s why recovering in the vapor phase minimizes oil loss.

Recovering as a liquid tends to drag more oil out with the liquid, leading to greater oil loss. Some oil will always remain in the system or in the equipment, but vapor-phase recovery minimizes how much oil is lost with the recovered refrigerant.