After recovering liquid refrigerant from a centrifugal chiller the next step is to?

• A. Recycle liquid
• B. Recover vapor
• C. Purge oil
• D. Store in cylinder

Answer: (B)

The key idea is that after you’ve removed the liquid refrigerant, a centrifugal chiller still contains refrigerant as vapor trapped in the system. To maximize recovery and prevent venting to the atmosphere, you switch to recovering the vapor. This continues until the system is effectively exhausted and the recovery equipment shows no more refrigerant being drawn.

Why not the other steps? Recycle liquid would imply you’re trying to put liquid back into the system, which isn’t the immediate goal after liquid has already been removed. Purging oil is a separate step used to remove refrigerant that’s dissolved in compressor oil, not the next action needed to finish recovering the refrigerant from the chiller. Storing in a cylinder is something you do after you’ve completed the recovery (both liquid and vapor) and are transferring the recovered refrigerant into the cylinder for transport or disposal. The immediate next step is to recover the remaining refrigerant in vapor form.