The most cost-effective method of recovering refrigerant from a low-pressure chiller with more than 500 lbs. of refrigerant and to meet EPA requirements is to recover the refrigerant using what protocol?

Correct Answer: Option B — liquid recovery using a liquid pump, followed by vapor recovery using a vacuum pump based recovery unit

Extracting bulk liquid refrigerant first via a dedicated liquid pump drastically reduces recovery time for large inventories, leaving a smaller residual vapor volume to be evacuated efficiently by a vacuum-based recovery unit per EPA guidelines.