What should be on and what should be off during vapor removal from a low pressure refrigeration system?

• A. The system water pumps, the recovery compressor and the recovery condenser water should all be on
• B. The recovery compressor should be on only
• C. All pumps off
• D. Water pumps on but condenser off

Answer: (A)

During vapor removal from a low‑pressure system, the goal is to pull refrigerant vapor out and condense it into liquid in the recovery cylinder. To do this safely and efficiently, the recovery unit’s compressor must be running to extract the vapor, and the recovery condenser needs to be actively cooling so that the vapor can be condensed. That cooling requires circulating water, so the water pumps should be on as well. With the compressor, condenser, and cooling water all active, vapor is drawn out and condensed rather than staying as vapor or causing overheating.

If you run only the compressor, there’s nothing to remove the heat, so condensation won’t occur and pressure can rise. If pumps are off, there’s no cooling for the condenser, and if the condenser isn’t on, vapor can’t be condensed. Hence, all three—compressor, condenser, and water pumps—should be on.