Prior to recovering the vapor refrigerant in a low-pressure chiller, what should have been completed?

In the context of recovering vapor refrigerant in a low-pressure chiller, the necessary step prior to recovery focuses on ensuring the system is prepared for refrigerant extraction without causing potential harm to the system or violating regulations. The correct choice emphasizes the importance of recovering liquid refrigerant before vapor recovery. This sequence is crucial for a few reasons.

First, recovering the liquid refrigerant minimizes the amount of vapor that remains in the system, which helps to prevent an excessive buildup of vapor pressure that could lead to issues during recovery. Liquid refrigerant can be more easily recovered and managed, as it allows for a more controlled and efficient recovery process. By removing the liquid first, the technician ensures that the system is not under undue pressure from vapor once the recovery process begins.

Additionally, handling the liquid refrigerant first can assist with reducing the overall volume of refrigerant in the system more effectively, as vapor recovery is generally less efficient than liquid recovery. When the liquid is removed, it also mitigates the risk of oil carryover that can occur when vapor refrigerants are recovered without prior liquid removal. Proper management of refrigerant phases is crucial for compliance with safety and environmental regulations.

In summary, focusing on liquid recovery ensures the safe and efficient operation of the recovery process before