What is the primary role of a solenoid valve in a refrigeration circuit during the pumpdown process?

A solenoid valve plays a crucial role in the pumpdown process of a refrigeration circuit by closing the liquid line. During the pumpdown operation, the system is designed to remove refrigerant from the evaporator and store it in the receiver or other storage devices. When the solenoid valve closes, it effectively stops the flow of refrigerant in the liquid line, which allows the system to reach a low-pressure state. This action is essential for protecting the compressor and ensuring efficient operation during the refrigeration cycle.

In this context, closing the liquid line means that the refrigerant is prevented from entering the evaporator until it’s needed, allowing the compressor to operate without flooding and helping maintain system efficiency. This functionality supports the overall goal of pumpdown: to maintain low pressure in the evaporator and ensure that the refrigerant is safely contained in the system when not in use.