Which device helps to shut down the compressor under low refrigerant conditions?

The low pressure switch is designed to monitor the pressure of the refrigerant in the system. When the refrigerant level drops below a certain threshold, indicating low refrigerant conditions, the low pressure switch activates and shuts down the compressor to prevent damage. Operating a compressor with insufficient refrigerant can lead to overheating or mechanical failure, so this safety mechanism is crucial in protecting the system.

Other devices mentioned do not serve this specific function. For example, the high temperature cut-off switch is focused on monitoring temperature levels and protecting the system from overheating conditions rather than addressing low refrigerant levels. The thermostatic valve regulates the flow of refrigerant based on temperature but does not control the compressor's operation based on refrigerant pressure. A flow meter measures the flow rate of refrigerant but does not have a shutdown capability to protect the compressor under low refrigerant conditions. Thus, the low pressure switch is the key device responsible for shutting down the compressor to maintain safe operating conditions.