What is the function of a level switch that closes on 'low'?

The function of a level switch that closes on 'low' is primarily to activate the alarm system when levels are low. This type of switch is designed to monitor the liquid level within a tank or vessel and provides critical feedback for operational safety. When the level drops below a predetermined threshold, the switch closes and typically sends a signal to the alarm system, alerting operators that the liquid level is insufficient.

This is crucial in industrial refrigeration systems where maintaining proper liquid levels is vital for effective operation and safety. If the level gets too low, it can lead to issues such as refrigerant starvation, which can harm compressors and other components of the system. While other roles such as maintaining a consistent water level, signaling adequate refrigerant levels, or ensuring efficient compressor operation are important, they do not focus specifically on alerting personnel about low levels, which is the key function of a level switch that closes on 'low'.