The suction pressure control switch is responsible for what action in a refrigeration plant?

The suction pressure control switch plays a crucial role in the operation of a refrigeration plant by monitoring the pressure in the suction line. When the suction pressure drops below a predetermined level, the switch activates the compressor to turn on, allowing for refrigerant to circulate and maintain necessary cooling within the system. Conversely, when the suction pressure reaches a target level, indicating that the required cooling has been achieved, the switch will turn off the compressor.

This on-and-off operation helps to maintain the refrigeration system's efficiency and prevents issues such as over-cooling or excessive strain on the compressor. By responding dynamically to the pressure in the system, the suction pressure control switch ensures optimal operation of the refrigeration plant, thus making the answer that it causes the compressor to go on or off as required the most accurate choice.