What device is responsible for turning the compressor on and off?

The device that is primarily responsible for turning the compressor on and off in a refrigeration system is the pressure switch. This component monitors the pressure of the refrigerant within the system and automatically activates or deactivates the compressor based on predefined pressure settings.

When the pressure falls below a certain threshold, the pressure switch will signal the compressor to turn on, allowing the system to resume cooling. Conversely, when the pressure reaches a predetermined upper limit, the pressure switch will deactivate the compressor to prevent potential damage from excessive pressure buildup. This automatic regulation is crucial for maintaining the efficiency and safety of the refrigeration system.

While the other options serve important functions in a refrigeration system, their roles differ. A low-pressure switch specifically monitors low-pressure scenarios and may not control the compressor in high-pressure situations. A thermostat functions by sensing temperature and controlling the entire heating or cooling process based on temperature needs rather than direct pressure measurements. A flow switch monitors the flow of refrigerant or water within the system and can prevent the system from running if the flow is inadequate, but it does not directly control the compressor based on pressure readings.