A pressure switch is a device that senses water pressure and turns a pump on or off to maintain a desired pressure range in a water system. In a well pump system, the pressure switch is responsible for starting and stopping the pump to maintain water pressure in the home or building. Setting the pressure switch correctly is essential for the proper operation of the well pump system.
The pressure switch is typically mounted on the well pump or near the pressure tank. It has two main adjustments: the cut-in pressure and the cut-out pressure. The cut-in pressure is the pressure at which the pump turns on. The cut-out pressure is the pressure at which the pump turns off. The difference between the cut-in and cut-out pressure is called the differential. The differential is typically set between 2 and 4 psi.