What is a Pressure Switch?

A pressure switch is used to monitor changes in system pressure and turn on and off a water pump. A pressure switch detects when a predetermined pressure point is reached and opens or shuts an electrical switching element.

Air compressor pumps may also be controlled via switches. As a result, they are extensively used in various industrial applications to form or break electrical circuits at specific pressures or to power other devices such as alarms.

All pressure switches have the same cut-in and cut-out points. The cu-in point, known as the reset point, is activated by decreasing pressure and causes the pump to start. The cut-out point, known as the trip point, is activated by rising pressure and shuts off the pump.

Increase the cut-in and cut-out pressure by turning the large spring’s nut clockwise. Turn the nut counterclockwise to reduce the cut-in and cut-out pressure levels.

For precision and maximum switch life, the cut-in and cut-out set points should be in the centre of the working pressure range.

The differential, also known as the dead-band, is the difference or spread between the cut-in and cut-out positions. Most switches allow you to alter the difference between the cut-in and cut-out; however, other switches have fixed, non-adjustable differentials. For example, some applications need a larger or smaller gap between the pump-on and pump-off set-points. To make changes, turn the small spring’s nut clockwise to raise just the cut-out pressure. Counterclockwise rotation merely lowers the cut-out pressure.