The pressure switch is the device that turns the pump on and off during the pumping cycle by sensing the pressure in the pump system.The pressure switch has a set of points that makes the electrical circuit to the pump at the set cut-in pressure and breaks the electrical circuit when the set cut-out pressure is reached to turn the pump on and off.
The common pre set pressures on pump switches are 20psi cut-in/40psi cut-out or 30psi cut-in/50psi cut-out or 40psi cut-in/60psi cut out with other switches available for special requirements. Most pressure switches are adjustable.
Pressure Switch Adjustment
To adjust most common pressure switches (like the Square D brand depicted above) for a higher range (higher cut-in and cut-out pressure with the same differential) turn the center adjustment nut with the large spring clockwise. For a lower range turn the nut counter clockwise. To adjust the differential turn the offset adjustment nut with the small spring clockwise for higher cut-out pressure or counterclockwise for lower cut-out pressure. After pressure adjustment, test the pump cycle several times to ensure you have the proper settings with the pressure gauge on your system.
Some pressure switches (like the one depicted below) have a low water cut-off safety to keep the pump from running and prevent damage if there is not water available for pumping or pressure is lost. The pump will not cycle until the manual reset lever is reset after the problem is corrected. The lever must be held down until sufficient pressure is achieved in the system then the switch will cycle automatically.
Pressure Switch With Low Water Cut-off
If you have a pressure switch different than the types above contact ABC for assistance.