The pressure switch is an integral part of a private home well pump's system. The pressure switch controls the operation of the well pump, which delivers water to the household. The pressure switch is composed of an internal spring mechanism that is directly connected to a set of electrical contacts. Over time, the spring mechanism weakens, along with an electrical malfunction of the contacts.
Shut off the electricity to the well pump system. Switch off the circuit breaker or remove the fuses that supply the electrical power.
Access the switch mechanism by removing the cover to the pressure switch. Turn the top screw cap in a counterclockwise direction with the plumbing pliers. The switch is directly connected to the plumbing pipe system of the water well. A set of wires also enters and exits the switch.
Feel under the switch housing for leaking water or water leaking from the mechanism itself. If water is leaking under the switch's plumbing connection, fit the jaws of the plumber's pliers on the brass fitting. Turn the switch one revolution clockwise to tighten it. If water is leaking from the internal mechanism, the switch is bad.
Observe the two sets of electrical contacts and the screw terminals that connect the wires. If the contacts are held open and there is no water pressure, attempt to cycle the switch by pulling the contacts open. This may dislodge the internal spring. If the switch closes, turn the power back on. If the contacts remain open, and there is no water pressure, the switch is bad.
Allow the pump to fully cycle by opening a nearby water faucet. Do not touch any part of the switch while it is energized. If the switch opens and closes, it may have been temporarily stuck due to debris. If the switch fails to close when the pressure drops, the internal spring is bad. The switch requires replacement. If large electrical sparks emit from the contacts, remove power immediately.
Inspect the contact's mating points. If the small metal discs are black with carbon, pry them apart with your fingers. Feel the discs with your fingertips. If small pits are present, the contacts are bad; replace the switch.