How to Adjust Square D Pressure Switches
- 1). Remove all electrical power from the device the pressure switch is controlling. This may entail shutting off the circuit breaker or pulling the fuse that supplies power to the electrical circuit.
- 2). Use the wire pliers to remove the top protective cover of the pressure switch. There is a small nut located top and center on the cover. Turn the nut in a counterclockwise direction to loosen. Pull the cover from the switch housing.
- 3). Observe the two springs on the pressure switch unit. There is a large spring with a ½-inch nut and a small spring with a 7/16-inch nut.
- 4). Turn the large spring nut in a clockwise direction to raise the overall pressure on-and-off range. Generally, a water pressure system will operate in the range of turning the water pump on when the pressure falls below 30 PSI (pounds per square inch) and turns the pump off when the pressure exceeds 50 PSI. When the nut is turned clockwise, it will raise the pressure on-and-off range. A counterclockwise direction will lower that range.
- 5). Use the 7/16-inch end wrench for adjusting the smaller spring pressure adjustment. Turn the smaller spring nut in a clockwise direction to raise the cut-off pressure only. This adjustment affects only the pump-off operation. Do not loosen (counterclockwise turn) the nut too much. This will lower the cut-off range into the cut in pressure. At this point, the pump will never shut off, and damage may occur to the pump and plumbing pipe system.
Source...