A shallow well jet pump's pressure switch regulates the amount time the pump motor runs. A well's pressure switch turns on the jet pump once the water pressure in the storage tank's bladder drops below a set low-limit and turns off the jet pump once the water pressure breaks the high-limit setting. Adjusting the pressure switch changes the high and low water pressure limits. Never adjust the pressure switch above the stage tank's recommended maximum level.
Turn off the electricity to the shallow well jet pump at either the shut-off switch or the circuit breaker. Most jet pump well systems have a shut-off switch near the jet pump. If not, use the the circuit breaker labeled "Well" as the power disconnects.
Remove the jet pump pressure switch's cover with the correct screwdriver, usually either a Phillips screwdriver or a 1/4-inch hex-head screwdriver. The pressure switch mounts to the side of the jet pump. The wires from the shut-off switch or circuit breaker enter the pressure switch's housing.
Open a faucet. This lowers the water pressure in the storage tank and prevents false pressure switch readings. Close the faucet when the water stops draining from the system.
Turn on the power to the pump.
Adjust the pressure switch's high-limit adjustment screw with a 3/8-inch hex-head screwdriver. The adjustment screw is the short screw located behind the wiring terminals. Turn the adjustment screw counterclockwise to reduce the pressure switch's setting. Turn the adjustment screw clockwise to increase the pressure switch's setting. The jet pump turns off once the water pressure reaches the pressure switch's high limit.
Open a faucet.
Adjust the pressure switch's low-limit adjustment screw, the long screw located next to the high-limit adjustment screw, with the 3/8-inch hex-head screwdriver. Turn the adjustment screw left, or counterclockwise, to reduce the pressure switch's setting. Turn the adjustment screw right, or clockwise, to increase the pressure switch's setting. The jet pump turns on once the water pressure drops to the set low limit.
Replace the jet pump pressure switch's cover.