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How to Replace a Well Pump Pressure Switch

Replace a cranky old switch in about an hour

FH11JUN_PRESWI_01-2Family Handyman
Replace a faulty well pump switch in about an hour; no special tools or skills required.

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Replace a faulty pump pressure switch

Photo 1: Shut off the power, then disassemble

Label each wire with tape. Then unscrew the conduit locking ring and pull the wires and conduit out of the switch.

Photo 2: Swap the switch

Unscrew the old switch and nipple. Replace with new parts.

Photo 3: Replace the pressure gauge

Slap your adjustable wrench around the flats on the gauge and unscrew it. Then screw in a new one and tighten it down.

Well Pump Pressure Switch Adjustment

Your well pump gets its marching orders from the switch mounted on the pressure tank. When the switch acts up (and they all do eventually), you’ll see all kinds of strange behavior (pump won’t turn on, turns on erratically or won’t shut off). Replacing the pressure switch is cheap and takes only about an hour.

Diagnose a cranky switch by rapping on it with a screwdriver handle. If the pump runs (you’ll hear it click) or quits, you’ve nailed the problem. But even if it doesn’t respond, it’s still worth replacing the switch. Replace it with a new one (about $24 at rural home centers and amazon.com).

Switches come in three pressure ranges: 20 to 40, 30 to 50 and 40 to 60 psi. Always replace your switch with one of the same rating (usually printed inside the plastic cover of your old switch). Also buy a new pressure gauge (less than $10) and a 1/4-in. x 6-in. galvanized nipple.

Flip the breaker to the pump switch and check it with a voltage sniffer to make sure it’s off. Then disconnect the wiring (Photo 1).

Close the valve from the pressure tank to the house. Then drain the pressure tank. Next, remove the old switch (Photo 2) and gauge (Photo 3).

Wrap the pipe threads with Teflon tape and reassemble. Install the wiring, close the faucet and repower the pump.

Video: Fixing a Dead Well

Video: Fixing a Well Pressure Tank

Required Tools for this Project

Have the necessary tools for this DIY project lined up before you start—you’ll save time and frustration.

  • 4-in-1 screwdriver
  • Adjustable wrench
  • Non-contact voltage tester
  • Pipe wrench
  • Pliers