How to Repair and Replace a Well Pump Pressure Switch

Water Well Pump and Pressure Switch

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Obtaining water from your own water well can be beneficial since it gives you control of your water quality and it provides independence from municipal water systems. Yet these rewards come with costs, and one significant cost is the maintenance of the system. From the foot valve at the bottom of the well to the faucet at the sink, every piece of this well system is your responsibility to keep running efficiently.

When your well pump is broken, the issue can often be traced to one part: the well pump pressure switch. This switch senses the need for water and triggers the electric pump to turn on or off. The pressure switch is one of the most common failure points in water wells' physical systems. Fortunately, the pressure switch is also easy to repair and replace.

Safety Considerations

Electrical power runs through your well pump pressure switch. Before repairing, replacing, or even examining the switch inside its housing, be sure to turn off the power to the pump at the electrical service panel. Once you have removed the switch's outer housing, check again for the presence of electricity with a voltage tester. Also, wear eye protection when working on your well pump pressure switch.

Project Metrics

  • Working/Total Time: 60 minutes
  • Skill Level: Advanced
  • Material Cost: $30 to $50

What You'll Need

Equipment/Tools

  • Pressure gauge (optional)
  • Cordless drill with a driver bit
  • Wrench set
  • Vise-Grip wrench
  • Manual screwdriver
  • Voltage tester
  • Eye protection
  • Shop vacuum
  • Smartphone, camera, or masking tape and pen
  • Air compressor

Materials

  • Well pump pressure switch
  • Fine-grit sandpaper
  • Teflon tape

Instructions

  1. Remove the Pressure Switch Housing

    With a manual screwdriver or cordless drill, turn out the screws that hold the pressure switch housing in place. You should already have turned off the power running to the well pump.

  2. Document the Wiring Configuration

    If you are accustomed to wiring household outlets and ceiling lights, you have the basic know-how to disconnect and reconnect wires on a well pump pressure switch. However, this configuration can be confusing. Assuming that the existing wiring is correct, document its configuration by taking a picture or by labeling the wires with masking tape. It is easy to confuse the power supply wires with the pump motor wires since they look similar.

  3. Release the Pressure From the System

    Release the pressure by draining water from the tank. Confirm that the pressure has been released with the system's pressure gauge: It should read 0 PSI.

  4. Disconnect the Wires

    With the cordless drill or a manual screwdriver, turn out the screws holding the electrical wires to the contact points.

  5. Remove the Pressure Switch

    Clamp the Vise-Grip wrench on the lower nipple standpipe. Then, with a correctly sized wrench from the wrench set, turn the pressure switch out counter-clockwise.

  6. Install the New Pressure Switch

    Clean the water pipe's threads of any old pipe sealant or Teflon tape. Replace with new Teflon tape, making sure that you thread it on in the same direction that the pressure switch will be threaded on.

    Next, thread the new pressure switch onto the water pipe by hand at first, finishing by tightening with the wrenches as before.

  7. Install a New Pressure Gauge (Optional)

    While it is not necessary to replace the pressure gauge when replacing the pressure switch, many owners take this project as a convenient opportunity to upgrade the gauge.

  8. Replace the Wires

    Clean the wires with fine-grit sandpaper so that the copper is shiny. Replace the wires on their contacts and screw them down into place.

  9. Replace the Housing

    Replace the switch housing before turning on the electrical system again.

  10. Re-pressurize the Tank

At the top of the tank, add compressed air to the tank to bring the tank up to the correct pressure. Often, this is between 2 and 4 PSI below the switch's lowest limit, also called the cut-in limit. For example, for pressure switches rated at 40 to 60 PSI, you would pressurize the tank to 38 PSI. Be sure to consult the manufacturer's instructions for information about your system, though.

How to Repair a Well Pump Pressure Switch

Given the low cost of new well pump pressure switches and the ease of installation, many owners find it more prudent to entirely replace the switch than to repair it. However, a few simple repairs may keep your well pump pressure switch running longer.

Instructions

  1. Clean the Pressure Switch

    Because well pumps are often in poorly protected areas subject to the elements, the pressure switch can become clogged with debris, dirt, spiderwebs, insects, cocoons, and mold and mildew.

    After turning off the power, remove the pressure switch's housing. Thoroughly clean it out either with a shop vacuum or by blowing out the debris with an air compressor. If necessary, gently pull out the debris with a soft brush, such as an old toothbrush.

  2. Examine and Clean the Electrical Contact Points

First, turn off the power and double-check that no power is flowing to the switch.

  • Ensure that the wires are turned clockwise around the screws. Wires, especially stranded wires, are greatly compromised when they are turned counter-clockwise.
  • Check the metal contact points that open and close, thus triggering the system off or on, respectively. Fold a small piece of fine-grit sandpaper in half and push it between the contacts to clean burned or pitted contacts.
  • Check the nipple standpipe on which the pressure switch rests. Unscrew the pressure switch from the nipple pipe and make sure that it is not corroded or clogged with sediment.