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How To Replace A Defective Well-Pressure Switch

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If your home's water supply is from a well onsite, and you are experiencing difficulty with your water pressure, then the first thing you should do is check the water-pressure switch. This component is prone to wearing out over time and will need to be periodically replaced. Fortunately, replacement is simple and doesn't cost much. Below is a step-by-step guide to replacing this all-important component.


  • Pipe wrench or adjustable wrench
  • Pipe thread tape
  • Screwdriver
  • Voltage detector
  • Brass wire brush

Step-by-step guide

1. Disconnect power to the pressure switch and drain the tank — The pressure switch is powered by the same circuit that provides service to your well pump in most cases. It is essential to disconnect power to the pressure switch before attempting replacement; otherwise, you run the risk of getting a severe electrical shock. Flip off the circuit breaker to the pressure switch, then open the pressure tank's drain valve to empty the tank. Once the tank empties, double-check to be sure the electricity is disconnected by using a non-contact voltage detector.

2. Remove the old pressure switch — After disconnecting the power, remove the terminal screws holding the electrical wires in place, then pull the wires away from the switch. Be sure to mark the wires using tape or some other means to know where each one is attached. Next, use a pipe wrench or adjustable wrench to remove the old switch from its mounting location. Turn the coupling holding the pressure switch in place in a counterclockwise direction to loosen it.

3. Install a new switch — Once the old pressure switch has been removed, clean away any residue on the threads of the coupling using a brass wire brush. Next, wrap a couple of turns of pipe thread tape around the threads and carefully place the new pressure switch onto the threads. Turn the pressure switch clockwise by hand until it begins to tighten, then finish tightening with a pipe wrench or adjustable wrench. Be careful not to apply excessive force to the switch or coupling in order to prevent damaging either of these components. Reattach the wires to the terminals on the new switch and tighten the screws to ensure a good connection.

4. Restore power and test the pressure switch — After replacing the pressure switch, close the drain valve on the tank to prevent water from escaping once it is under pressure. Next, restore electrical service, and the pump should start adding water to the tank. Once the water pressure reaches the preset level as indicated on the pressure switch, the pump should shut off. However, if water pressure doesn't seem adequate after replacing the switch, reference the instructions included with the switch to determine how to increase the preset pressure levels.

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