How To Replace An Electric Water Heater Thermostat

If  you have a problem with water temperature in your business or residence, the hot water heater thermostat is likely the culprit. Electric water heaters have two thermostats to correspond with the tank size. The elements shut off after the water reaches a preset temperature. 

In some cases, defective thermostats could cause the water to get scalding hot, posing risks of burns, which you don't need to happen. It is easy to replace the thermostats by following these tips.

Prepare to Work

To complete this project, you need

  • work gloves
  • voltage tester
  • regular and small screwdriver
  • painter's tape
  • replacement thermostat

Older hot water heaters could have fiberglass insulation. Don't touch it with your bare hands, since it may irritate the skin.

Before you replace the thermostats, check the limit switch of the top thermostat, if applicable. The switch shuts off if the water gets too hot, which depresses the button. Push the red button to reset, and test the water heater again.

Shut off the power to the hot water heater from the breaker, or shut off the main power supply. Run a voltage tester over the breaker to ensure there is no current.

Remove the Old Thermostat

Detach the access panel screws with the screwdriver, and set them aside. Dual thermostat models have an access panel for each thermostat. It is ideal to replace dual thermostats at the same time. Remove insulation, if applicable, and set it aside.

Stick painter's tape next to terminal screws with wires, and assign the screw a number. Wrap painter's tape around the wires attached to a screw. Write the number on the tape. 

Brackets secure the thermostats. Rotate that side of the thermostat up to remove the bracket. 

Use the screwdriver to detach the mounting screws, and detach the wires from the thermostats. Pop off the bottom clips by hand. 

Remove the thermostats, but don't discard them yet. Take them with you to help buy a replacement. Replace damaged brackets, if needed.

Install the New Thermostat

Mark the screw terminals on the new thermostat to correspond with the ones on the old thermostat. Attach the wires to the proper screw terminals, and tighten the connections. Remove the tape.

Insert the protective cover, and ensure the red button is accessible through the hole. Rotate the dial to one-hundred and twenty degrees using the screwdriver. Reinstall the insulation and access panel.

Restore power, and test the hot water heater. If the water heater still doesn't work, or if you don't trust your skill, contact a company of commercial plumbers.