How To Replace The Upper Thermostat In A Water Heater

12 April 2016
 Categories: , Blog

Is your water heater output inconsistent on how much hot water you receive or how hot the water can get? Your water heater might have a malfunctioning upper thermostat. The upper thermostat tests the water temperature at the top of the tank. When the correct temperature is reached, it tells the system to start heating the bottom of the tank.

You can test the upper thermostat with a multi-meter. If you have already tested the thermostat and found it wasn't working, replacing the part isn't difficult.

Things You Need:

  • Screwdriver
  • Electrical tape
  • Digital camera
  • New upper thermostat with cover

Step 1: Access the Upper Thermostat

Turn off the power to the water heater at the circuit breaker or unplug the unit.  

Locate the access panel on the side or rear of the water heater. Use a screwdriver to remove the fasteners holding the panel in place. Pull the panel off, set it somewhere safe and put the screws in your pocket or on a secure table.

There's a layer of insulation over the thermostat, but it should lift up like a door flap. Pull up the insulation flap and press it to the side of the water heater. Tape it into place with electrical tape to keep the flap out of the way while you work.

Use your screwdriver to pry up an edge of the plastic thermostat cover and pull it off. You can dispose of the cover since the new thermostat will come with its own.

Step 2: Unhook and Remove Upper Thermostat

Take a picture of the wires attached to the upper thermometer. Loosen the screws holding each wire in place. Note that you don't need to actually remove the screws; the wires can slip out once the screws are loose.

Locate the metal mounting brackets on each side of the thermostat. Pull the brackets forward. Remove the old thermostat from behind the brackets and discard it.

Step 3: Install the New Upper Thermostat

Place the new upper thermostat behind the brackets and then push the brackets backwards to secure it. Reattach the wires to the thermostat terminals using the picture if you need help on finding the right positioning. Tighten the screws to secure each wire. Set the thermostat dial to a temperature recommended by the manufacturer.

Snap the new plastic cover into place over the thermostat. Remove the tape on the insulation flap and push the flap into place over the thermostat cover. Retrieve the access panel and put it over the opening and secure it into place with the screws.

Restore power at the circuit breaker or plug. Allow your water heater time to warm back up and then test to see if the problem is solved. Still have issues? Call in a plumbing repairs service for advanced diagnosis.