How to Replace Water Heater Thermostat – Step-by-Step Instruction

A fail thermostat is a common reason why you’re not getting any hot water from your electric water heater. The good news is that replacing a thermostat isn’t difficult at all, and you won’t even have to drain the tank.

Here’s the procedure how to replace the water heater thermostat that applies to either the upper or lower thermostat on your water heater.

Replacing a Water Heater Thermostat – Intro

First, be sure the new thermostat is the same type of thermostat that you’re replacing. Keep in mind that the upper thermostats are usually not the same as the lower thermostat.

You should always check with the producer and order the thermostat for your specific water heater. Also, you’ll need a number two screwdriver, a flat blade screwdriver, and a voltmeter.

Step 1

Turn the power off to the water heater at the circuit breaker.

Step 2

Then remove the cover panel and installation to expose the thermostat. Move the reinforcing bracket and throw it away. You’ll also need to remove the plastic protective cover over the thermostat.

Step 3

Using a voltmeter verify that power has been disconnected. There should not be any power.
Touch one probe to grounded metal – the unpainted metal tank housing is a good location.

Touch the other probe to ALL thermostat terminals and both heating element terminals. The voltmeter should indicate no voltage at all times.

Step 4

Tag the wires before removing them from the screw terminals to eliminate incorrect wiring later, you can also take a before digital snapshot of the wiring for reference.

Step 5

Remove the thermostat by lifting it out of the retaining bracket and be careful not to pull too hard. Breaking the retaining bracket will require the entire water heater to be replaced.

Step 6

Replace the old thermostat with an identical new one. Be sure the back of the thermostat is pressing tightly against the tank because that affects the accuracy of the temperature reading.

Step 7

Rewire your tagged leads to the proper screw terminals, double-check to be sure your wire connections are correct and that they’re firm and tight, and replace the plastic protective cover.

Step 8

Adjust the new thermostat so the water temperature doesn’t exceed 120 degrees Fahrenheit.

Step 9

Replace the installation and cover panel. And you’re done.
Turn the power back on to the water heater at the circuit breaker. And about an hour, you’ll have plenty of hot water again.