5 Easy Steps to Replace a Water Heater Thermostat

Easy Steps to Replace a Water Heater Thermostat

When your water heater supplies boiling water, it becomes essential to replace the water heater thermostat. In other words, your water heater can malfunction, and in that case, you do not need to replace the complete water heater, but the thermostat is the most likely issue.

 Check Out Our Plumbing Services

You need to understand the working of a thermostat and the indications of faults. This article will illustrate the working of a thermostat and its problems. Read the article thoroughly to learn about the replacement of thermostats.

Working methodology of a Water Heater Thermostat

The thermostat controls the electricity supply depending on the water temperature. You preset the desired temperature on your thermostat, and the thermostat ensures water is dispatched at that temperature. Usually, all modern heaters have two thermostats and two heating elements.

One thermostat manages the lower temperature threshold, and the other for the higher temperature. This way, you can judge which thermostat needs to be fixed. Therefore, detect the faulty thermostat through water temperature, and remember the instructions explained in the later sections.

Indications of a Faulty Thermostat

When the thermostat of a water heater does not work correctly, you can confront scalding hot or icy cold water running through your faucet. Therefore, it is the right time to check the thermostat and replace it if needed.

Common Water Heater Thermostat Problems

This section will elaborate on the common thermostat problems that you can come across.

The Set Temperature is Low

The set temperature will likely be low when you buy a new water heater. Because the manufacturers ensure you do not get burning hot water. Therefore, check the set value of the thermostat. If it is different from your demand, you can change it.

Improper Installation

This issue can happen if your plumber needs to be qualified more and improperly wires up the water heater. Resultantly, you can face multiple problems with your water heater. Therefore, make sure to check the working of your heater before you pay the plumber.

Bad Quality Heating Element

The heating element causes the water in the tank to get colder than normal. This is a significant issue because until you replace the element, the water in the tank will not get hot. So if you observe an abrupt change in your water’s temperature, you may have a bad heating element.

How to Replace a Water Heater Thermostat?

After having enough discussion on the thermostat issues and their indications, we can finally move to the replacement procedure of a thermostat.

Electrical Water Heater Thermostat Replacement


Turn Off the Input Supply

It would help if you always disconnected the heater from the supply to experience safe plumbing. You also have to remove the access panel for the thermostat replacement. If you have a voltmeter or DMM, ensure no voltages at the input connection point.

Locate and Disengage the Thermostat

You can find the thermostats in place by a special bracket that holds it tightly against the tank, permitting the thermostat to sense the internal water temperature. Gently take one side of the bracket out while turning that side of the thermostat upwards to avoid the bracket from fitting in place again. Do the same for the other side. If you have a dual thermostat unit, repeat the same procedure for the second thermostat.

Replace a Water Heater Thermostat


Replace the Thermostat and the Bracket

While you take the thermostat off, the bracket will likely get damaged, and you need to replace both. The best way is to match the components of the new and old thermostats. Ideally, the components of both thermostats should be identical.

Complete the Replacement

After checking the new thermostat and the bracket, slide the new bracket in and make sure it is well-positioned. After placing the bracket, put the new thermostat and tightly position it inside the holding bracket.

It’s time to put the access panel and the cover back in place. Check the water heater and run the faucet to feel the hot water. If the water is around the desired temperature, you did the job, or you need to call a plumber to fix the issue.

Replacement of Gas Water Heater Thermostat

The heaters operating on gas usually have a control valve that contains the thermostat and a heat-limiting component. Mostly, you can find this valve assembly outside the unit near the bottom. Therefore, if you have to replace the thermostat, you must completely replace this assembly. You can easily replace the older one with the fresh counterpart.


It is a tedious yet doable task to replace a water heater thermostat. Most people still need to replace the thermostat themselves, considering it challenging. However, identifying the fault in the water heater thermostat and replacing it is simple if you get some background of the thermostats and their working.

Scroll to Top