11 Steps on How to Test Water Heater Thermostat

A White heating radiator on the wall.

Many homeowners like us nowadays are not informed or even familiar with what is happening in our home. When confronted by issues on our homes we have, we do not even take the time to figure it out by ourselves. More often than not, I pick up the phone immediately and rely on repairmen to fix my problems. But, what if there is no available repairman to help save the day?

That is when the knowledge on how to DIY comes in. Imagine that we’re in a situation during winter, snowed in with all roads blocked and the repairman cannot come to our rescue? What are we going to do? With this thought in mind and my paranoia kicking in, it is time to learn how to go about taking care of that thermostat and familiarizing myself with how it works.

Main Parts of an Electric Water Heater

There are three main parts to an electric water heater – a heating element, a thermostat, and a switch that prevents it from excessive heating. Right now, my focus will be the thermostat. It is the part that makes sure the desired temperature in my bath or for washing dishes is followed.

A water heater’s thermostat allows us to maintain a specific temperature to our liking. It allows the water heater to turn on and off while maintaining the specific temperature set. If the thermostat is not working properly then the heater does not work correctly as well. It could be that the water heater is cannot turn off or it does not get power to turn on.

An electric water heater has two thermostats. One on top and one on the bottom. And each one controls two different heating elements. You will notice that when the top thermostat is broken, the water that comes out would be cold at first and then turn cold. When the bottom thermostat is broken, the hot water that comes out would turn cold. Having both thermostat working means that water will be on a steady hot temperature. Those are the signs you can look out for.

If this is the case, one of the thermostats is not working. We will have to know a way to test a water heater’s thermostat to find the actual unit that has a problem. When we’ve done this, we would be able to fix it all by ourselves.


How to Know if Your Water Thermostat is Faulty

Water ThermostatApart from water not attaining its desired heat as it was set may not be the only problem that can happen. There is the possibility that the water heater will not turn at all. It is best to test the thermostat first to determine which one we need to replace first.

Knowing how to test a water heater’s thermostat is not only easy but it can be very quick to do. All we have to know are the steps. Before we take a peek at the steps, do not be intimidated. It looks like a lot at first, but if we follow accordingly, we will understand a water heater much better.

Here are the easy 11 steps we need to follow to test if our water heater’s thermostat is working or not:

  1. Turn on the tap and see if there is any slight change in temperature at all. If nothing is happening and it just remains cold to the touch, then it is time to see which one of thermostat needs changing (because remember, there are two thermostats in our water heater).
  2. Make use of a multimeter or also known as VOM (volt-ohm-milliammeter). A multimeter is an electrician’s common tool. It is an electronic measuring instrument. It measures voltage, current, and resistance of your electronic device or power source. We will use this to determine which one of your thermostats is faulty.
  3. Set the scale on the multimeter to the lowest ohm point. Then touch both pins on the multimeter together and it should read zero.
  4. Then place each pin with the two ends of the water heater’s power plug. If the multimeter display shows no reading, then that means the thermostat has a problem.
  5. Make sure that the water heater is turned off or make sure to turn off the circuit breaker from the switch box that serves the water heater.
  6. Remove the upper and lower access panels. The access panel is located on the side of the electric heater and usually has an electric warning label. Do not be scared of this. As long as we know what you we doing, we will be okay. Just continue following these steps.
  7. Remove any insulation covers. It can be pulled out very easily. But be careful not to pull out any of the wirings inside. Do this gently and with care.
  8. Again, set the scale on the multimeter to the lowest ohm point. Then touch both pins on the multimeter together and it should read zero.
  9. Place one of the pins on the left screw terminal with the white wire and the other pin on the terminal above it. The reading on the multimeter should show zero. If there is something else being displayed, then that means the thermostat is a problem.
  10. The upper thermostat has a reset button that might act sometimes because the thermostat has not been calibrated for a long time. We will hear a click once you’ve turned it to the lowest setting.
  11. Leaving the upper thermostat to the lowest setting, proceed to test the lower thermostat. The lower thermostat must be turned to the highest setting. Touch one of the pins of the multimeter to each terminal on the lower thermostat. Again, the reading must be zero. If the water temperature is cold, the multimeter will have no reading. If it displays something other than those two results, that means the thermostat is broken and needs replacement.


If we will follow these steps, we will not go wrong. What is happening in our own home should be in our control. Doing these tests allows us to take charge of our home and the warmth inside it.

We don’t always have to call someone to help us solve your water heater problems if we can do the tests yourself. we should not let yourself get intimidated. Sometimes, it only needs a little adjustment, and we are well capable of doing that.

Knowing how to test our water heater’s thermostat saves you money and time. Sure, we will have to invest in a multimeter. But we have the keyword there, invest.

A multimeter has a lot of uses for everything electrical in your home to test if they are working. We’ve started with our water heating system – do not let yourself stop there. Knowing how to test our water heater’s thermostat will also help us understand how to take better care of our water heater system and how to make it last longer. We might even want to know how to make our repairs and replace our thermostat when needed.

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