Installing a water heater thermostat for an electric water heater is not a difficult task. You will need to obtain replacement thermostats before you begin.

Are you sure that the thermostat is bad? Before you conclude that they need to be replaced you should test them. See the article 'Testing Water Heater Thermostats' for more information on how to conduct a test. A common problem that may seem like the thermostat is a bad heating element. See the article 'Testing Electric Water Heater Elements' for more information.

Not quite sure what your problem is? See the article 'Troubleshooting Electric Water Heaters' for a complete discussion on all of the water heater problems.

Electric Water Heater Thermostat Function

The thermostats for an electric water heater serve two important functions. First they are used to set the teperature for the hot water in your tank. Most of the time you should stay with the factory settings. See the article 'Hot Water Heater Temperature Settings' for some guidelines and a discussion on the dangers of setting the temperature too high.

The second function is to sense when the water has cooled to the point where the elements need to be turned on to heat the water in the tank. Most hot water heaters only run one element at a time. So the upper element will need to get the water up to temperature before the lower one will engage. This method reduces the amp load that the water heater draws. The down side is that it takes longer to heat a full tank of cold water.

WARNING!! DO NOT WORK ON A WATER HEATER WITHOUT TURNING THE POWER OFF!!! WARNING!!!

Purchasing an Electric Water Heater Thermostat

The fist thing to remember is that most water heaters have two thermostats, an up and a lower. The upper one is the larger and more complicated of the two. The upper thermostat controls the lower one.

If you are going to the trouble of replacing them, you should replace them both.

Removing the Old Thermostat

There are two steps to removing the thermostat assembly. First you need to unhook the wires. Second you need to release the pressure on the spring clips that hold the thermostat in place.

Removing the Wires

The upper thermostat will have more wires attached to it. The reason for that is that the upper thermostat also controls the lower thermostat.

Installing the Thermostat

Slide the new thermostat behind the spring clips. Make sure it is snug. A loose thermostat will not sense the temperature correctly.

Do you have that picture? Are your wires tagged? Then hooking the wires back up is a snap.

Hook up the wires per the original connections. Replace the plastic cover and insulation. Then install the metal covers. At this point it is safe to turn the power back on. You should be getting the proper of level of hot water pretty soon.

Removing a water heater thermostat is not too difficult, once the preparation is complete. Double check with a tester to make sure the power is off before proceeding.

To work properly the electric water heater thermostat needs to be positioned firmly against the wall of the hot water tank. It is held in place by a spring steel bracket. There are no screws that actually hold it in place.

You have followed Steps One and Two, so the power is off and the cover plates have been removed. You have removed the insulation and the plastic shield. There are different wiring configurations depending on your model. You will want to tag the wires before you remove them.

In addition, I suggest that you take a picture of the wires. Remember that old 'a picture is worth a thousand tags' thing. Actually it was 'thousand words', but you get the idea. Take a digital picture with your phone or camera. You may thank yourself later.

Remove the wires when you have the proper documentation. You may need to pry back on the clips to get the thermostat loose. Don't bend them, you will be sorry. The new thermostat will need to be pressed tightly against the tank.

Some water heaters have a break away clip that acts as a further restraint. Are you baffled and can't get it loose. Check your owner's manual. If it has one of these, it is probably a newer model. Don't throw the old electric water heater thermostat away. You want to take it with you when you get the new one.

Adjusting a water heater thermostat is a little harder than adjusting the thermostat on your furnace. This thermostat is meant to be set once and left alone, usually, the factory settings are suitable.

Not sure if this is your problem? See the article 'Troubleshooting Electric Water Heaters' for a complete listing of all of the problems related to an electric water heater.

Too Little Hot Water

Are you thinking of raising the temperature because you don't have enough hot water? Raising the temperature is not the way to solve this problem.

It is likely that you have another issue. The thermostats themselves may be malfunctioning or you could have a burned out heating element. See the articles 'Testing Electric Water Heater Thermostats' and 'Testing Electric Water Heater Elements' for information on checking to see if these items are functioning properly.

Safety Concerns

For safety reasons the water temperature adjustments for your electric hot water tank are hidden under a couple of layers. Make sure you follow the 'turning off the power' guidelines for electric water heaters. You will be very near some wires that have serious current in them when you make this adjustment.

There is a danger in setting the temperature too high. Water that is set to 160 degrees will give you a lot of hot water. It can also cause a serious burn in less than a second. Especially when there are children in the home should temperatures be set conservatively. Most manufacturers recommend a temperature setting of 120 degrees. Your water heater is likely set by the factory to that temperature.

See the article on 'Hot Water Heater Temperature Settings' for information on the correct settings and why setting it too high can be dangerous. Do you really want to change it?

Shutting Down the Water Heater

You need to shut down the power to the water heater before you attempt to access the thermostats. See the article 'Shutting Down an Electric Water Heater' for more information. Pay particular attention to the segment on shutting off the power.

Double check and make sure the power is off at the heater and make sure you tag the breaker.

Locating the Thermostats

Most water heaters have two thermostats. The are attached to the side of the tank. The locations of the thermostats are beside two removable plates on the side of the water heater.

You have to remove the metal covers on the outside of the hot water tank first. Then you will find some insulation that has to be removed or pushed aside to expose the thermostats and elements. Most models have a plastic cover that serves as an additional protection. You will need to remove the plastic cover to make the adjustment.

Adjusting The Thermostat

There is a screw that the can be adjusted with a flat blade screwdriver. The heat descriptions may vary. It may have the actual temperatures. Some of them have letter designations (A, B, C), while others may have the words 'Warm' or 'Hot'.

Summary

It is not common to need to adjust the temperature on your electric water heater. The factory settings are adequate in most situations. If you are not getting enough hot water, raising the temperature is not the solution. You likely have another problem such as a 'burned out element' or a 'faulty thermostat'.

An obvious reason for interest in electric water heater thermostats is the temperature of your hot water. If you need to adjust the water temperature, the thermostat is the place to do it.

Most of the time, the thermostats get some interest when you have too little hot water or no hot water. The thermostats could be part or all of the problem.

Not sure if the thermostats are the issue? See the article on 'Electric Water Heater Troubleshooting' for descriptions of all the common problems and a listing for resources on how to fix them.

The thermostats are closely related to the 'heating elements' and testing and checking should inolve both components.

How Electric Water Heater Thermostats Work

An electric water heater thermostat tells the heating elements when to heat up. Most electric hot water tanks have two elements and two thermostats. The elements do not heat up at the same time. The top element heats the water first and then the bottom element kicks in.

The upper thermostat acts as a coordinator between the two elements. When the water in the top part to the tank is hot enough, it lets the lower thermostat go into action. When the lower thermostat senses the water is too cool it turns on the lower element. This happens only after the upper element has finished heating.

You need to do some testing to determine which element or thermostat is bad.

There is another reason you could be here. To adjust the temperature of the water you need to get to the thermostats. These thermostats are a little harder to adjust than your furnace is. There are a couple of things you need to do to expose them.

Electric Water Heater Thermostat - Information

The upper thermostat is around $20 to $25 and the lower one is $10 to $15. You will probably pay around $100 in labor to get them

How Hard Could It Be?

Replacing an electric water heater thermostat is not that hard of a job. You are dealing with some serious electricity and that adds a safety factor.

• Difficulty Level of: A Bit of Work
• Skill Level of: Determined Handyman

For and explanation of the terms in this section, see 'How to Use This Site'.

Check the Simple Things!

Try the reset buttons before you replace the thermostats. Each thermostat has one.

Do not work on the wiring for an electric hot water heater with the power on. Make sure the breaker is shut off and taped or locked in the off position. The current in a hot water tank can kill you. Replacing the wrong thermostat may still leave you without hot water or not enough hot water.

Electric Water Heater Thermostats - Safety Issues

Before you test or work on electric water heater thermostats or the water heater in general, you want to make sure that you have shut off the power to the water heater. The electrical power that heats the water can cause serious injury or even death.

See the article, 'Shutting Down an Electric Water Heater' and 'Electrical Safety Tips' for more infomation and the proper procedures to follow when working on an electric water heater.

Troubleshooting Electric Water Heater Thermostats

Is it safe to work on electric water heaters?

It is not safe to work on an electric water heater without taking certain precautions. Before you do anything, you should shut down the power to the heater. See the article 'Shutting Down an Electric Water Heater', and review the section on safely 'Shutting Off the Power'.

Water heater thermostats are connected directly to the hot water tank. The tank will likely be hot. See the section on 'Cooling Down a Hot Water Tank' in the article 'Shutting Down an Electric Water Heater' for information on lowering the water temperature in the tank.

How do I adjust the water temperature?

The electric water heater thermostats have a dial on them that you use to adjust the water temperature. The article on 'How To Adjust a Water Heater Thermostat', discusses this topic in detail. Do Not raise the water temperature to generate more hot water. The factory settings will at a safe level. Raising the temperature can cause burns and scalds and should only be done using extreme caution.

If you have too little hot water, the temperature setting is not the problem. The thermostats themselves could be causing the trouble. See 'How To Test Electric Water Heater Thermostats' for more information. It could also be a bad heating element, see 'Electric Water Heater Element Testing' to learn how to check the elements.

Not sure what you problem might be? See the article, 'How To Troubleshoot Electric Water Heaters'.

How do I test a thermostat to see if it is working correctly?

You want to see the article on 'How To Test Electric Water Heater Thermostats' for information and the correct testing procedure.

How do I replace an electric water heater thermostat?

To replace a thermostat, you will need to remove the old one. The article 'Installing a Water Heater Thermostat' Will provide you with instructions on removing the old one and installing the new one.

Where can I purchase a new water heater thermostat? How much do they cost?

Another challenge you will face is obtaining a new thermostat. The section on 'Purchasing a Water Heater Thermostat' in the article 'Installing a Water Heater Thermostat' will you some guidelines on how to obtain one.

How do I find out if my water heater elements are bad?

Another closely part is the heating elements. If the thermostats are working properly and you still don't have hot water, one or both of the elements could be bad.

See the article on 'Electric Water Heater Element Testing' for information and procedures to follow.

Summary

There are basically two reasons for being concerned with an electric water heater thermostat. The first and easiest is to adjust the temperature. Unless you have some unusual circumstances this is not needed most of the time.

The other more common problem is that one or both of the thermostats is malfunctioning. Hopefully this informatin pointed you in the right direction for a solution.