How To Replace Lower Thermostat On Electric Water Heater?

How To Replace A Water Heater Thermostat

Please keep in mind that this content may contain affiliate links. This means that, at no additional cost to you, we may gain a small profit on purchases made via our links. When changing one thermostat, it’s a good idea to go ahead and replace both the higher and lower thermostats as well as the thermostat in the middle.

Testing the Thermostats on a Dual Element Water Heater

Because the majority of electric water heaters employ both an upper and a bottom element, the procedure outlined below is intended for these models only. A multimeter and a screwdriver will be required for this test. It is possible to get an excellent, affordable multimeter either online or at your local hardware shop. Putting the UPPER thermostat through its paces:

  1. Immediately turn off the water heater’s electricity.
  2. Remove the panels that provide access to the elements, as well as the insulation beneath them
  3. Make use of a screwdriver to raise the top thermostat to its maximum position.
  4. Reduce the temperature of the bottom thermostat to its smallest level.
  5. Restart the water heater by turning the power back on.
  6. The two wires above and next to the reset button should be checked to ensure that electricity is being supplied to the water heater. The voltage should be shown as 240 volts.
  7. Check the power on the upper element terminal screws with your multimeter to ensure they are not faulty. If there is no power, the thermostat is defective and must be replaced. Ensure that the lower thermostat is operational if there is electricity.

Putting the LOWER thermostat through its paces:

  1. Reduce the temperature of the top thermostat to its lowest setting
  2. Increase the temperature of the bottom thermostat to its maximum setting
  3. Check to see whether there is voltage on the bottom component. In case the multimeter indicates that the element is powered, let a few minutes to pass before using the water to heat it. Turn down the thermostat’s temperature setting and listen for an audible click, which shows that the thermostat is operating properly.
  • Whether there is no voltage at the element, check to see if there is power at the lower thermostat. In order to test the top contact screw, place one of the multimeter probes there and another probe on the metal shell of the water tank. It should display a voltage measurement of about 120 volts.
  • The top thermostat, which supplies voltage to the lower thermostat, will need to be replaced if there is no indication of operation.
  • Place one probe on the lower contact screw of the water tank and the second probe on the metal casing of the water tank if a reading is obtained. It should display around 120 volts. If this is not the case, the lower thermostat will have to be changed.

Electric Water Heater Thermostat Replacement

Step 1

Before working on a water heater, make sure the electricity is turned off or the breaker is turned off.You will need to remove the access panel and the safety cover in order to change the thermostats (do this for both upper and lower access panels on dual element units).Make sure the power is turned off with a voltage meter for the sake of safety before proceeding.Make a basic schematic of how the wires are linked to the diagram and label it accordingly.

Remove the wires from the thermostat and set them aside.

Step 2

In order for the thermostat to sense the internal water temperature, it must be secured in place by means of a particular bracket that clamps down on it tightly against the tank wall.Remove one side of the bracket by gently prying it out while twisting the other side of the thermostat upwards to prevent the bracket from locking back into place.Repeat the process on the opposite side.On dual element versions, repeat the process with the lower thermostat.

Step 3

To purchase a replacement thermostat, bring the old thermostat(s) with you. Despite the fact that most thermostats are interchangeable, the greatest results are obtained by precisely matching the parts.

Step 4

If the bracket was broken during the removal of the thermostat, you can purchase a replacement bracket at the same time. When the old bracket is removed, the new one should be placed flat against the tank and dragged downward until it is securely in place.

Step 5

Replacement brackets are available if the bracket was destroyed during the thermostat removal process. The old bracket can be wrenched upward to remove it, and the new one may be put flat against the tank and slid downward until it is securely in place.

Gas Water Heater Thermostat Replacement

Gas water heaters employ a different sort of thermostat system than electric water heaters.Generally speaking, on gas water heaters, the gas control valve, which incorporates both an adjustable thermostat and a heat limiting mechanism, is positioned on the outside of the unit, near the bottom.It may be distinguished from other components by the fact that it has temperature and pilot light controls.If the thermostat on a gas water heater malfunctions, you will need to replace the gas control valve component that controls the gas flow.

Is it necessary to replace a water heater thermocouple or an electric water heater element?Take a look at our articles on the subject!

Electric Water Heater Thermostat Replacement Tips

Detailed instructions for replacing the thermostat on an electric water heater. Learn about how it works, the complications that might arise as a result of a thermostat failure, and how to avoid some of the problems.


  • What it is and how it works
  • What to do when the temperature is too high
  • How to change a thermostat
  • Consequences of doing so

How does a thermostat work

Every electric water heater is fitted with one or two thermostats, which are used to regulate and control the temperature of the water as well as turn on and off the heating element.Upper and lower thermostats regulate the temperature of the upper and lower heating components, respectively.Some testing must be done to establish which thermostat is malfunctioning in order to ascertain if the electric water heater is not producing any hot water or if the temperature is not as required (set).Furthermore, the thermostats will allow one heater to run in a simultaneous mode, so that both heaters heat water at the same time, or in a non-simultaneous mode, so that both heaters heat water at the same time.

Thermal controls for water heaters are surface mounted and firmly fastened to the tank’s side wall by a screw.Any sloppiness will have an impact on the usual operation.These are used to detect heat transfer through the tank surface and regulate the temperature of the tank.The ECO or high limit switch (if applicable) is a component of the thermostat that protects the machine and its users from excessively high temperatures.

How to change the temperature on the thermostat

  • As a safety measure, the hot water temperature within the storage tank is factory fixed at 120 degrees Fahrenheit
  • however, you may simply adjust the output temperature by turning a dial. If you raise the temperature setting over the factory preset temperature, there is a risk of scorching injuries, and it may not be cost-effective to heat the room. Burns or significant damage can occur in as little as 5 seconds if the temperature is set at 120 degrees Fahrenheit
  • injuries can occur in less than 5 seconds at 140 degrees Fahrenheit
  • and injuries can occur at 160 degrees Fahrenheit in less than half a second at 160 degrees. Make sure that the electrical supply to the water heater is switched off before you make any adjustments to the thermostat setting on the water heater.
  • Remove the lid once the power has been turned off to have full access to the thermostat
  • Using the screwdriver, turn the temperature adjustment dial clockwise until the required temperature is reached.
  • Return the lid to its original position and switch on the power

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How to replace an electric water heater thermostat (video included)

  • The technique for changing a water heater thermostat is the same whether the element is on the bottom or top side. Replace a thermostat only after the electrical power to the device and breaker have been switched off.
  • To gain access to the thermostat, remove the lid and insulation from the unit. Remove the protective plastic cover
  • Using the voltmeter, check to see that there is no electrical current flowing through the heater.
  • Disconnect the cables that are connected to the thermostat. Make sure they are clearly identified so that you don’t have to guess what they are when you rejoin
  • Removing the thermostat from its mounting bracket is a good idea.
  • To clean the tank surface, use a firm brush to remove the scale and dirt.
  • Install a new and identical element, making sure that the rear of the element is flush with the tank’s top surface. Please keep in mind that faulty installation will result in erroneous operation of the water heating system.
  • To reconnect the wires, refer to the wiring schematic that is printed on the lid.
  • Restore the lid and insulation to their original positions and restart the power
  • Set the thermostat to the appropriate temperature and turn on the heater for a few minutes to test it.

Electric water heaters are often fitted with two thermostats, one at the bottom and one at the top.The top one has a high limit that is not adjustable, and if it trips, you must manually reset it to prevent it from happening again.If the temperature of the hot water inside the heater rises to an excessively high level, the high limit switch is activated.This terminates the heating process, necessitating a manual reset of the heater.

Problems when the thermostat is not working properly

  • If the temperature is adjusted too low, there will be insufficient or no hot water stored in the tank.
  • It is possible that the outgoing water will be excessively hot if the temperature is set too high.
  • Water that is overheated and the need for continuous operation are the consequence of a thermostat that has been put incorrectly and is not in touch with the tank.

When deciding where to install the electric water heater, it is important to provide enough space between the thermostat and the surrounding parts so that the thermostat can be readily used to modify the temperature, changed if it becomes damaged, and cleaned as part of routine maintenance.Precautions should be taken When the electricity is turned on, avoid working on the thermostat or water heater.As a rule, make sure the breaker is in the OFF position at all times.It is essential that you consult with a professional to ensure that your thermostat is properly replaced.


As previously said, this book is intended for homeowners who are capable of doing their own home improvement projects. The book includes some helpful hints that will assist you in learning how to replace an electric water heater thermostat, as well as identifying and resolving issues that might interfere with the correct heating of the water.

How to replace an electric water heater thermostat

An electric water heater thermostat replacement is explained in detail in this do-it-yourself repair tutorial.The thermostat regulates the temperature of the water by turning on and off the heating element on and off.If the thermostat stops operating, the element will either not turn on at all, resulting in cold water, or it will stay on for an excessive amount of time, resulting in scorching water.Replace a faulty thermostat with a replacement part that has been approved by the manufacturer.

Replace the thermostat in an electric water heater made by Kenmore, State, A.O.Smith, Rheem, Whirlpool, or Reliance by following the instructions outlined below.How to replace the thermostat on an electric water heater with this video repair instruction.Replace a water heater’s theromstat using this video tutorial.Warning: It might be dangerous to do repairs or maintenance on appliances or power equipment without proper training.

If you decide to do repairs or maintenance on your own, you are taking the risk of injury to yourself or your property.In an effort to decrease the danger, make use of the right tools and safety equipment as specified in the applicable handbook and adhere to all of the guidelines.Wait until you are certain that you understand all of the instructions and are capable of finishing the repair before moving further.A qualified technician, on the other hand, should be called in for some repairs or maintenance.

How to Test an Electric Hot Water Heater Thermostat

  • There are two thermostats in an electric water heater, both of which are situated beneath access panels on the side of the tank. An electric hot water heater includes two thermostats, each of which controls two distinct heating elements — one in the top half of the tank and one in the bottom half — that are located in the tank. Typically, when the higher thermostat fails, you will have no hot water at all, but a failed lower thermostat will manifest itself by providing only a limited amount of hot water before the tap water becomes cold. Though not a rigid guideline, it is preferable to test the thermostats to discover which one is in need of replacement before making any decisions. Tests on the thermostats are carried out using a multimeter, which is a standard electrician’s equipment. Once you’ve discovered which thermostat is malfunctioning, you may replace it and get your hot water heater back up and running. A Phillips screwdriver, a flat-head screwdriver, and a multimeter are all necessary tools.


Always turn off the electricity to any electrical equipment before trying any repairs on it.

Step 1

Identify and deactivate the water heater circuit breaker located within the main service panel.

Step 2

Using a Phillips screwdriver, remove the top and lower access panels from their frames. Electric hot water heater access panels are often located on the side of the unit and have an electrical warning placard affixed to them.

Step 3

Remove any insulation that may be covering the thermostat or the heating element by pulling it away. Keep an eye out for any wires that may be pulled while changing the insulation.

See also:  What Is The Life Expectancy Of An Electric Water Heater?

Step 4

To adjust the temperature setting on the top thermostat, use a flat-head screwdriver to turn the dial to the maximum setting. A multimeter’s scale should be set to the RX1 setting.

Step 5

Place one probe on the left screw terminal with the white wire and another probe on the terminal directly above the white wire on the screw terminal on the right side of the board. The reading on the multimeter should be zero. (See illustration) Any other value on the multimeter shows that the thermostat is not working properly.

Step 6

To do this, use the flat-head screwdriver to lower the top thermostat to its lowest setting.During this procedure, you should hear a clicking sound from the thermostat.One probe should be placed on the terminal above the white wire, and the second probe should be placed on the terminal to which the black wire is connected.In this case, the reading on the multimeter should be zero once more.

Step 7

Keep the higher thermostat on its lowest setting while you test the lower thermostat on its highest setting.Set the lower thermostat to the highest setting by using a screwdriver to turn it.Make a connection between each terminal on the bottom thermostat with one probe of the multimeter.There are just two connections on the bottom thermostat.

The multimeter should show a reading of zero when this occurs.

Step 8

Reinstall the defective thermostat, and then replace the insulation that was previously placed over the thermostats and heating components. Replace the access panel covers, locking them in place with the retaining screws that were previously installed. The electric water heater will be activated after the circuit breaker has been reset.

How to Test a Water Heater Thermostat and Replace it if Needed

Check the thermostat if your hot water isn’t hot enough, as instructed in the handbook.Do you, on the other hand, know how to test a water heater thermostat?And, if it turns out to be problematic, do you know how to repair the thermostat on your water heating system?All excellent questions, all of which will be addressed in this essay!

There are two possible explanations for why your electric water heater isn’t heating the water.Perhaps the heating element or the thermostat is not functioning properly.This article will walk you through the process of testing a water heater thermostat and, if required, replacing it with an appropriate replacement.It’s actually not as difficult as it appears!

Water Heater Thermostat Basics

The electric water heater thermostat is positioned on the front of the water heater tank, beneath an access panel that provides access to the tank.The thermostat is in charge of maintaining the temperature of the water in the tank.It does this by opening and closing connections in order to switch on and off the flow of electricity to the heating elements, which are immersed in the tank and are responsible for heating the water in the tank.There is a bi-metal switch that is flush with the wall of the water heater’s tank and operates the water heater.

With each degree Celsius that the water within the tank is raised, the steel tank becomes warmer, which in turn warms the bi-metal switch within the thermostat.The bi-metal switch on your water heater will open when the temperature of the thermostat reaches 120°F, preventing electricity from flowing to the heating element.If your water heater is set to the recommended 120°F, the temperature of the thermostat will automatically rise.When the temperature falls below the 120°F set point, the polar opposite occurs.The bi-metal switch is closed, and power is permitted to flow to the heating element through the breaker circuit.This video will demonstrate how the thermostat on your water heater operates.

Take a look at the video

Identifying Which Thermostat is Faulty

With a capacity of 30 gallons or more, the vast majority of water heaters employ two heating elements, each with its own thermostat.It is hooked into the thermostats so that only one heating element is activated at a time.The upper thermostat is responsible for bringing the top third of the water in the tank to the desired temperature.After that, it shuts off and switches the electricity to the lowest thermostat setting.

The two thermostats are not identical, and if one fails, the water heater will react in a different way than if the other fails.

How to Identify Which Thermostat Failed

  • Upper Thermostat (or Heating Element) Failure – If your upper thermostat (or heating element) fails, your water heater will cease to heat water completely. Because the top thermostat is in charge of the lower thermostat, if the upper thermostat fails, the lower thermostat will never turn on.
  • Theft of the Lower Thermostat (or Heating Element) – If your lower thermostat (or heating element) fails, you may either notice that the hot water is tepid or that the hot water runs out rapidly. Due to a broken lower thermostat, the higher thermostat will not be able to signal the heating element to turn on, resulting in the upper heating element heating just the top third of the water in the tank.

How to Test a Water Heater Thermostat

First and foremost, you must ensure that there is no discontinuity. You’ll need a Phillips and a flat head screwdriver, as well as a multimeter, to complete this task. Always switch off the electricity to your electric water heater before starting any work on it. Then double-check that the power has been turned off. Here’s how it’s done:

Shut Off the Power to Your Water Heater

  • At the main electrical panel, turn the breaker to the OFF position.
  • Remove the thermostat’s access cover and set it aside.
  • Removing the insulation and plastic protective cover is the first step.
  • Touch one of the multimeter’s probes to a grounded metal object (such as the tank casing, which is unpainted metal)
  • Connect the second probe to each thermostat terminal as well as the terminals of both heating elements.
  • At all times, the multimeter should display zero voltage (Zero).
  • To visually see how to switch off the electricity to your water heater, watch the video below.

How to Test a Water Heater Thermostat for Continuity

  • It’s time to check the thermostat on your water heater now that the electricity has been turned off at the main electrical panel. Step one is to check to see whether the reset button has been pressed. If this has happened, go ahead and reset it.
  • Remove the wires from the thermostat and set them aside. Pay close attention to how they are linked together.
  • A touch one of the multimeter is connected to the left side terminal through the reset button in step two
  • The other multimeter lead to the other terminal on the left side of the reset button should be touched as well.
  • If the thermostat has continuity, the multimeter should show a reading close to one hundred percent. This indicates that the thermostat is malfunctioning and must be changed
  • otherwise, it indicates that the thermostat is in good working order.
  • Rerun the test on the right-side terminals by pressing the reset button one again.
  • Step number three. Test the lower area of the thermostat by connecting one lead to the common terminal (located next to the temperature setting) and the other lead to the left heating element terminal
  • this will reveal whether the thermostat is functioning properly.
  • If the temperature of the water in the tank is lower than that set by the thermostat, the resistance reading on the multimeter should be near to 0 ohms.
  • Move the lower lead from the left heating element terminal to the right heating element terminal by pulling it up and out. The continuity indicator on the multimeter should indicate ″NO continuity.″
  • If the temperature of the water in the tank is higher than the temperature specified by the thermostat, you should see the exact opposite consequences
  • If the upper thermostat is functioning properly, you’ll need to check the lower thermostat as well.
  • The fourth step is to disconnect the power cables from the bottom thermostat.
  • Using the first lead, connect it to a single terminal and the second lead to the other terminal
  • It should be possible to measure resistance near to 0 ohms if the water temperature is below the thermostat’s set temperature
  • however, this is not always the case.
  • If the water temperature is higher than the thermostat’s set temperature setting, the multimeter should show no continuity
  • otherwise, the water temperature is too high.
  • A thermostat with the opposite reading indicates a defective thermostat.

Watch the Video

How to Buy New Water Heater Thermostats

Generally speaking, if you’ve decided that one of your water heater’s thermostats is malfunctioning and must be changed, it’s preferable to repair them both at the same time. Thermostats are available for purchase singly or as part of a set.

Buying a Tune-up Kit

Perhaps you might consider getting a tune-up package that contains both the top and lower thermostats, as well as two new heating elements, to simplify the process.It may cost a few dollars extra, but you’ll notice a significant improvement in the way your water heater functions in most circumstances.This is especially beneficial if your water heater has at least a few more years of useful life left in it.Tune-up Kit for Any Vehicle The ZERO EWH-01 Tune-up Kit is designed to work with the majority of electric water heaters.

A screw-in HWD heating element and an upper and lower non-simultaneous water heater thermostat are included with this package.An OEM tune-up kit for electric water heaters is also available from Rheem.You should replace your heating elements at the same time as your water heater if you wish to do so.Make sure the heating elements are the suitable size and type for your water heater.This article will guide you through the process of selecting the appropriate heating element.

Buying Upper or Lower Thermostats

Although it is usually a good idea to repair both thermostats at the same time, there are situations when it is just more convenient to replace only the malfunctioning one.This is especially true if you have plans to acquire a new water heater in the near future and are only attempting to get your present water heater up and running until you can make the purchase.Camco Thermostat, Upper Thermostat This upper thermostat from Camco offers a built-in reset button, changeable temperature settings, and a one-year guarantee on the mechanical components.If you choose, Rheem also makes an OEM upper thermostat for customers that desire it.

If you want a lower thermostat, the Camco 8123 is a decent low-cost choice, and Rheem, of course, also has one in this configuration.

Single Element Water Heaters

Although we’ve concentrated on double-element water heaters, certain models, particularly those with tanks of 20 gallons or less, may heat water with a single heating element.These water heaters are connected in a different way and require a single element thermostat to function properly.They may appear to be very similar to an upper dual element thermostat, however they have fewer wire terminals than an upper dual element thermostat.Camco Thermostat with a Single Element The Camco 07843 Single Element Thermostat is equipped with a built-in safety switch, changeable temperature settings, and a protective cover for further protection.

How to Replace a Water Heater Thermostat

Water heater thermostat replacement is a simple process that you should be able to complete on your own without any difficulties.Many homeowners, on the other hand, are more comfortable with the idea of employing a professional plumber to perform the work.You’ll need a Phillips and a flathead screwdriver, as well as a multimeter and your new thermostat to complete this project.Make certain that the thermostat you select is compatible with your water heater.

Shut Off the Power to Your Water Heater

  • At the main electrical panel, turn the breaker to the OFF position.
  • Remove the thermostat’s access cover and set it aside.
  • Removing the insulation and plastic protective cover is the first step.
  • Touch one of the multimeter’s probes to a grounded metal object (such as the tank casing, which is unpainted metal)
  • Connect the second probe to each thermostat terminal as well as the terminals of both heating elements.
  • At all times, the multimeter should display zero voltage (Zero).
  • Step one is to unplug the thermostat wires from the wall. Pay attention to how they’ll be reconnected
  • this is important.
  • To remove the thermostat from the retaining bracket, carefully lift it out.
  • Step two is to swap out the old thermostat for a new model. Check to see that it is the proper thermostat for your heater.
  • Check to see that the rear of the thermostat is snugly pressed against the tank’s inside.
  • The cables to the thermostat should be reconnected.
  • Replace the protective cover with a new one.
  • Measurement Step ThreeCheck and change the temperature setting to 120 degrees Fahrenheit
  • Remove the insulation and access cover and replace them.
  • Activate the water heater’s power supply

Watch the Video

Common Questions

Some frequently asked questions about water heater thermostats have been included below for your convenience:

Are Electric Water Heater Thermostats Universal?

No.Some water heaters employ two heating elements, while others only use a single heating element to heat the water.These are not the same, so you’ll want to make sure you get the right one for your water heater before buying it.Aside from that, in dual-element water heaters, the lower and top thermostats are not the same and cannot be used in combination.Because the top thermostat is bigger and contains more terminals than the lower thermostat, it is preferred.

As a recommended practice, always check the information tag on your water heater to ensure that you are purchasing the suitable thermostat for your system.Despite the fact that there are dozens of household electric water heater manufacturers, and the majority of them can use OEM components, investing a few more minutes up front may save you time, money, and headache down the road.

How to Reset a Water Heater Thermostat?

If your thermostat has tripped, you can remove the insulation from the tank by opening the access cover on the front of the tank. On the thermostat, there should be a red button to press. To reset the device, simply press it in. If it trips again, you may be dealing with a more significant issue (see below).

See also:  How To Remove Water Filter From Whirlpool Refrigerator

What Causes a Thermostat to Trip?

There are a variety of reasons why a thermostat may malfunction. A defective thermostat or heating element are the most typical causes, but it can also be caused by a poor electrical connection or even a malfunctioning reset button. If you are having trouble determining the source of the problem, you should consult with a professional plumber.

How water heater thermostats works

More detail: Electric water heater A bi-metal switch is two different metals sandwiched together. Metal expands when heated, except one metal expands differently than other metal, causing a deformation or bend. Inside electric water heater thermostat, the bending metal opens and closes a mechanical switch. Typical household non-simultaneous water heater has 2 heating elements called upper and lower elements. Elements are controlled by upper and lower thermostats. Each element is connected to a thermostat. Thermostats read temperature through side of tank wall and turn elements ON and OFF. Residential water heater thermostats can be manually set to temperatures between 90�F to 150�F. Commercial water heater thermostats  120-180�F. How to adjust thermostats How to replace thermostat on electric water heater Higher thermostat settings use more electricity. Both elements on ordinary residential water heater are never ON at same time unless specific wiring is changed. How to wire thermostats Upper thermostat is main controller. Upper thermostat turns on upper element until top 2/3 of tank reaches temperature setting. After top of tank is heated, upper thermostat turns-off upper element and sends power to lower thermostat which turns on lower element. Lower element runs until tank reaches temperature setting. Lower element turns on-and-off during standby hours to keep tank temperature at thermostat set point. See LargerSome thermostats, the L2 and T1 screws are empty slot or rivet since wires do not connect to either L2 or T1. Brands of thermostat vary slightly, screws are located differently, some numbers are slightly different, but basic concept is same from brand to brand. Water heater manuals available on-line. Label on side of tank shows watts and volts of appliance. Each thermostat comes with instruction sheet. When replacing thermostat, take digital photo of water heater and old thermostat to hardware store or plumbing store for quick identification. Thermostat must sit flat against tank wall so temperature reading is accurate and water heater is protected from overheating More detail: Electric water heater thermostat operation sequence Residential water heaters can be wired 4 basic ways. Non-simultaneous found in most residential water heaters. Plus simultaneous, redundant, and off-peak. The key is knowing how a thermostat works. How to wire thermostats Diagram on left illustrates basic non-simultaneous thermostat function. This thermostat is found on 240 Volt water heaters that have 2 elements. Check label on side of tank for voltage info. Figure volts, amps, watts Power from breaker box connects to L1 and L3 screws > some thermostats, the screws are marked simply 1 and 3. Top half of thermostat is the ECO or energy cut off > The ECO is heat sensitive, so if temperature reaches dangerously high 150-180�F, then ECO trips and water heater no longer has power. This prevents water heater explosion. Viewing the diagram, power from L1 and L3 pass through ECO red reset and go to L2 and L4 screws. After power passes through ECO, it is available for heating water. To control heating, power arrives at the thermostat which begins at T1 screw. Inside the thermostat a bi-metal switch. Two different metals are fused together. Each metal expands differently when heat is applied. Since the two metals are joined, the metal that expands most causes the bi-metal switch to bend. The bending action opens and closes the switch. In the diagram, the bi-metal switch is connected to T1. When temperature inside tank is cool, the bi-metal switch rests against T2 so power travels from T1 to T2, and then on to the upper heating element. When temperature inside tank is hot, the bi-metal switch disengages from T2 and clicks over to T4. When this happens, T1 sends power to T4, so the upper heating element is turned off and power travels to lower element and thermostat through the T4 screw. In a 240 Volt water heater, elements must receive power from 2 hot leads. The diagram shows the hot leads at L1 and L3 screws. In the description above, power from one hot lead was switched between T2 and T4. From there, power traveled to the elements but the circuit was not yet complete. To complete the 240 circuit, each element must connect back to the L4 screw.  See complete circuit diagram below.

How to Set How Water Heater Temperature by Thermostat

You might be wondering how to adjust the temperature of your hot water heater. In this section, you will learn all you need to know about your gas or electric water heater thermostat, including how to adjust your hot water heater temperature thermostat and what temperature is optimum for hot water.

What’s the Right Temperature for a Hot Water Heater?

It’s an often asked question: what is the optimal temperature for hot water?Setting a tank-based hot water heater to 120 degrees Fahrenheit is recommended by the United States Department of Energy.If you have never changed the temperature of your hot water heater, it is most likely set to the 140-degree Fahrenheit level that is recommended by most manufacturers of hot water heaters.What is the significance of adhering to this temperature standard?If the water heater thermostat setting is set to an excessively high temperature, the water will be too hot and might cause burning or scorching.

If it is set too low, germs may be able to flourish, leading to the spread of water-borne illnesses.

How to Set Your Hot Water Heater Temperature Thermostat Setting

Before you make any modifications to the temperature thermostat setting on your hot water heater, you should first ascertain what the current temperature is set at so that you can establish how much you need to alter the settings.A conventional cooking thermometer may be used to quickly and accurately detect the temperature.You should calibrate your thermometer once you have determined the current temperature setting.Fill a cup halfway with cold water and submerge your thermometer until the temperature dial reaches 32 degrees, or the lowest temperature displayed on your thermometer’s gauge, and then remove it.By calibrating the thermometer, you are effectively resetting it so that you will be able to acquire an accurate temperature measurement in future.

Meanwhile, locate the faucet that is closest to the water heater and turn it on until it is hot (while you are calibrating your thermometer).Precautions must be taken!If your thermostat is set too high, the temperature may be high enough to burn you.Once the water is hot, fill a cup halfway with it and take the temperature with a thermometer by inserting it in the water.

Adjusting a Gas Hot Water Heater Temperature Thermostat Setting

The majority of gas water heaters are straightforward due to the presence of a clearly readable dial at the bottom of the tank’s bottom section. If you follow the methods outlined below, it is simple and straightforward to alter this dial.

  1. First, adjust the temperature by turning the knob to the hotter or cooler position, depending on the situation.
  2. After that, let it sit for a few hours (around three or four) and then check the temperature again.
  3. If the temperature is still incorrect, make another adjustment and repeat the process until the problem is resolved. Do you require assistance? Give Hackler Plumbing a call if you want the services of a McKinney plumber, and we will be happy to assist you

Adjusting an Electric Hot Water Heater Temperature Thermostat Setting

The process of adjusting the temperature thermostat setting on an electric hot water heater is a little more difficult, but still pretty simple.The vast majority of electric water heaters are equipped with two thermostats: an upper and a lower thermostat, both of which are placed beneath two control panels.Setting both thermostats to the same temperature can help to guarantee that your electric water heater operates as effectively as possible.One thing to keep in mind is that some tiny electric hot water heaters only have one thermostat.

Here’s how to adjust the temperature on your electric hot water heater thermostat:

Please keep in mind that you will want a screwdriver to execute the following procedures in order to alter the temperature of your water heater.

  1. Make sure your water heater is off by turning off the electricity. This may be accomplished by locating your circuit breaker and shutting off the electricity in the area surrounding your water heater
  2. Then, locate the thermostat(s) on your water heater and turn them on. Typically, they are located behind a control panel that is secured with screws. Remove the cover from the access panel using your screwdriver (s). To access the thermostat, you may need to remove the insulation from your heater if it is properly insulated. The thermostats will be controlled by a dial, and the dials will have a varying reading depending on the manufacturer of the heater.
  3. Once the control panel has been removed, you may change the temperature knobs to make the room hotter or colder according on your preferences in terms of temperature. Take care to set both thermostats to the same temperature setting if you have more than one.
  4. Replace the control panel covers and the screws with your screwdriver after they have been removed. After that, re-energize your water heater’s electrical system.
  5. After a few hours, check the temperature of your hot water again (about three to four). Continue to follow the above instructions until the water temperature reaches the required setting
  6. if it still does not, repeat them until the temperature reaches the ideal setting for your needs.

Other Considerations: Water Heater Thermostat Setting Safety

There is one thing you should be aware of: your water heater is fitted with something known as a temperature and pressure relief valve, sometimes known as a ″T&P valve.″ These can become worn out over time, and one sign that they should be replaced is the presence of water leaking through.This is a very crucial safety feature.In the event that your unit is outdated or if your hot water heater pressure relief valve leaks after being replaced, get it examined by a competent plumber.

Test & Replace a Water Heater Thermostat: DIY Guide

We shall almost certainly all be confronted with the situation of a water heater that is not producing any hot water at some point in our lives. We have two options: either contact a qualified plumber or do it ourselves. Fortunately, most water heaters can be repaired reasonably quickly and inexpensively. There are two primary reasons for a water heater not working:

  1. the heating elements
  2. the thermostats.

If you’ve never tested or replaced a water heater thermostat before, the task may appear to be too difficult to complete.It’s not too difficult.Fortunately, if you have someone who knows what they’re doing to guide you through the procedure and a few basic tools, the process is pretty simple.When bathing or cleaning, no one enjoys using cold water.If you are experiencing no hot water, we will need to check the water heater thermostat and replace it if necessary.

In this post, we’ll look at how to diagnose your electric water heater thermostat and, if necessary, how to replace it.

How Electric Water Heater Thermostats Work

When you begin to realize that your water heater isn’t operating as efficiently as it should, the thermostat is more than likely the source of the problem, or at the very least a contributing factor.No need to repair the entire electric heater when you can save yourself both time and money by just replacing the thermostat instead.Once you’ve gone over the following instructions, it will only take a few minutes……………………..Electric water heater thermostats function by opening and shutting connections, which allow electricity to pass to the heating components of the water heater.The heating components are activated and deactivated in response to demand.

All current domestic water heaters are equipped with two heating elements as well as two temperature controllers.On the side of your electric water heater, there are two panels that contain a thermostat and a heating element, one for each panel.The higher thermostat differs from the lower thermostat in several ways.The higher thermostat is bigger than the lower thermostat, and it regulates the lower thermostat.

  1. It is quite rare for both thermostats to fail at the same time (although I do recommend replacing both when one fails).
  2. When an upper heating element or thermostat fails, the water heater’s ability to provide hot water is compromised.
  3. Whenever a lower heating element or thermostat fails, the top thermostat and heating element will take over and continue to heat water in the upper part of the hot water storage tank.
  4. Despite this, you will observe that the hot water runs out quickly or is barely lukewarm.

Are Electric Water Heater Thermostats Universal?

No, not all water heater thermostats are designed to be interchangeable.It is important to note that there are certain differences in thermostats between single-element and dual-element water heaters.Additionally, with dual-element water heaters, there is a differential between the top and bottom thermostats.In order to properly select a water heater thermostat, you must first determine the number of elements and the voltage of the water heater in question.It is possible to obtain this information from the data tag located on the side of the water heater.

If the data tag is not there, you may tell the difference between a single-element and a dual-element water heater by counting the number of access panels on the water heater.The voltage is inscribed on the end of the heating element, and it may be read with a magnifying glass.240 volts is the standard voltage for residential dual-element water heaters.There are more than 50 different household tank-style electric water heaters available on the market, and the thermostats on the majority of them are designed to be interchangeable.

  1. When making a purchase, it is important to thoroughly read the product description.
See also:  What Size Wire For Hot Water Heater

Dual-Element Thermostats

Typical household water heater thermostats are seen in this photo, which includes an upper and lower thermostat for each.Because it is located above the lower thermostat, the thermostat on the left has a high limit switch, which can be identified by the red reset button.The upper thermostat is in charge of controlling both the upper element and the lower thermostat, respectively.When you look at it from this angle, you can see the bottom thermostat, which regulates the lower element.For a replacement kit that includes two heating elements, upper and lower thermostats, and seals, we recommend the Rheem SP20060 Electric Water Heater Tune-Up Kit, which can be purchased on for about $30.

Consider the Rheem UV11698 UV11698-Thermostat-Electric if you simply want to purchase the top thermostat.A universal upper thermostat produced by Rheem is what it is.You may get a lesser thermostat, such as the Rheem SP11695 Electric Thermostat, if you just require one.It’s a Rheem lower thermostat that’s universally compatible with other brands.

Single-Element Thermostats

  • The thermostat seen here is for a water heater with a single heating element. The thermostat is very similar to an upper dual-element thermostat, with the only variation being the amount of wire terminals on the thermostat. In this case, the single element thermostat has just two terminals on the right side and four on the left side, as you can see in the illustration. A single-element thermostat, such as the Camco 07843 Single Element Water Heater Thermostat with HLC, is available for purchase if you require one. This is a single-element thermostat with a built-in high limit switch that is universally applicable. The following is a list of the supplies you’ll require: In addition, you’ll need a 1/4-inch nut driver or a flathead screwdriver, two Phillips screwdrivers, an analog or digital multimeter/voltmeter, and a new thermostat.

How to Test a Water Heater Thermostat for Continuity – Step-By-Step

We must examine the thermostats for continuity in order to identify whether or not the thermostat has failed.You’ll need an analog or digital multimeter for this, which you can get here.WARNING: Working with electricity is extremely hazardous and can result in death.Before dealing with wiring or electrical connections, be certain that the power is turned off.Follow these procedures to determine which thermostat is malfunctioning.

Step 1: Turn the power off

Make your go to your circuit board and locate the water heater breaker to switch off the power supply. Discover and switch off the breaker that is labeled ″water heater″ or ″hot water″ in the electrical panel box where the water heater is located.

Step 2: Remove the outside access covers

To remove the access cover from the upper and lower thermostats, use a 1/4-inch nut driver or flathead screwdriver to pry them off. Fold the insulation back over the thermostat to prevent it from being damaged. To keep the insulation out of the way, use tape to hold it in place. Remove the plastic cover that covers the thermostat on the inside of the house.

Step 3: Confirm power is off to the water heater

Make sure the water heater is not receiving electricity before working on it with a multimeter before doing anything on the thermostat.If you have a voltage stick, you may also use it to measure the voltage.Connect the top and legs of the multimeter at the same time, using the multimeter connectors.The meter should be set to zero.Touch each leg of the water heater while the black connector is in contact with it to ensure there is no electricity.

Step 4: Check the high limit reset button

  • If the manual reset switch, also known as the high limit reset button, has been tripped, it should be replaced. This button may trip if one or more of the following conditions exists: the thermostat contacts have fused closed
  • the thermostat contacts have fused open
  • the thermostat contacts have fused closed
  • the thermostat contacts have fused open
  • the thermostat contacts have fused closed
  • the thermostat contacts have fused closed
  • the thermostat contacts have fused closed
  • the thermostat contacts have fused closed
  • the thermostat contacts have fused closed
  • the thermostat contacts have fused closed
  • the thermostat contacts have fused closed
  • the thermostat contacts have fused closed
  • the thermostat
  • The thermostat is not in proper working order.
  • The heating element has stopped working

Step 5: Disconnect the wiring

Take a photo with your phone or a digital camera to use as a reference if it becomes necessary to identify which cables are connected to which terminal in the future. To detach the wiring from the thermostat terminals, unscrew the terminal screws using a Phillips #2 screwdriver and pull the wiring away from the terminals.

Step 6: Check the thermostat with a multimeter

Set the resistance of the multimeter to the lowest ohms possible (typically x10).Using your fingers, squeeze the probes together and adjust the needle to zero to calibrate your meter.To check the resistance of a digital multimeter, set it to the lowest possible value of resistance (usually 200), or, if your multimeter has an option for resistance with tone, choose it.Take one of the black probes from your multimeter and insert it into the screw terminal on the left side of the instrument.Take the red probe and connect it to the other left-side terminal on the other side.

Ideally, the meter should read close to zero if the terminal is in good working order.This means that the thermostat is not functioning properly and must be replaced.This procedure should be repeated for the right-side terminals and the element terminals.For a demonstration, please see the video above.

  1. You will need to repeat these procedures for the lower thermostat and element if the higher thermostat and element are working properly.
  2. As soon as you have finished testing your water heater thermostat, you may either reconnect the wire and close the access cover, or you can proceed to the next step, which is replacing the thermostat.
  3. Assuming you have decided that your thermostats do not require replacement, you may proceed to inspect your heating components.
  4. To do so, please see our How to Test and Replace a Bad Water Heating Element page, which includes step-by-step instructions.

How to Replace a Faulty Water Heater Thermostat – Step-By-Step

Once you’ve discovered which thermostat is faulty, it’s time to begin the process of removing and replacing it.A word of caution: As previously said, it is typically recommended to change both thermostats and heating components on a regular basis.The reason for this is that if one of the heating components is beginning to fail, it has the potential to short out the replacement thermostat shortly after it has been placed, causing it to fail.Some of the stages will be repeated in this section.Assuming you performed the testing procedures outlined above, you may be able to skip to Step 5.

For those who have not yet tested their thermostats, we will first go through the preparatory processes.We’re going to start from the beginning.

Step 1: Turn the power off

Take a trip over to the circuit breaker box and look for the switch labeled ″Water Heater″ or anything along those lines. It should be turned off, making sure to turn off both switches if it is a 220v switch. If you’re not sure which water heater is causing the problem because of outdated stickers or labels, get a professional to turn them off for you.

Step 2: Remove the outside access covers

Remove the cover panel that corresponds to the thermostat that has to be replaced and set the cover panel aside.The coverings for water heater tanks are often located on the side of the tank.Ensure that you do not loose any of the little screws by using the 1/4-inch nut driver or a flathead screwdriver for this section.Remove the insulation from the thermostat as well as the plastic protective cover that covers it.

Step 3: Confirm power is off to the water heater

Each wire should be tested with your multimeter/voltmeter.This may be accomplished by grounding one of the lines and checking each terminal one at a time until the problem is resolved.While you may have shut off the electricity at the breaker, you should always double-check your work using one of these meters to ensure that you haven’t accidentally caused an electrical shock.Connect the top and legs of the multimeter at the same time, using the multimeter connectors.The meter should read 0 at this point.

Touch each leg of the water heater while the black connector is in contact with it to ensure there is no electricity.

Step 4: Disconnect the wiring

Take a photo with your phone or a digital camera to use as a reference if it becomes necessary to identify which cables are connected to which terminal in the future. Disconnect the wiring from each terminal on the thermostat with a Phillips screwdriver #2. Remove the thermostat from the wall.

Step 5: Remove the defective thermostat

Gently remove the old thermostat by pulling outward on the clips and raising the thermostat up and out of the retaining bracket with your finger or a flathead screwdriver. Caution should be exercised to avoid breaking the retainer bracket. It is possible that breaking this retaining clip will result in the need to replace your water heater.

Step 6: Insert the new thermostat

Inserting the new thermostat into the retaining bracket that holds the old thermostat in place will allow you to precisely position the new thermostat.Reconnect the wires to the relevant terminals by twisting them together.If necessary, you can refer to the photograph you took previously for guidance.Check to see that each wire is securely linked to the next.Check to see that the thermostat is securely attached to the water heater, otherwise the thermostat may not operate correctly.

After that, adjust the thermostat to the temperature you like for the water.We recommend that you use water that is no hotter than 120 degrees Fahrenheit.These modifications may be accomplished with the use of a flathead screwdriver.Using this temperature level is critical since anything greater than this can present an immediate scorching risk for youngsters and the elderly.

  1. Tips from the experts: If you intend to replace your heating element with a new thermostat, you must first empty your water heater.
  2. Some people propose doing a quick change without draining the storage tank; however, I do not encourage this because any mistakes might cause harm to the interior of your house.
  3. Draining your water heater, as well as other maintenance suggestions, may be found in our post Water Heater Maintenance Tips for Gas and Electric Tank Water Heaters.

Step 7: Reattach the cover panels

Now that you’ve completed the replacement, it’s time to seal everything up and double-check your work for mistakes. Remove the plastic protective cover and insulation and replace them with new ones. Reattach the outside access panels if they have been removed.

Step 8: Turn the power back on

Following the completion of the installation, return to the electrical box and re-energize the circuit breaker (if necessary). Hot water recovery will take roughly one hour to complete, but you should be able to start using hot water within 15 minutes after turning on the faucet. Over the next several days, make sure to check on the water heater on a regular basis.

Water Heater Thermostat FAQs

What should water heater thermostats be set at?

Electric water heater thermostats are typically pre-set by the manufacturer to 110 or 120 degrees Fahrenheit, depending on the model.You have the option of increasing the temperature to the maximum setting, which is typically 150 degrees Fahrenheit, if necessary (65 degrees Celsius).The maximum water temperature setting should be no greater than 120 degrees Fahrenheit (48 degrees Celsius), since a higher setting might provide a scorching threat to small children and the elderly.

Should water heater thermostats be set to the same temperature? 

In fact, the top and lower thermostats should both be set at the same temperature. The dip tube is responsible for delivering cold water to the bottom of the tank. Having consistent settings across the tank helps to keep the temperature consistent throughout the tank.

What would cause a water heater thermostat to burn up?

A malfunctioning heating element, a power surge, or just the passage of time can cause a water heater thermostat to burn up.When internal components of water heater thermostats wear out, they become faulty and fail.Even with regular electric currents, an older thermostat may experience failure.If the manual reset switch on your water heater thermostat does not work, the thermostat will need to be repaired or replaced.Replacement of both thermostats and heating elements should be done at the same time because if one of the heating elements is beginning to fail, it may cause the new thermostat to short out shortly after it is installed, which is not recommended.

Final Thoughts

Simply said, that’s the whole story!Water heaters aren’t too difficult to maintain, and replacing a thermostat can be completed in a matter of minutes if you know what you’re doing and have the right tools.The most important thing to remember while working with electrical equipment is to avoid taking shortcuts.Although it is possible to change your water heater thermostat in a short period of time utilizing the correct skills and tools, doing so is not recommended.DISCLAIMER: The information provided on is not intended to be professional guidance.

Before beginning any job, you should contact with a competent expert and verify that all necessary permits have been obtained.It is owned and operated by Hubert Miles who is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by placing advertisements and links on their websites that direct traffic to (hereinafter referred to as ″″ or ″ Associates Program″).As an affiliate, participates in a variety of affiliate programs with other websites.Hubert Miles receives a commission for recommending visitors and commerce to these businesses.

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