Maintenance Thermostat

How to test electric water heater thermostat with digital multimeter

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A faulty water heater thermostat is an inconvenience to you, your family, or your business. Although there are different types of failures, a malfunctioning electrical system is a common problem. The point of failure may vary and could be faulty wiring or loose connections, a bad heating element, or a water heater thermostat.

A failure in the thermostat, heating element, or both could lead to completely cold water. Or partly warm water that does not reach the set temperature.

If your water heater stops providing you with hot water according to your settings and requirements, you can test the element and thermostat to ensure they are functioning properly. 

Thermostat role in water heaters

The main work of a thermostat in a heater is to regulate and maintain the water temperature, hence ensure safety and optimize energy use. When it starts malfunctioning, it cannot control the water temperature to suit your requirements. 

In practice, the thermostat controls the heating elements to maintain the water at the set temperature. When the water is cold, the thermostat automatically powers the elements to heat the water to the desired temperature. Upon reaching the set temperature, the thermostat shuts off the element, until the water gets colder again. As such, its work is to ensure the water temperature remains constant at a certain set level. Consequently, it reduces the risks of heating the water to very high and unnecessary temperatures, hence reducing the energy use without compromising comfort.

water heater thermostat

Types of water heater thermostat failures and impact

A faulty thermostat may not provide any control, or may only function partially and could result in your water not reaching the usual hotness levels.

Potential faults include;

  • A completely open thermostat that does not power the element at all.
  • A partial open thermostat – heats the water partially such that the temperature does not reach the desired level.
  • A short circuit- In this case, the thermostat does not provide any control and will continuously heat the water. Most often, a shorted thermostat results in the tripping of the heater reset button or high limit switch. 

Most standard water heaters have two thermostats, an upper one and a lower one. If one of these fails, it impacts the water heating process differently. For example, when the upper thermostat goes bad, you will notice that cold water will run out of the heater when you turn on the hot water tap. On the other hand, with a faulty lower thermostat, the water is initially hot, but it becomes cold after some time.

How to test the thermostat with a digital multimeter

Once you suspect that a thermostat is faulty, it is best practice to test and confirm that it requires a replacement.

Before testing the thermostat, confirm that the heating element is in working condition. Otherwise, an open-circuited heating element or one with a short circuit to the ground will result in some misleading measurements.

Please check here on how to test a heating element with a multimeter.

Unless physically broken, the common problems with the thermostats are due to failure in electrical continuity, which usually gets faulty due to wear and tear, unstable or poor quality power, etc. To identify the problem, you can use an analog or digital multimeter to test for continuity. 

Tools for testing water heater thermostat

Although the tools may vary according to the model, below is the list of the items you require.

  • A flat screwdriver 
  • Philips screwdriver
  • Nut driver 
  • Digital multimeter
  • Non-contact voltage tester
  • Basic technical skills

Let us now look at the steps you need to test the thermostat with a multimeter.

Step 1: Disconnect electrical supply to the heater

For safety reasons and accurate measurements, disconnect the power from the electrical panel. You can do this by turning off the breaker. To confirm that there is no power; use a meter or non-contact voltage tester at the terminals

Step 2: Remove the water heater’s access panels

Use a flat screwdriver or nut driver to remove the lower and upper thermostat access covers. Roll the insulation that covers the thermostat back and also remove the internal plastic covers. You can tape the insulating material in a place and put it out of the way as you work on the thermostat.

Step 3: Confirm that there is no power to the water heater

To avoid short circuits or electric shocks, ensure that the electrical supply is off. You can use a digital meter to measure the voltage across the thermostat terminals, which should give zero volts if off. Alternatively, use a non-contact voltage tester to confirm. 

Step 4: Confirm Reset button has not tripped

The reset button may trip when there is a problem with eth thermostat. For example, it may trip the reset switch if the thermostat has short-circuited contacts or out of calibration. Also, the reset button may trip due to a faulty heating element. 

Step 5: Disconnect the thermostat wiring

Before removing the cables, draw the wiring diagram to avoid making mistakes when reconnecting. Alternatively, take a picture using a camera or even a mobile phone. 

To physically remove the wires, use the Phillips #2 screwdriver to loosen the screw and pull each cable out. Repeat this for each of the terminals.

Step 6: Check the thermostat continuity with a digital meter

Set the digital multimeter to the lowest resistance range. Most meters have a typical low range of 200ohms and may include a tone.

Place one of the meter probes on the screw terminal on the left side of the thermostat. Place the second probe on the other terminal, still on the left side. The digital meter should display a low resistance reading, hence confirming continuity. If the meter reading is very high or open, the thermostat is faulty and will require a replacement. 

Testing water heater thermostat

Repeat the test on the terminals on the right side and also for the other thermostat.

If the thermostats are functional and the water heater still does not function properly, test the wiring and heating elements. 

Please see our guide on how to test a heating element with a digital meter.


An electric water heater uses a thermostat to maintain the water temperature at the desired level. A failure in the thermostat makes it hard to control the heating elements and the water temperature. 

Most often, the water does not get hot as per the set temperature. Fortunately, you can test a thermostat with only a few tools and basic skills. However, you need to be careful and ensure that you have disconnected the electrical power before checking the thermostat for continuity. Once you identify a faulty device, remove and replace it with a similar model.

Bath Maintenance Tankless Water Heaters

Can I Install a Water Heater Myself?

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Today, there are many offline and online tutorials and videos that provide step-by-step guides on how to install water heaters. While the information makes it look like it is easy to do the installation, it might not be a good idea to do it yourself, especially if you have never done it before. 

Most often, the tutorials will give you step-by-step instructions based on an ideal situation. However, your environment and skills are also vital and will determine how you do the work. Moreover, it is not just the physical placement; there are various issues such as the electrical system, gas piping system, venting, access, and other factors that determine performance, reliability, and safety. 

Ideally, it is advisable to seek professional help, especially if you do not have the necessary technical skills. However, if you have these, you can do the installation as long as you ensure that you adhere to all the codes, regulations, and safety precautions. 

Generally, the installation process of a hot water system is a multi-disciplinary exercise that requires knowledge in plumbing, electrical, safety, and others. Additionally, in some countries, you need to comply with relevant codes and obtain permits to perform the work. That said, while you can install the small point-of-use tankless water heaters and especially the plug-in types, you need to consider engaging a professional installer when you have large multi-user water heaters.

Risks of installing a water heater incorrectly

While proper installation and regular maintenance ensure safe and reliable operations, the system will fail when it reaches its end of service life. However, a wrong installation is risky and more dangerous than a normal failure.

Hot water systems are dangerous

Usually, problems with the electrical or gas systems are dangerous and can lead to short circuits, explosions, fires, and other situations. If you are replacing an older system, you need to safely remove it and prepare the space for the new water heater. The heaters use an energy source. This could be gas, electricity, or both, and you must ensure the safe and reliable infrastructure to safely deliver these to the heater system. Incorrect wiring could cause electric shocks or fires. Also, if your heater is propane or natural gas-powered, you need proper piping and connections, otherwise, a minor leak from poor installation may lead to fire risks and explosions. 

Also, failure to install the water heater properly could lead to pressure build-up and tank explosion. 

Voiding warranty

Most manufacturers and even insurance policies will only honor claims for systems installed according to set requirements. In most cases, they require a professional and licensed plumber or installer. Failure to do this will void the warranty or insurance cover.

Time factor

Even when you have technical skills in other fields, installing some water heater models is quite involving and may take you longer than what you save by avoiding a professional. 

Generally, installing your water heater improperly and failing to comply with relevant plumbing, building, and electrical codes could expose yourself and your family to financial, safety, and legal risks. For the above and other reasons, you may need to think twice about installing a water heater by yourself. While you will save some money, the benefits may not warrant taking the risk.

To determine if you can install your water heater by yourself, below is a typical guide on how to perform the replacement or a new installation of an electric-powered model.

How to install a water heater 

If you decide to install the water heater, below are some of the basic steps. Please note that these may vary from one type and model of a water heater to another. Other factors that affect the installation procedure include the type of fuel, whether gas or electric, tank or tankless, capacity, outdoor or indoor, and other issues. While you can install some small models such as the point of use (POUs) and other low-demand models, the procedures may be complex for larger models.

Tools to install a water heater

Below is a list of tools to do the installation.

  • A set of screwdrivers
  • Wrench
  • Flexible hoses
  • Pipe cutter
  • Plumbers tape
  • Voltage detector
  • Soldering iron or torch
  • Solder wire
  • Solder flux
  • Sandpaper cloth, dielectric connectors, etc. (optional)

Step by step instructions on how to install an electric water heater

In our guide, we are assuming that you are replacing a defective system. You will, therefore, first remove the old one and then install the new heater.

Switch off the electrical supply to the water heater

Before working on the water heater, disconnect the power at the panel. Ideally, switch off the water heater’s circuit breaker. Use a voltage detector to ensure that the wires at the heater do not have any power. 

electric circuit breaker

Empty the tank 

If you are replacing a storage-based water heater, empty the tank by

  • Open one of the hot water outlets and letting the water run until it is cold.
  • Afterward, turn off the water heater cold water supply.
  • Use the drain valve to remove all the water from the tank. You may use a hosepipe to pour the water outside or into a sink.
  • To drain the tank faster and allow air to move in, open the hot water faucet and the T&P valve.

Physically disconnect the electrical wires

To avoid confusion, sketch the wiring diagram before removing the wires. If possible, take a photo of the wiring before disconnecting. 

Remove the electrical wires supplying the water heater. Before touching the cables, confirm again that the circuit breaker is off and that they are not carrying any current. As you remove each wire, ensure that you label or mark them appropriately.

Detach the water pipes 

Remove both the water input and output pipes. If the pipe is damaged, you may cut the pipe, but leave as much of the good part as possible. However, if the pipe is still in a good position, you can use it with the new unit, and you need to remove it carefully.

Replace the water heater

Remove the old empty water heater and move it out of the way.

Place the new heater and align it well so that electrical and plumbing connections will fit properly

Prepare the pipes

You need to prepare the old pipes by thoroughly cleaning them with sandpaper. Clean the ends that will connect to the new heater until they are shiny and free of rust and other debris.

Connect the electrical wires

Use the wiring diagram provided by the manufacturer to connect the electrical wires. Ensure that you have grounded the tank by connecting the green wire appropriately. Once done, cover the junction box securely.

install a water heater

Attach the water supply lines

  • With the unit aligned correctly, attach the cold and hot water pipes in their respective positions. 
  • If not already in place, a good practice is to use flexible hoses to attach the heater inlet and outlet and the cold and hot water copper pipes, respectively. The flexibility enhances safety and especially in case of an earthquake. When making connections use the plumber’s tape to line the threads and ensure tight bonding.
  • Open the nearest hot water faucet and turn on the cold water supply to the water heater.
  • Check for leakages, and if none, continue and fill the tank with water. 

Connect the temperature and pressure discharge pipe

  • Use the appropriate fitting to attach the discharge pipe to the T&P valve.
  • Ensure that the pipes’ ends and fittings are clean before attaching them.
  • You may use the solder to make the connections. 

Reconnect the electrical power supply 

Once you fill the tank with cold water, switch on the circuit breaker at the service. If all is well and the connections are correct, the power should reach the water heater. If there is no electrical power on the water heater, turn off the breaker before checking the wiring.

NB: Do not apply the power when the tank does not have enough water since this will cause the heating elements to dry fire and burn if not fully submerged. 

Supply all the hot water lines

Open each hot water outlet and let the water run for some time until it stops sputtering. Doing this removes the air from the tank and pipes.

Set the temperature at about 120 degrees Fahrenheit let the water heat for some time. The process may take a few hours to heat and reach the set temperature. While in the process, monitor the discharge pipe. If it starts dripping, know that the pressure could be too high and make the necessary adjustments.

While this guide assumes that you are replacing an old water heater, it is also applicable if you have a new unit. If installing the new system, skip the first five steps and start at step 6.

Common mistakes to avoid when installing a water heater

While the installation may vary depending on the type of water heater, energy source, environment, and other factors, there are some common mistakes that you should avoid. These include;

Incorrect water heater sizing

It is vital to ensure that the water heating system is the right size. Otherwise, a small unit will need to run for a much longer time, hence wear out much faster. 

install water heater

Similarly, a much larger system will cost more in terms of purchase and running costs. Additionally, it will take up more space and more costly accessories.

Placing the gas or electrical power shut-offs out of site

These controls must be in easy to access and visible locations for normal operations and handling emergencies. They allow you to cut off the electrical supply or flow of the gas into the tanks.  

In practice, you should never heat an empty tank. However, if the shut-off is inaccessible, it means that you must leave it on, even before you complete the installation and added water to the tanks. Consequently, immersion heating elements, which must work when in water, will overheat and burn out. Similarly, if you apply a flame to an empty tank, it will overheat and crack the tank.

Installing the water heater in a difficult location

A difficult-to-access location can be a challenge when installing and maintaining the water heater. Additionally, it may be risky to work in such as place and could also pose other hazards. Usually, the building codes recommend the minimum dimensions you require to access the water heater. They also specify the minimum floor space required to install the heater. Failure to adhere to the building codes results in difficulty installation and challenges in putting the units and tank in and out of the tight spaces.

Loose gas supply pipes and electrical wires

Ideally, you need to secure the electrical power and gas supply lines to the walls and floors to minimize vibrations, loose connections, movements, and associated risks. Also, ensure that they are out of the way from other objects to prevent damage. Where necessary, protect the lines, such as using the appropriate conduit or trunking for the electrical wires.

Other errors include

  • Mixing different metals: – increases the risk of galvanic corrosion. In case there is a need to use two types of metals. Separate them with a dielectric connector to avoid direct contact.
  • Ineffective venting of the exhaust gases in gas-powered based water heaters
  • Replacing a good and serviceable water heater
  • Poor soldering
  • Installing the wrongly sized water heater, etc


While, in most cases, nothing prevents you from installing your water heater, you need to understand what is involved, the risks and impact of your actions. What you need to know is that installing the water heater is not an average DIY project, and could lead to serious performance and safety issues. The installation requires a broad set of skills, including plumbing, electrical, ventilation, carpentry, and more, depending on the environment and where you are installing the system.

Maintenance Thermostat

Busted Water Heater

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A busted water heater leads to disruptions inconveniences, and sometimes, safety risks, and costly repairs. Despite the many benefits water heaters offer homeowners and businesses, a malfunction is likely to occur once in a while. And when this happens, you might not get your favorite hot temperature. In extreme cases, a faulty water heater may pose safety and financial risks to yourself, your family, and your property.

Generally, typical water heaters have a limited service life of about 8 to 10 years. Although regular maintenance enables you to get the best out of your investment, the water heater will eventually reach the end of its service life. At this time, you start experiencing regular leaks and other problems due to rust, tear and wear, corrosion, scale buildup, and other unavoidable failures that result from aging. 

Most of these issues compromise the integrity of the water heater hence increasing the risks of failure. In most cases, there are always signs of an impending water heater bust. 

Warning signs of a potential water heater bust 

Water heaters with metal storage tanks are the most vulnerable to failure. For example, there are risks of water leaking from the seams or loose fittings and even explosions due to rust, excess pressure, and temperature. 

This image has an empty alt attribute; its file name is old-water-heater.jpg
Old water heater Image The Blue Book

Some of the warning signs of an impending water tank bust include;

  • You have an aging water heater that is more than ten years old.
  • The water heater makes some unusual sounds, such as rumbling noises, popping, clanking, or banging as it heats up. Most often, this happens due to sediment build-up in the tank.
  • Heater produces brownish or yellowish-colored water with unusual odors. With time, water heaters accumulate minerals and from the water, and debris from corroding or rusting metallic parts.
  • Visible rust on the tank exterior, especially at the seams and around the pipe fittings.
  • Water does not heat to the temperature setting level
  • A leaking water heater due to a weak tank structure, broken seam, a crack, or a faulty T&P valve is another sign of an impending problem.

Most leaks are not always serious to cause the water heaters to completely malfunction, but you need to fix them. Some of the problems are easy to repair, while others require a plumber. 

What causes busted water heaters?

Although a busted water heater is probably not one of your top concerns, it is a common occurrence that you should prepare for. Generally, there is always the risk of rupturing, and this comes about due to aging, maintenance, structural, and operations issues. Among the most common causes of busting water heaters include;


With time, the metal that makes the water heater tanks will suffer from corrosion. The rusting weakens the affected parts that may give way when they are unable to withstand the pressure. Although some heaters have sacrificial anode rods to prevent or reduce corrosion on the critical parts, these deteriorate with time. A worn-out rod provides less protection hence resulting in corroded and weak tank walls.

A brown tint on your heater tank’s internal walls is a sign of rust that requires addressing. One way of addressing this is to check for and replace a worn-out anode rod. Additionally, monitor the exteriors for the water tank and address any corrosion issues. If you notice small leakages from the tanks, have a plumber check it because this could be a sign of pinholes and a weakened tank structure with the potential to leak significantly.

Excess internal pressure

An excessive pressure builds up inside the tank results in rupturing, especially at high temperatures. Although heaters have pressure and temperature relief valves, these are prone to failure wear and tear. A malfunctioning valve will start leaking or opening more frequently. The lack of proper control has the potential to cause serious pressure problems and busting. The risk increases at higher temperatures since this is when the pressure builds up faster. A much safer temperature to overcome this problem is between 120 and 125 degrees F.

Sediment or scale build-up

Hard water contains various minerals that, over time, will settle at the bottom of the heater tank. As time goes, a significant amount of sediment will settle at the bottom and around the heating element or burner, hence insulating it and prevent direct contact with water. As this happens, the elements cannot heat the water to the desired temperature using the normal settings and time, and will, therefore, work harder to achieve desired results.  

Eventually, this will mean overheating and accelerating the deterioration of the tank material. Some of the signs of sediment build-up include a knocking or popping sound from your water heater.

What to do when you have a busted water heater

A busted water heater presents several risks and, therefore, dangerous. Although you may not fix it by yourself, there are a few things you can do to reduce the risks and further damage, as you wait for professional help. 

  • Shut off the electrical power or gas line and water supply to the tank. If the leakage is extensive, consider powering off the entire electrical system to prevent the risk of shocks from water in contact with live conductors.
  • Take the photographs of the busted water tank, the damage, and the entire leak for investigation and insurance purposes.
  • Clean up the area, preferably starting with a wet vacuum cleaner to remove as much water as possible. Afterward, you may consider using a dehumidifier to dry out the areas at risk of growing molds due to dampness. 
  • Call a plumber or a professional with experience handling such failures. If you are not comfortable cleaning up, call the plumber after switching off the power and water. Additionally, you may report the bust to your insurance for compensation.

What to do when you have leakages

Because of the potential risks and damage a busted water tank presents, there are a few things you can do to prevent this from happening. In particular, the following are the steps to take when you notice leakage. In most cases, it is better to engage a plumber in some of these tasks. However, before you call the plumber, here are the things you can do to minimize the risks.

Busted water heater leaking
Busted water heater -leaking

Since the leaks are the signs of an impending failure, here is how to respond.

Shutdown the water supply

Stop the flow of water into the tank by turning the shutoff valve clockwise. If your system uses the lever control, turn it to the close position. In case you do not locate the shutoff valve or other means to stop the water, close the main supply to the house.

Turn off the electrical or gas supply to the heater 

Shut off the electrical power by switching off the circuit breaker at the service panel. For gas-powered systems, turn off the gas line the goes into the system. Failure to disconnect electrical power to the systems means that the heating elements will remain hot – increasing the risk of damage or fire.  

Locate the water leak

Check your water heater and identify where there is a leak. Potential areas include the seams, water inlet pipe or fitting at the top of the tank, a broken temperature and pressure (T&P) valve, drain valve, etc. In particular, look for areas that show signs of corrosion or rust. 

Fix the leakage

Depending on the location and type of leakage, take the necessary measures to fix the problem. The repair could be a simple task such as replacing a faulty T&P valve, tightening loose fittings using a pipe wrench, and more. However, it could also be a complex repair job that requires a plumber. If you cannot figure out where the problem is or do not have the necessary skills or tools to fix the leakage, consider engaging a professional plumber. 


Water heaters require regular cleaning and maintenance to ensure safe and reliable operations. However, even after doing this, problems may occur due to a variety of reasons. In particular, aging, corrosion, sediment build-up, and excessive pressure are major problems that lead to leaking water tanks and water heaters failures.

To reduce safety and financial risks associated with a busted water heater, ensure that you regularly check the system while addressing any issues. For problems that you cannot fix, shut off the power, gas, and water supply to the heater, and then call an experienced plumber.

Maintenance Tankless Water Heaters Thermostat

How to Test Heating Elements with a Multimeter

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Electric water heaters provide convenience and comfort around the house and other environments where they provide hot water for showering, dishwashing, and other applications. Today, more and more households are installing the systems due to the safety, low upfront, and maintenance costs. However, as it happens with many electrical systems, the heaters may fail due to various reasons. 

In most cases, a malfunctioning heating element, electrical system, or thermostat leads to the inability to heat water to the desired temperature. In particular, if one or more heating elements are faulty, you will notice that your water does not get hot as per the settings.

Electric water heating elements

The main work of the heating element is to convert electrical energy into heat. When electricity passes through, it will heat the surrounding water before it goes to the shower or another application area. 

Unfortunately, the electrical heating elements have limited lifespans. Most often, several conditions accelerate the deterioration hence reducing their service life. Some of the problems include mineral deposits in the water, air pockets, power surges, loose connections, faulty thermostats, and more. 

Common problems with the heating elements include burning up and breaking the continuity or short-circuiting and causing the heater to trip the circuit breaker or blow up the fuse. Also, the element material may deteriorate and increase the electrical resistance, resulting in the inability to heat the water to the set temperature.

Luckily, the elements are like consumables and, therefore, easily replaceable. That said, you need to test and ensure that the part is faulty before ordering a replacement. 

Rheem electric water heating element Image – Rheem

You have the option of calling a plumber or electrician when you cannot get hot water. However, before calling them or before ordering a replacement, you can do a few tests to determine if the elements are faulty. To do this, you need some basic technical skills and the following tools

  • Screwdriver
  • Non-contact voltage detector
  • Multimeter
  • Safety goggles
  • Gloves

Step by step testing of electric water heater elements

In practice, the elements are usually inside the water heater system. As such, it is not possible to inspect them visually. Moreover, the actual heating element has a metallic enclosure, so you cannot determine if it is working or faulty using your eyes unless it has severe physical damage. The best and effective way to test it is by checking the electrical continuity using a millimeter. Because of the voltages involved and the risks of fire and electric shocks, you need to follow various safety precautions. A typical step by step testing of a heating element is as below;

  1. Disconnect the power before working on the electric water heater. To do this, locate the water heater circuit breaker at the service panel and switch it off. If not sure about the specific breaker, turn off the entire electrical supply, assuming it will not affect other critical areas. Alternatively, use a multimeter or non-contact voltage tester to ensure there is no power at the supply input terminals.  
  • Drain the hot water in the heater. Open the hot water faucet while allowing the cold water to flow inside. Ideally, test the unit with lukewarm and not hot water. The process depends on the type of water heater and may not be necessary for some models. 
  • Locate and remove the access panel that covers the heating element. Note down the wiring to the element contacts and, if possible, draw the diagram. Loosen the screws and remove the wires from the element’s electrical contact terminals.  
electric water heating element connections
  • Check the wattage and voltage of the element. The information is usually on the nameplate or base of the heating element. To determine the electrical resistance value of the element, divide the square of the voltage by the power (watts) rating. 

            That is R= VxV /P or V2/P.  


R is the resistance

V the voltage rating

P the power rating in watts

Supposing the wattage is (P) is 3000W and voltage (V) is 240v, the resistance will be 240×240/3000 = 19.2 ohms. A good element should therefore have resistance around 20 ohms.

  • Set your millimeter to the resistance measurement and appropriate range, preferably the lowest where the calculated or expected value falls within. Please note that even if you cannot read the rating, the resistance is usually in tens of ohms and mostly less than 100 ohms.
  • Place one of the meter probes on the terminal where you have removed the wire. Put the other probe on the remaining terminal and read the result on the dial or display. If the element is functional, the reading will be closer to the figure you calculated in (4) above. Even when you have not calculated the resistance, most will read between 10 and 30 ohms.

A significant deviation indicates a faulty heating element, hence the need for a replacement. For example, a zero reading indicates a short circuit and will burn the fuse or trip the breaker. On the other hand, an infinite or very high reading (over 1000 ohms) indicates an open circuit, – which is the most common problem.

  • You will also need to test if the element is short-circuiting to the ground. To do this, place the probe on one of the contacts on the heating element. Take the second probe and touch its metal base, a metallic or grounded part of the heater system. Repeat this with the other contact. If you notice a low resistance, know that there could be leakage, and you need to replace the element.

When testing for current leakage, it is best practice to disconnect the two wires supplying the heating element.

Precautions when testing heating element

To prevent electric shocks, burns, or fires, switch off the power at the service panel before opening the unit. 

If you find a faulty element, ensure that the replacement part has exact physical dimensions and rating in terms of voltage and wattage as the broken one. For example, if you have a 120 volts element, never replace it with 240 volts even if they have the same wattage. The best practice is to take the faulty part with you so that the suppliers can give you a replacement that matches yours.

Before disconnecting the heating element, thermostat, or any other electrical component, note down or draw the wiring diagram to refer to when installing the new part. 


The electric water heater is an essential system in the house. It enhances the quality of life and comfort. However, the unit comprises various components that deteriorate or fail with time. One of the most common malfunctions is the inability to heat water to the right temperate, and it happens when one or more elements have failed. 

Luckily, with some basic technical skills and tools, you can test, identify and replace a faulty electric heating element. To do the test, disconnect the power and open the cover to access the element’s terminals. Remove the wires and use the multimeter to measure the resistance between the two terminals of the element. The electrical resistance is usually in tens of ohms, and if zero, very high, or infinite, the heating element is faulty and will require a replacement.