How to Test Water Heater Element

How to Test Water Heater Element

If you have seen a significant temperature drop of your water heater’s supply than before, then it is worth checking out as your element must have been experiencing failures already. It can get frustrating when your water heater only produces lukewarm to tap water, instead of hot water. This matter is a big deal, especially if your home needs hot water for house chores, like sanitizing kitchen utensils.

As several factors are affecting your water heater’s function, you can start checking first the water heater element as it is the most prevalent cause.  If you are short in money for hiring home electricians, then knowing how to test the water heater element can do you a big favor.

Avoid setting back with costly electricians and start to know how to test hot water elements and replace them if necessary, with these steps, even without a professional background in electrical works.

Easy Guide in Testing Water Heater Element

How Water Heater Element Works

To be familiarized with the water heater technicalities, it is better to know and understand first how the water heater element works. Here are the few facts that you must know:

  • The upper and lower heating elements should always be submerged into the water of the tank. Meanwhile, the thermostat and high-limit switch must be on the surface.
  • The lower thermostat senses the temperature of the water at the bottom of the tank. If the temperature is lower than what you desired, the lower heating element does the job to get energy and start processing the heating.
  • On the other hand, if the lower thermostat detects that the hot water reached the set temperature, then the current stops.
  • The upper thermostat starts to work if the water reached the upper part of the tank, where the current energizes the top element to begin the heating.
  • Having a heating element with higher wattage quickens the heating. 

Tools Needed:

These are the necessary tools you should have handy before commencing to water heater element testing:

  • Gloves and Goggles
  • Safety goggles
  • Noncontact voltage detector
  • Digital Multimeter
  • Screwdriver

Steps on How to Test a Hot Water Heater Element

Before proceeding to water heater element testing, it is a must and the best precautionary measure to wear electric shock-proof gloves and check the circuit breaker box first. In most cases, the circuit box has a label, so you will not have a hard time finding it.

If you noticed that the circuit for your water heater is flipped, you must reset your water heater. However, if it repeatedly happens already, then you might need some stern water heater repair to know the causes of power overloading.

  • Disconnect the Power Source

Most people tend to forget this crucial step on how to test a water heater element, causing them to get shocked by the current remains. At the central panel that connects the water heater, you can locate the circuit breaker that is usually in a metal box attached to the wall.

Electricians often mark each breaker with the name of the gadget or appliance that it powers, so you might see the mark “water heater” or “hot water heater” on the switch. Switch the circuit breaker of your water heater off, or if you fail to recognize its breaker, then simply shut off the entire power source for better safety.

  • Open the Metal Box Cover

To open the metal box, flip the metal cover to open it, then see the panels in place with its screws and water heater’s side. You can find one or two boards for your water heater, depending on its size. Using a Philips head screwdriver, unscrew the metal plate and ensure that you would not lose the detached screws into tiny places within your home.

  • Detach the Insulation

After dealing with the metal box, you can see a layer of cellulose or fiberglass insulation under the metal cover. Detach the insulation and keep it aside. Remember to use your safety glove and goggles while removing the insulation. Using a thermostat, check to see if it has a plastic cover. If it has one, pull out the tab and remove it.

  • Confirm if the Power is Off Already

This step only takes a while, so avoid skipping the confirming and double-checking if your power source has already been removed from your water heater. To do so, place a noncontact voltage detector close to the wire connecting the element and the thermostat.

If you are still unfamiliar with how to test an electric water heater element and to use a voltage detector, a beeping sound or light flashes from the sensor signifies that there is still electricity on the water heater. Until you see otherwise, ensure that the power is completely turned off before continuing to the next step.

  • Locate the Endpoint of the Elements in the Open Panel

As you can’t see the elements placed deep inside the open panel of the water heater, what you can only see are their endpoints. Your water heater may have one or two that depends on the size of your home. In connection, one element is around one inch long, attached to a plastic plate aided with screws.

  • Note the Readings of the Water Heater Element

After locating endpoints, you need to set first the digital multimeter to the lowest (Rx1k), equivalent to resistances time 1000Ω. Then, take a close look at the base of the water heater tank where you can see the inscribed wattage and ohms.

For instance, your water heater is 3500-watt, then the multimeter would read 16Ω. Meanwhile, 4,500-watt shows between 12 – 13Ω, and for 5,500-watt element, you will get between 10-11Ω.

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  • Read the Water Heater Element Using a Multimeter Dial

First, place one of the probes on a screw attached to the face of your water heater element by unraveling the loose end. You don’t have to choose which one goes first, as it has no terminal. However, make sure that you are only testing the element, not the other electrical parts. You can now connect the multimeter prongs to the element screw’s tip.

Check the readings shown on the multimeter and see if it is relevant to the ones mentioned on the 6. If the resistance is very low, 1Ω for instance, or does not read anything at all, then it is faulty and must immediately be replaced. If your water heater has two elements, don’t forget to check the other one, as it may also need replacement.

  • Reattach the Disconnected Parts

After reading, you can either replace the element with a new one or close it for the meantime.

First, reassemble your water heater back to its original state, starting from reconnecting the wire to the surface of the water heater element. Then, cover the exposed panel and thermostat using its plastic cover. Tighten the wire and reinstall the loosened screws. Next, fix the insulation back and turn the circuit breaker on. If you have replaced the faulty element, wait for a few minutes as the water heats up.

Remember to wear safety gloves and goggles in replacing or repairing your water heater element. Remember that you only have to follow these procedures: turn off the power, open the metal box, detach the insulation, read the water heater element’s resistance using a multimeter, replace if faulty, and reassemble the parts in place. You also need to consider calling for professional help if the problem is too severe for you to fix.

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Common Water Heater Element Problems

  • Dry-fired Elements

Dry-firing of your water heater elements occurs whenever the heating elements become exposed to air or air pockets even for a few seconds. The exposed part becomes very hot, especially when it is not full of water, resulting in copper sheathing damages beyond repair. If deformed, then it can also be easily bent as the plastic sleeves melt.

To avoid such instances, you must buy and install a dry-fired heating element and ensure it is always submerged under the water before you use the heater.

  • Limescale Build-up

As a result of combined work by hot water and mineral deposits (usually in regions with hard water), the limescale build-up on the heating elements. When the limescale formed, it acts as the insulator that worsens your heater’s function, where lesser heat transfers to the water, leading to a failure. For long life and high performance, do regular maintenance, like cleaning or draining, to your water heater.

  • Voltage Spikes

During the lightning or power surge, the heating element gets prone to a voltage surge that eventually leads to failure. You can see the black soot on the head of the component, melted plastic, or split or swollen sheath if there was a voltage spike.

  • Open Circuit

Despite the heating element shows no signs of deformation, its inner filament might be broken, so you must check its continuity. Element failure may also be caused by mechanical stress, like burn out. It is due to vibration, high, and low voltage supply. High voltage results in burn out, while low ones result in slower heat delivery.


Remember that the thermostat, internal wiring, and heating elements are all factory-installed. Aside from checking the condition of your water heater as part of your maintenance, contacting a licensed electrician for your heater’s electrical work is the right choice, especially if the problem is too complicated to fix it yourself.

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