How to Replace an Electric Water Heater Element - Testing Tips

Learn how to replace an electric water heater element using our easy-to-use DIY instructions.

Discover how to test, replace, and troubleshoot heating elements, including how to address common problems like grounded and open elements. But first, let's become familiar with heating elements, including how they work and what types are available.

Electric water heater elements: Things to consider

What are electric heating elements?

Electric water heater elements are immersion heater elements that energize when electricity passes through them, heating water in a tank-type heater. These heating elements include a safety device known as the high limit, which regulates the electrical current flowing through the elements.

Thermostats are attached to the heating elements, and they control the temperature of hot water. The most common electric heaters such as Rheem, AO Smith, Kenmore, GE, Whirlpool, and others usually have two thermostats and two heating elements.

These thermostats are designed to be manually adjusted and surface-mounted for contact with the external portion of the electric heater.

Thanks to the electric water heater element, which uses electricity as a power source for heating, you can install a unit almost anywhere. This is not the case with gas heaters, which rely on gas lines and require proper venting.

Note: The thermostat, heating elements, and internal wiring are factory installed. For any electrical work on the heaters, you should contact a licensed electrician. Checking water heater elements is part of regular maintenance to keep the unit in good working condition.

Types of electric water heater elements

Non-simultaneous vs. simultaneous

Most residential electric heaters are non-simultaneous, operating on 240 V and with a 4500-watt power rating. "Non-simultaneous" means that only one electric water heater element out of two operates at a time.

Simultaneous configuration, on the other hand, means that more than one electric heating element is working simultaneously.

Non-simultaneous electric heaters have a slower recovery rate than simultaneous heaters, while simultaneous heaters require greater amperage protection.

Good, better, and the best heating element type

Upper and lower heating elements are identical, and the temperature is regulated by the upper and lower thermostat and high limit device.

Electric water heater elements can vary in size, but the most common size is 12" (300 mm), and the most common shape is U-shaped, screwed into a designated female threaded connection in the tank.

Some elements are shorter, while others are longer. The shorter ones have a wider tube diameter, while the longer ones have a narrower diameter. However, both have the same heating surface.

The quality of heating elements ranges from good to better and best (premium).

The best elements are usually made of nickel and stainless steel and are known as ultra-low watt-density elements. They have a lower heat per square inch of surface area than regular elements and are usually folded back. This allows for easy installation, longer life due to lime buildup resistance, and dry-firing protection.

The electrical and wattage rating is indicated at the front of the heating element. When replacing an old heating element, use the same configuration and/or model.

The high limit device is a safety feature. The high limit switch disconnects the electrical current when the temperature reaches unsafe levels.

Since the temperature can be adjusted manually, a standard screwdriver can be used. However, most safety standards do not allow setting a temperature above 120 F.

How does it work

Both the upper and lower electric heating elements are submerged in the water, while the thermostat and high-limit switch are located on the surface.

When the lower thermostat detects that the water temperature at the bottom of the tank is lower than desired, the lower heating element is energized, and the heating process begins.

The flow of electric current is stopped when the lower thermostat senses that the hot water has reached the desired temperature.

If more water is used than what the lower heating element can heat, the upper thermostat will sense that the temperature in the upper part of the tank is lower than desired. The upper heating element is then energized, and the heating cycle starts.

If you need an electric water heater that can heat water faster than your current one, you should consider heating elements with higher wattage.

Common problems and troubleshooting tips

Dry-fired elements

If a tank water heater is not completely filled with water and the heating elements are exposed to air or air pockets, dry-firing of the elements can occur within seconds. The part of the element that was exposed to air becomes extremely hot, resulting in damage to the copper sheathing beyond repair. Such an element is deformed and can be easily bent, while the plastic sleeves melt.

To avoid such problems, it is recommended to either purchase and install a dry-fired heating element or ensure that the tank is always full so that the element is fully submerged before running the heater.

Limescale build-up

Limescale build-up on heating elements is the result of hot water and mineral deposits working together, especially in regions with hard water. Once formed on the heating elements, limescale acts as an insulator and reduces the element's effectiveness.

Furthermore, less heat is transferred to the water, and the elements are exposed to higher temperatures, leading to their failure. Regular maintenance, including cleaning and draining, is key to ensuring a long life and high performance.

Voltage spikes

Heating elements can also be affected when exposed to voltage surges caused by lightning or power surges. Common symptoms of such damage include black soot on the element head, melted plastic, and swollen or split sheaths.

Wet heating element

When there is water leakage in a water heater, it can seep into the heating element sheath and cause damage to the heating element. Water inside the sheath can corrode the element, leading to a split or swollen sheath.

Open circuit

The heating element may not show any signs of deformation, but the inner filament could be broken. The only way to check for this is to test the element for continuity. If there is no continuity, the element must be replaced.

Other reasons for element failure or improper functioning can include mechanical stress due to vibrations and fluctuating voltage supply. For example, high voltage can cause an element to burn out, while low voltage can result in low heat delivery.

Testing tips

If the hot water in your water heater is not hot enough, it does not necessarily mean that you have to replace the entire unit. The good news is that you may have a defective heating element, which is easy and inexpensive to replace. Since there are usually two electric heating elements in a water heater, it is important to check both of them to determine which one is broken. Testing the elements should be the first step in troubleshooting an electric water heater that is not producing hot water.

Testing the water heating elements is a simple process. You can test their working condition by placing the multimeter clamp on one of the wires (screws) connected to the tested element and the other to any metal part of the device. Alternatively, you can use a non-contact voltage tester. The readings should be in accordance with the manufacturer's specifications.

To determine which heating element needs to be replaced, turn the temperature up on the tested heating element and down on the other one. This will activate the heating element that you are testing.

Open up a hot water tap to start the heater. At the same time, cold water enters the unit, and the thermostat senses the change in temperature and clicks on.

Using an Amp meter, you can check for current flow. If there is no flow, you likely have a defective electric water heater element that needs to be replaced. Be sure to check the other heating element as well.

Safety first

A safer way to test the heating element is to do so when the unit is turned off and no electricity is present in the heater. It is important to turn off the breaker inside the electric panel to ensure that no electricity is present.

Once you have confirmed that there is no electricity, you can loosen the screws on the element and remove the wires.

Open element

To test the heating element, set the dial on the multimeter to Ohms and touch one of the element screws with one probe and the other screw with the other probe. For a 4,500-watt heating element, there should be 12-13 ohms of resistance. If it shows no resistance, the element is broken and must be replaced. This condition is called an open-element.

Grounded heating element

If one probe is on the element screw and the other is on the metal part of the heater, and the multimeter shows any values other than the expected resistance, the element is grounded or faulty and should be replaced.

Step-by-step instructions on how to replace an electric water heater element

Replacing the lower and upper heating elements is not a difficult task and can be done without requiring advanced knowledge or professional tools. However, for some DIY enthusiasts, the process might be time-consuming.

Tools required

• Multimeter
• Non-contact voltage tester
• Ratchet wrench and sockets
• Pliers
• Screwdrivers
• Garden hose
• Rugs

Plumbers use a variety of tools to perform their job, from basic hand tools to more specialized equipment. Use this article to find some common tools used in plumbing.

Instructions

Before replacing a broken heating element in your water heater, it is essential to ensure that you use the same flange, gasket, wattage, and voltage specifications as those on the old element. This will ensure that the new element fits perfectly and works correctly.

• Turn the power OFF to the water heater at the circuit breaker.
• Shut off the cold water supply to the unit. Open the TPR valve and nearby hot water tap to release the pressure from the tank. Follow this procedure to drain the tank, so water is below the element you are planning to replace.
  
• Remove the cover panel, insulation, and plastic cover to reach the heating element and thermostat.
• Ensure that there is no electricity once again. There should be no voltage on the element screws.
• Loosen the screws and disconnect the wires.
• Remove the heating using the right tool (depending on the element type).
• Install the new gasket (or clean the old one) and place it in the heating element.
• Put the wires back, making sure it is tight.
• Open the main water valve to fill the water tank.
• Put the insulation and cover back.
• Resume the power and run the unit.

Conclusion

The electric heating element is one of the most crucial components in electric water heaters, second only to the tank, as a faulty element can result in no hot water. Therefore, it is crucial to purchase a durable and reliable heating element that is resistant to limescale and dry-firing when replacing one.

As mentioned earlier, replacing an electric water heater element does not necessarily require professional assistance. However, it is recommended to seek help if you are unfamiliar with electrical or plumbing work.

FAQ

Can I replace the heating element without draining the tank?

No, it is necessary to drain the tank before replacing the heating element to prevent water from leaking out.

Can I use a higher wattage heating element than the original one?

No, it is important to use the same wattage heating element as the original one to prevent damage to the tank and other components.

Are electric water heater elements universal?

No, electric hot water heater elements are not universal. They come in various sizes, shapes, wattages, and voltages, depending on the type and model of the unit. It is essential to replace a broken element with the same specifications as the old one to ensure it fits correctly and works properly. Using the wrong element could damage the unit and cause safety hazards.