Electric Water Heater Troubleshooting and Repair Guide: How to Fix Common Problems

If you're experiencing problems with your hot water supply, don't panic! With the help of the electric water heater troubleshooting guide, you can quickly and easily diagnose and fix common issues.

This easy-to-use guide is designed to help homeowners repair the most common problems found on conventional and commonly used tank-type models.

From a lack of hot water to high pitch noises, broken heating elements to thermostat issues, the guide covers a wide range of issues and provides step-by-step instructions on how to fix them.

So whether you're a DIY enthusiast or just looking to save some money on professional repairs, this repair guide is an essential resource for any homeowner.

Electric water heater troubleshooting: Key considerations

1. Safety first
2. How does the electric water heater work
3. Problem #1: No hot water or not enough hot water
4. Problem #2: Water is too hot
5. Problem #3: The breaker is tripping
6. Problem #4: Heating elements are burned out
7. Problem #5: Noise

Electric hot water heater troubleshooting - Safety first

photo: pixabay

While troubleshooting an electric water heater may seem like a difficult task, it's important to prioritize safety above all else. For safe, easy, and fast troubleshooting and repair of any problems on your electric water heater, it is recommended to seek the assistance of a qualified professional.

One of the most common reasons for an electric water heater malfunction is a lack of power to the heating elements. There can be various reasons for this issue, so it is essential to turn OFF the power to the unit (circuit breaker or fuse) before any work is carried out. Additionally, use a multi-meter to check whether the elements are energized to ensure safety.

If you would like to know more about troubleshooting various issues such as water leaks or drips, noise, sediment build-up, rotten egg smells, discolored water, bulging, corrosion, high pressure, sudden temperature increases, and other problems, this guide can be a useful resource.

How does an electric water heater work

Electric water heater

Knowing how an electric water heater works is important because it helps you understand how to maintain, troubleshoot, and repair the unit. By understanding the process, you can identify the cause of a problem and determine the appropriate solution.

Here is a simple explanation:

• Cold water from the house plumbing enters the heater tank, through the dip tube and fills the tank from bottom up.
• The upper thermostat with a pre-set temperature calls for heating and turns on the upper heating element to heat the water to the desired temperature.
• As the water warms up and reaches the set temperature, the top thermostat switches power to the bottom thermostat and heating element to maintain the desired temperature.
• When the hot water at the top of the heater tank is too high, the red reset button trips and cuts power to both heating elements.
• Hot water is drawn from the top of the unit, through the plumbing, and to the open faucet when the tap is opened for a shower or dishes.
• As the set temperature is met, water heating stops.
• While the hot water exits the tank, cold water enters and mixes with hot water, lowering the tank temperature. Once the temperature drops below the set temperature on the thermostat, the thermostat energizes the heating elements again to maintain the hot water temperature.
• The TPR or temperature pressure relief valve prevents extreme pressure in the tank, allowing excessive air or water to escape.
• For draining and tank flushing, there is a drain valve at the bottom of the tank. It is made of plastic or metal.
• Inside the storage tank, there is a sacrificial anode rod that prevents deterioration of the metal tank and other elements due to corrosion.

By understanding these basics, you can perform electric water heater troubleshooting more efficiently. It is important to note that basic electrical knowledge is necessary to troubleshoot an electric water heater safely. Additionally, proper repair assumes that the unit was installed correctly and met the manufacturer's recommendations, codes, and best practices.

Electric water heater troubleshooting: Common problems and solutions

Problem #1: There is no hot water or not enough hot water

Check the power. Confirm that there is a power supply to the unit. If not, the main switch might be off, or the circuit breaker is tripped, or the fuse is blown.

Reset button. Press the red reset button on the upper thermostat. If you still don't have hot water after 10 minutes, check if electricity is being delivered to the appliance. You can do this by checking the heater's circuit breaker on the breaker panel.

Check the voltage. If the breakers are on, use a voltage tester to check if there is any voltage at the input terminals of the upper heating element.

The voltage should be either 220/240 V or 110/120 V, depending on the model. If there is no voltage, the home's electrical system should be checked, or the thermostat replaced. If there is voltage but still no hot water, the heating element might have burned out and will need to be replaced.

Recovery rate. If there is a sudden interruption in hot water delivery, it may be due to water usage exceeding the tank capacity. In this case, wait for the heater to recover. If this is an ongoing problem, the water heater might be undersized, and you should consider buying a larger one or a tankless heater.

If the heating elements are too small, replace them with the correct model recommended by the manufacturer. If there is lime formation on the elements, perform a tank flush, and if the dip tube is broken, replace it.

Continuous operation. This problem is related to an undersized tank, small heating elements, faulty thermostat or leaks in faucets, around heat traps, fittings or heating elements. Leaking can be easily fixed by using the right sealer, Teflon tape and by tightening the element.

There are several reasons for element and thermostat failure, including:

• Improper or loose wiring: This can lead to poor electrical connection and cause the element or thermostat to malfunction. To fix this issue, refer to the wiring diagram in the user manual and rewire the connections properly.
• Shorted wiring: If the wiring is shorted, it can cause the element or thermostat to fail. This requires rewiring to fix the issue.
• Circuit overload: If the circuit is overloaded, it can cause the element or thermostat to fail due to excess heat. The solution is to reduce the load on the circuit or provide an adequate circuit to handle the load.
• High or low voltage: Voltage that is too high or too low can cause the element or thermostat to malfunction. This issue requires a professional electrician to check and fix the electrical supply.
• Grounded element or thermostat: A grounded element or thermostat can cause electrical current to flow through the tank and cause it to corrode. This requires re-wiring to fix the issue.
• Heat build-up due to loose wire: When wires are loose, they can generate heat and cause the element or thermostat to fail. Tightening the wire connections is the solution.
• Defective high limit switch: A defective high limit switch can cause the element to shut off and stop heating the water. It needs to be replaced to fix the issue.
• The thermostat is set too low. If the thermostat is set too low and the incoming cold water has a lower temperature, hot water won't be hot enough. A simple solution is to increase the temperature, but not too high, as the extreme temperature can lead to scalding burns. Follow the manufacturer recommendation - safe temperature is in the range from 120 F to 125 F. Also, a lower heating element or lower thermostat might be faulty so it must be replaced. Make sure the thermostat is firmly attached to the outside tank surface.

• Limescale build-up. If the scale is formed on the heating elements because of the hard water condition, the contact surface between the immersed elements and water is decreased and needs to be cleaned.
• Loose connections. Improper, loose wiring or thermostat is not installed properly. The thermostat has to be installed flush with the tank, firmly attached, so that it can read the temperature accurately.

Problem #2: Water is too hot

Electric water heater troubleshooting also includes safe temperatures, or not too high. For example, if the temperature of hot water is 140 F, it takes less than 5 seconds for scalding burns, while for 155 F about 1 second.

Beware of the scalding water especially if kids are around. Overheating and hot water are issues that must be fixed as soon as possible.

Check the thermostat, so the right, safe temperature is set. The thermostat has to be correctly installed on the tank (flush). The element should be checked if grounded.

One of the solutions is to install a mixing valve, so the outgoing hot water has a temperature that is safe and always constant when using.

Problem #3: The breaker is tripping

Check the electric wires; they might be shorted. Check if the heating element and thermostat are grounded. Is the breaker correct size? Find out what to do if the heater keeps tripping the breaker.

Problem #4: Heating elements are burned out

Unless the water heater is equipped with the dry-fired heating elements, the standard type can easily and instantly burn out if it is not fully submerged into the water (the tank is not full of water), even if the element is partially exposed to the air.

In such case, the element shaft becomes so soft that it can be bent by hand, a hole is burned through the surface, or there are signs of melting.

Except the mentioned dry-firing, water heater elements can fail, some sooner some later, due to; limescale build-up, voltage spikes or lighting. Find out more about element failures and solution here.

Problem #5: Water heater noise

As water heater operates for months and years, water condition in your home and area plumbing (hard water) can cause the limescale and sediment buildup on the electrical heating elements. This is one of the main reasons for the high pitched whining or hissing noise.

The tank water contains minerals that form the limescale on the element. When water is heated and is trapped inside the scale, it will form steam, making the hissing sound.

Note: The recommendation is to perform the preventive maintenance and flush the heater regularly.

To fix a problem, remove and clean the heating elements from the scale buildup. If it doesn't help, replace them.

Another solution is to install low-watt density heating elements with a larger contact surface to transfer heat to water more efficiently.

Humming sound is another "issue" that is caused by the vibration of the electric current when the element's loop is installed horizontally. To eliminate the humming noise, make sure that the element loop is positioned vertically and is tightened enough.

As can be seen from the above text, electric water heater troubleshooting is not simple and requires extensive knowledge and skills, using the necessary tools. With the voltages of 240 V, it can be dangerous to work on it, if you do not have experience. This is why it is recommended to call a professional.