Home Renovation

Step by step shortcut tricks on how to repair a water heater

An electric water heater is a simple device that has a simple circuit. You’ll see that it’s easy to fix or replace the thermostat sensors. But a little harder if the repair involves replacing the heating elements. In this article, we show simple tricks on how to repair a water heater. This method can be applied for winter room heater.

How to repair a water heater

How to repair a water heater

  1. Check if the heater circuit breaker tripped or if the fuse burned. If so, reset the switch or replace the fuse. If the situation repeats, contact an electrician to fix the circuit.
  2. Open the top panel next to the heater, and move any insulation to the side to see the thermostat sensor. To avoid electric shock, be careful not to touch any exposed wire. Press the dark red reset button near the top of the sensor to reset it. Wait a few hours
  3. Check if the water heats up and if the sensor breaks down a second time. This means that the sensor or one of the thermostats has failed. See Replace sensors. If the water does not heat, go to step 4.
  4. Test the upper heating element and the voltage that reaches it. Measure the voltage. Most residential heaters use 240 V AC. Use a multimeter to carefully check the voltage at the two upper terminals that enter the overheat/thermostat sensor. A 240 V AC system usually has a black and a red cable. They are the ones that transport the energy from the circuit breaker. If you get a reading of 240 V(AC). You will know that the heater receives the correct power. Proceed to step 5. If you do not have that reading, contact an electrician to arrange your energy provider.
  5. Test the voltage on the heating element located just below the sensor. If you do not have voltage reading on the element, replace the sensor. See Replace sensors. If you get a reading on the item, replace it. See Replace heating elements.

If there is not enough hot water

there is not enough hot water

  1. Test the water temperature by pouring hot water into a glass containing an instant-read kitchen thermometer. The temperature in the tap should be 120 degrees F (88 ° C) (Temperatures above this reading have the risk of being boiling). If you get a reading below that value, open both the top and bottom panels of your water heater. One or both sensors will have a temperature setting. Some sensors show only 1 to 3 or A to C. Others show degrees. Adjust the sensors slightly upwards. Wait a few hours and try the temperature again. Repeat until the water leaving the tap reaches the temperature of 120 degrees F (88 ° C). If you still can not reach that temperature, go to step 2.
  2. Open the lower panel of the water heater and remove the insulation to expose the lower sensor. Wait a few hours after using hot water to make sure that the upper element has completely heated the water and delivered to the lower element. Test the voltage that enters the lower sensor. If you do not have a reading of 240 V(AC). Perhaps the heater has not changed to the lower element yet (wait another hour). You have a higher sensor failing. See Replace sensors. If you have the voltage reading on the sensor, but the bottom of the tank has not been heated go to step 3.
  3. Test the voltage on the lower heating element. If you do not get voltage reading, replace the sensor. See Replace sensors. If you have read, go to step 4.
  4. Test the item before replacing it. Cut off the heater power at the fuse panel or circuit breaker. Test the cables on the upper part of the upper sensor and the needles of the water element. Remove a needle from the element, and then use the multimeter to measure the resistance along the component. The resistance should be around 13 ohms. Some digital multimeters are not accurate in this range and perhaps give zero. If the multimeter shows that the resistance is high or infinite, replace the element. It also measures each terminal to the wall of the metal tank. If you get a measure of zero, replace the element. See Replace elements.

Replace sensors

Replace sensors

  1. Cut off the heater power at the fuse panel or circuit breaker. Make sure that there is no electricity access in the heater by checking the voltage at the top of the upper sensor. You should have a zero volt reading where the energy enters the sensor.
  2. Carefully make a diagram of where each cable goes and the marks on each terminal. Mark each cable with its designated terminal.
  3. Remove each sensor cable with a screwdriver. Gently pull out the hooks on each side of the sensor and remove it.
  4. Verify that the voltage range type of the replacement sensor matches the sensor you removed. Move the replacement sensor to the clamp and reconnect the cables. You may find that the plane of the current terminals differs a bit with the original. The replacement sensor comes with a wiring diagram that can help you avoid confusion.
  5. Replace the insulation and the outer panel. Restore the power to the heater in the fuse panel or circuit breaker.

Replace the heating elements

Replace the heating elements

  1. Remove all power from the heater in the fuse or circuit panel. Verify that power is not reaching the heater through a voltage check at the top of the reheat/thermostat sensor. You should have a zero volt reading where the energy enters the sensor.
  2. Drain the heater. Cut the water to your hose and add a garden hose to the drain tap at the base of the heater. Take a hot water faucet in your home to let the air out of the heater. Turn on the drain cock and let the water come out of the heater. Do it 20 to 30 minutes.
  3. Remove both electrical needles from the heating element. Use the tool for this and remove the element. This tool looks like a giant ratchet and tube wrench with holes. In the end, to insert a screwdriver to apply torque.
  4. Place the item with the voltage and watts of the item you removed. Screw the incoming element manually until the gasket makes contact with the heater, and then adjust with the heating element key.
  5. Reconnect the wires to the heating element. Close the drain cock and re-open the water supply to the hose. The tank will begin to fill, and the air will come out of the open hot water tap. Remove the aerator from the tap to prevent it from becoming clogged with sediment from the tank when the water just starts to run. Once the water passes clean, close the key and replace the aerator. Replace the access door and reconnect the power to the heater.


If a thermostat sensor needs to be replaced, you will want to replace the other at the same time. If one fails, the other may also fail.


Before touching any wire or removing any element from the heater, make sure that the power is not reaching the heater. Make sure of this with a multimeter. After replacing an element, fill the heater with water before reconnecting the power.

Leave a Reply

Your email address will not be published. Required fields are marked *