How to Repair a Water Heater That's Getting Too Hot

If your electric water heater gets too hot suddenly, the issue may be with the control thermostat. Find out how to test and replace your thermostat with this guide. The control thermostat regulates the hot water, between a range of 90 and 150 degrees Fahrenheit. Most electric water heaters in homes will have two thermostats: an upper and lower, which should be set to the same temperature. To repair the water heater thermostat you will need to determine which one is faulty. After running a significant amount of water, let the electric water heater sit for roughly half an hour, giving it enough time to stabilize the temperature. Shut off power to the heater and remove the access covers on the side of the tank. Pull aside the insulation and check the thermostats to see if they are properly aligned so that they come in contact with the tank wall. They should be adjusted to the same settings. Use a flat blade screwdriver to turn the dial to the highest and then lowest setting. The thermostat will make a click sound, indicating that the internal thermostat contacts open and close as they should. You can also test the continuity of the thermostat using a multi-meter, while you turn the dial to get an accurate reading. If the contacts do not open when turned to the lowest setting, the thermostat will need to be replaced. To remove the thermostat, disconnect the wires and lift it out of the spring mounting bracket. When installing the new thermostat, ensure that the mounting bracket is secure and holds the thermostat flush against the tank. If you experience suddenly too hot water in your gas water heater, the issue will most likely be the valve assembly. The gas valve controls the temperature on gas models, and if your manual adjustments to the dial do not properly set the temperature, it will need to be replaced by a qualified technician.