What Can Cause an Electric Water Heater to Keep Shutting Off?

Heating Elements

• One or both heating elements may be failing. If the hot water heater has been in service for several years, these elements may have reached the end of their useful life cycle. Hard water -- dissolved minerals in the water supply -- may have coated the elements with solidified materials. The heating cycle gathers these dissolved minerals into clumps, which settle to the bottom of the tank and also jacket the elements. Encased elements have to work harder to heat the tank, and may either send false high temperature signals to the thermostat or the elements may actually be overheating the water. In either case, the water heater shuts off. Have a plumber or HVAC pro inspect the elements and replace them if necessary.

Thermostats

• The thermostat reset button may not be working properly, or the thermostat may be malfunctioning. The thermostat allows power to flow to the elements when the water inside the tank cools, and it kills the flow of electricity when the system overheats. This device is attached to the tank near a heating element. The reset is a red button on the middle of the thermostat. If you must continually reset the water heater, the elements may be bad or the thermostat has failed. If you have experience working with electricity and a multimeter, you can use this tool to check whether the thermostat is working properly. Also, make sure that insulation covers the thermostat. The insulation wraps around the entire tank, just under the metal jacket. Insulation over the thermostat prevents the device from getting a false reading from the temperature in the room.

Loose Wiring

• A loose connection may be causing a short, which can trip the breakers that control the water heater. Before checking for loose wiring or bad connections, turn off the electrical supply to the water heater. Failure to do so could lead to serious injury from electric shock. In addition to tripping breakers, loose wires pose a safety issue. Electricity may arc between them, or the “hot" wire could rest against the tank’s metal jacket, grounding through the metal. Check under the metal cover on top of the water heater. The hard wire or plug from the home’s electrical supply attaches under this cover. Check the wires that lead to and away from the thermostat and the elements. Hire a professional to make any necessary repairs to the wiring.

Breakers

• Typically, the water heater requires two 30-amp breakers for full protection against problems. A smaller set up with lower amperage breakers can cause the system to shut down as the appliance calls for heat. Upgrading breakers is a job best left to electrical contractors, since the main electrical panel carries a high current and amperage.