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Why Does My Water Heater Keep Tripping Its Reset Button?

A water heater’s reset button, also known as the high-limit switch or ECO (Emergency Cut-Off) switch, is a safety feature designed to shut off the heating element if the water temperature exceeds a preset limit, typically around 180°F (82°C). However, if you find yourself repeatedly needing to reset your water heater, it could indicate an underlying issue that requires attention. In this blog, we’ll discuss the common reasons why a water heater may keep tripping its reset button and what you can do to address them.

  1. Faulty Thermostat: One of the most common reasons for a water heater’s reset button to trip is a faulty thermostat. The thermostat(s) in your water heater continuously measure the temperature of the water in the tank, and if they start to malfunction it can allow the water to overheat and trip the reset button.

    Both gas and electric water heaters are equipped with thermostats. In electric water heaters, there are usually one or two of them, depending on the capacity (tank size) of the unit. These parts of generally relatively inexpensive to replace. Gas water heaters, on the other hand, usually have their thermostats integrated into the gas valve, so the entire valve typically needs to be replaced. This integrated design usually makes the repair a bit more expensive for gas heaters than for electric units.

  2. Malfunctioning High-Limit Switch: The reset switch itself can become faulty, causing it to trip even when the water temperature is within the safe range. If you suspect the high-limit switch is the issue, it’s best to have a professional plumber inspect and replace it if necessary.

    Once again, for an electric water heater the switch is usually a standalone part and is less expensive to replace that its gas counterpart that is typically part of the integrated gas valve.

  3. Heating Element Failure: In an electric water heater, a failing heating element can result in wide water temperature fluctuations. These elements can fail for a variety of reasons, including:

    a. Initial quality. Once again, cheap water heaters will have cheap parts, and they can fail far earlier than in higher-quality units.

    b. Electrical issues. This can be faulty wiring, as noted earlier, but it can other be due to things like power surges in your neighborhood.

    c. Mineral buildup. If you have hard water, minerals will tend to latch onto heating elements. Over time this not only reduces their effectiveness, but actually insulates the elements themselves and can force them to work harder to heat the water in the tank, eventually causing them to wear out early.

  4. Sediment Buildup: Over time, sediment can accumulate at the bottom of the tank, creating a barrier between the heating element and the water. This can cause the heating element to overheat and the reset button to trip. Flushing the tank regularly can help prevent sediment buildup and maintain the efficiency of your water heater.

  5. Undersized Water Heater: If your water heater is too small for your household’s hot water demand, it may struggle to keep up and overheat, causing the reset button to trip. It may be that the unit was undersized for the building from the outset, or it may be that new family members or new appliances have increased the capacity required and the old unit can no longer keep up. In this situation, you may need to consider adding a booster tank, upgrading to a larger water heater, or installing a tankless unit.
  6. Loose or Damaged Wiring: Loose or damaged wiring can lead to inconsistent electrical connections, causing the water heater to overheat and trip the reset button. This issue requires a professional plumber or electrician to inspect and repair the wiring.

    Normally you would expect that the wiring for you water heater to be well-protected and unlikely to be a problem during the expected lifetime of the unit, but if your reset button is constantly being triggered,  you should inspect the wiring. Problems can include:

    a. Age and wear. Over an extended period of time, wiring can degrade, especially if exposed to high heat or humidity.

    b. A low-quality unit. Makers of budget water heaters have to cut corners to make things cheap, so if your unit seemed to be a great deal, problems can arise much sooner than with higher-quality and reputable brands.

    c. Poor installation. A proven, licensed plumber will ensure that a water installation is done correctly, but cut-rate plumbers, handymen, or even industrious homeowners can make mistakes, including with the wiring.

    d. External damage. Mice and other pests can sometimes chew on and damage electrical wiring. Or wiring can be snagged and damaged when items are stored or moved around the unit.

    e. Corrosion. In environments with high moisture or other potential issues, corrosion of the wiring can occur and lead to poor connections.

Conclusion: If your water heater keeps tripping its reset button, it’s essential to identify and address the root cause to ensure the safety and efficiency of your system. Repeatedly resetting the water heater without resolving the issue can lead to more severe problems, such as damage to the tank or even an explosion. If you’re unsure of the cause or how to fix it, consult a professional plumber to diagnose and repair the problem. Regular maintenance, including flushing the tank and inspecting the thermostat and heating element, can also help prevent issues and keep your water heater functioning smoothly.

Updated June 3, 2024. Originally published March 22, 2023.