Posted by Orin Trask
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When the hot water runs cold or the heater trips, the first instinct is to hit the water heater reset button. But is that a quick fix or a recipe for disaster? This guide walks you through exactly what the reset does, when it’s safe, and how to avoid costly mistakes.
Water Heater Reset Button is a thermal safety device (often called a high‑limit switch) that cuts power to the heating elements when the water temperature exceeds a preset threshold. It protects the tank from overheating, which could damage the unit or cause a fire.
In most electric models the switch is mounted on the side of the tank, behind a small access panel. In gas units, the reset is part of the High Limit Switch, which shuts off the gas valve if the thermostat senses unsafe heat levels.
Before you even think about pressing the button, follow these safety checks:
If any of these steps reveal damage, skip the reset and call a pro.
Electric heaters use two heating elements and a thermostat. The reset button is part of the thermostat circuit.
Note: Some newer models use a digital control board. In those cases, the reset button may be a virtual button in the menu - follow the manual.
Gas heaters have a pilot light and a Temperature Sensor that works with the high‑limit switch.
Repeated trips are a red flag. Below are conditions that warrant a call instead of a DIY reset:
These symptoms often point to a failing heating element, a broken thermostat, or sediment buildup that needs flushing.
Even well‑meaning homeowners can slip up:
If you encounter any of the following, stop and schedule service:
Professional inspection usually includes checking the High Limit Switch, testing heating elements with a multimeter, and flushing the tank to remove sediment.
| Aspect | Electric Water Heater | Gas Water Heater |
|---|---|---|
| Primary safety device | Thermostat with built‑in reset | High‑limit switch with temperature sensor |
| Power source to cut | Circuit breaker | Gas valve |
| Typical reset location | Side panel, red button | Behind burner cover, red button |
| Post‑reset steps | Restore power, wait 30 min, test temp | Relight pilot, observe flame, test temp |
| Common failure cause | Failed heating element or thermostat | Clogged burner or faulty sensor |
It resets the high‑limit safety switch that cuts power (electric) or gas (gas heater) when the water temperature gets too high.
No. The unit must cool down and the power should be off. Pressing it hot can cause a surge that damages the thermostat.
Occasionally, when a large demand (like multiple showers) pushes temperature up. If it trips more than once a month, there’s likely a deeper issue.
They serve the same safety function but are wired differently. Electric units have a simple red button on the thermostat; gas units integrate the button with a high‑limit switch and gas valve.
Turn off power or gas, let the unit cool, inspect for water leaks, burnt wires, or corroded contacts. If everything looks okay, call a licensed technician - the internal component is likely failed.
If you’re comfortable with basic electrical or gas work and follow the manual, you can. Otherwise, a professional ensures proper wiring and compliance with local codes.
Bottom line: the reset button is a safety safeguard, not a permanent fix. Use it sparingly, follow the step‑by‑step procedures, and know when to call in a specialist. Your water heater will thank you with steady, safe hot water for years to come.