Quick answer
To reset an electric water heater, switch off its breaker, remove the upper access panel and press the red ECO button on the upper thermostat until it clicks. On a gas tank with a status light, turn the control to OFF, wait ten minutes and relight the pilot. Power-vent models reset by unplugging for one minute. A reset that trips again needs a repair, not another reset.
How you reset your water heater depends on what heats it, and the reset itself costs nothing: it is a button, a knob or a plug. What a reset does is clear a safety trip. What it cannot do is remove the reason the safety tripped, so treat one reset as a test and a second trip as a diagnosis.
Electric tanks: the red ECO button behind the upper panel
An electric tank resets at the ECO, the energy cut-off, also called the high-limit. It is a red button on the upper thermostat that opens both legs of the 240-volt supply when the water at the top of the tank gets far hotter than any thermostat setting should allow, roughly 80 °C.
- Switch off the double-pole breaker for the water heater. The terminals behind the panel carry 240 volts, so this step is not optional.
- Remove the upper access panel on the side of the tank, held by one or two screws, and fold the insulation back.
- Leave the plastic terminal shield in place. The red button is reachable through it or just above it.
- Press the button firmly. A click means it had tripped; no click means the ECO was not the problem.
- Refit the insulation and panel, then switch the breaker on. A cold tank needs one to two hours to recover.
Gas tanks with a status light: Honeywell and White-Rodgers controls
A gas tank with a blinking status light on the gas control has no reset button. The reset is turning the control off and relighting the pilot, which makes the electronics start over. Where the lighting instructions printed on your tank differ from the steps here, follow the tank.
- Turn the knob to OFF and wait ten minutes so any unburnt gas clears. If the status light stays on for a while after you turn the knob, wait until it goes dark.
- Turn the knob to PILOT, press and hold it down, and click the igniter button about once a second until the pilot lights. Watch through the sight glass at the base.
- Keep the knob held. The control is powered by the pilot flame heating a thermopile, so the status light can take up to 90 seconds to begin blinking.
- When the light blinks, release the knob and turn it to your temperature setting. One flash every three seconds is normal.
If the light comes back with a fault count, write the number down. The counts are explained in what the blinking light on a water heater means, and lighting is covered step by step in how to relight a water heater pilot. An over-temperature lockout on these controls does not clear by relighting, and it should not be forced.
Power-vent models reset by unplugging for a minute
A power-vent tank has a blower on top, a plastic vent pipe and a cord plugged into a wall outlet. Its control locks out after a set number of failed ignition attempts. Pull the plug, wait a full minute and plug it back in: the control restarts its sequence of blower, pressure check and ignition. If the blower runs and nothing lights, the causes are in why a power vent water heater runs but does not ignite.
What it means when the reset trips again
A second trip means a part has failed, and each fuel has its usual suspects.
- Electric, failed thermostat: the contacts weld shut, the element never switches off and the water overheats until the ECO opens.
- Electric, grounded element: a split element sheath leaks current to the tank water, so the element keeps heating with the thermostat open. This is the dangerous one, because the water at the tap can scald.
- Electric, loose or burnt wiring at a thermostat terminal, which heats the thermostat body and trips it.
- Gas, weak thermopile or dirty pilot: the control loses its own power supply and drops out.
- Gas, blocked air intake screen at the base or a blocked vent: the burner overheats its chamber and a thermal switch opens.
- Power-vent, blocked intake or exhaust: the pressure switch will not prove draft, so the control never tries to light.
Stop resetting after the second trip. If the water was scalding hot when an electric tank tripped, leave its breaker off until it has been tested. The electric side is covered further in why a water heater reset button keeps tripping.
What a water heater reset costs, and what a service visit covers that a reset does not
Pressing the button yourself is free. What costs money is finding out why it tripped, and a service visit covers the tests a reset skips: element resistance and ground checks with a meter, thermostat operation, thermopile output, burner and vent inspection, and the actual tank temperature against the setting.
- Diagnostic visit: $90–$150, credited to the repair when you proceed.
- Heating element replaced: $200–$400.
- Thermocouple on an older standing-pilot tank: $150–$300.
- Gas control valve: $400–$600.
- Most other water heater repairs: $150–$800.
On a tank past 10 years, weigh a larger repair against a $1,200–$2,500 replacement. ZK Mechanical gives the price in writing before work starts. See water heater service, book a visit or call (647) 801-1252.