How to Reset a Water Heater, Safely
- Licensed Texas plumbers
- Gas and electric, tank and tankless
- Same-day visits when the schedule allows
Before you touch anything
A reset clears a safety lockout. It does not repair whatever caused the lockout, so the question to ask first is why the heater shut itself down. A single trip after a power flicker or a storm is common in North Texas. A trip that returns in a day or two points to a failing thermostat, element, thermocouple or a heater running dangerously hot.
Three conditions mean you should stop and not reset: water on the floor or a wet insulation blanket, a smell of gas, or scorch marks and a burnt odor at the access panel. The sections below start with the safest resets and finish with the situations that need a plumber.
Electric water heater: ECO button and breaker
Electric tanks have a high-limit switch, often labeled ECO for energy cut-out, wired to the upper thermostat. When water gets too hot it opens the circuit and a red button pops out.
- Switch off the breaker feeding the heater at the panel, and confirm with a non-contact tester that the power is off at the heater.
- Remove the upper access panel and fold back the insulation. Do not touch terminals.
- Look for the red reset button on the upper thermostat. Press it firmly until it clicks.
- Check that the thermostat dial is set to about 120 degrees.
- Replace the insulation and the panel, then restore the breaker.
- Wait about an hour for a full tank to heat. If the button pops again, leave the breaker off and have the heater repaired.
Gas water heater: relighting the pilot
Gas models come in two designs, and the label on the tank, usually near the gas control, shows which one you have. Follow that label over any general advice, including this page.
Standing pilot models
The gas control has a knob marked off, pilot and on. The usual sequence is to turn the knob to off, wait five minutes so any gas can clear, then turn it to pilot, press and hold the knob while lighting the pilot with the built-in igniter button or a long lighter, hold for about a minute, release, and turn the knob to on. If the flame goes out when you release, the thermocouple may be worn, which is an inexpensive part for a plumber to replace.
Electronic ignition models
These have no standing pilot. After a lockout, turn the gas control to off, wait, then turn it back on or cycle the power to the unit if it has a switch. The control will try to light the burner on its own. A blinking LED code on the control, which the label decodes, tells the plumber what to check.
Tankless water heater: power cycle
Tankless units lock out for error conditions such as ignition failure, low flow, overheating or scale. The first step is a power cycle: unplug the unit or turn off its breaker, wait about two minutes, and restore power. Check that the gas valve and the water valves are fully open, and that the vent is not blocked. If a code returns, note it, because Rinnai, Navien, Noritz and others each list their own code tables in the manual. Repeated codes, especially ones for ignition or overheating, call for service. Our page on tankless repair covers the common ones.
What a reset can and cannot fix
This table matches the symptom you see to the reset that is safe to try and the point where to stop.
| Symptom | Safe reset to try | Stop and get service if |
|---|---|---|
| Electric, no hot water at all | ECO button and breaker | The button trips again |
| Electric, lukewarm water | Check both thermostats, then reset ECO | Water is lukewarm after an hour |
| Gas, no hot water, pilot out | Relight per the label | Pilot will not stay lit or you smell gas |
| Gas, electronic, error light | Power cycle and relight | The code returns after one cycle |
| Tankless, error code | Two-minute power cycle, check valves | The same code returns twice |
| Any type, water on the floor | None. Turn off the water and the power or gas | Always |
Safety rules that never change
Never bypass, cap or plug the temperature-and-pressure relief valve or its discharge pipe, and never wire around a high-limit switch. Those parts are the last defense against a tank explosion.
If you smell gas, which is a rotten-egg odor, do not operate switches, lighters or phones inside. Leave the house, then phone the gas utility's emergency line or emergency services from outside. In most of the DFW area that utility is Atmos Energy; the number is printed on your bill and on the meter. Stay out until it is cleared.
If the heater is in an attic and leaking, turn off the water supply to it first, then the power or gas. The leaking heater page explains what to do next.
Straight answers
How do you reset your hot water heater?
On an electric tank, switch off the breaker, press the red ECO button behind the upper panel and switch the power back on. A gas tank is relit by the steps printed on its own label. A tankless unit needs about two minutes without power.
Why does my water heater keep tripping the reset button?
A repeated trip usually means a failed thermostat, a shorted heating element or water that is getting too hot. The reset button is a safety device, so a tech should find the cause. Leave the breaker off until then.
Where is the reset button on a water heater?
On electric tanks it is a small red button on the upper thermostat behind the upper access panel. Gas tanks have no reset button; the gas control knob and pilot are used instead. Tankless units reset through a power cycle or a button on the control panel.
What should I do about a gas smell near the heater?
Do not light anything or flip switches. Leave the home immediately, then phone the gas utility or emergency services from outside. Do not return until the utility says it is safe. Do not try to relight the pilot.
Why am I suddenly out of hot water?
The common causes are a tripped breaker or ECO on an electric tank, a pilot that blew out on a gas tank, or a tankless lockout. Reset once using the steps here. If hot water does not return within an hour, a failed element, thermostat or gas valve is likely.
Water heater trouble in North Texas?
Tell us your ZIP and the symptom; the rest is sorted on the call.