What "reset" means for a gas water heater
A reset on a gas water heater usually means one of two things: relighting a pilot light that has gone out, or pressing the red reset button on the thermostat if the heater has shut itself down for safety. Most homeowners think of reset as "get the pilot light going again," but if your heater won't stay lit or won't heat at all, the reset button might be what you need instead. Both are straightforward enough to do yourself, though the steps differ.
Before you do anything, turn off the gas supply at the control knob on the heater itself—not at the meter. Set it to the OFF position and wait five minutes. This clears any gas that may have accumulated in the chamber, which is a safety step you should not skip.
Key Takeaways
- Always turn the gas control knob to OFF and wait five minutes before attempting any reset to clear accumulated gas safely.
- Relighting a pilot light involves turning the knob to PILOT, holding the ignition button, and watching for a small blue flame near the thermocouple.
- If your heater shuts down suddenly and won't respond to pilot relighting, locate the red reset button on the thermostat and press it once, then wait for the heater to restart.
- If the pilot light goes out repeatedly within hours or days, the thermocouple or gas valve may be failing and you should call a technician.
- Never force the gas knob or ignore a strong gas smell—both are signs to stop, ventilate the room, and call your gas company or a professional.
Relighting the pilot light step by step
After you have turned the gas knob to OFF and waited five minutes, locate the control knob on the front of the heater. You will see three positions: OFF, PILOT, and ON. Turn the knob to PILOT. Below or near the knob, you will find a small button labeled IGNITION or a spark button—this is what you press to create the spark that lights the pilot.
While holding the IGNITION button down, look through the small window or opening on the front of the heater. You are looking for a small blue flame to appear near a thin metal rod called the thermocouple. Keep holding the button for 30 seconds even after the flame appears. If you do not see a flame after 30 seconds, release the button, wait 10 seconds, and try again. Most pilots light within two or three attempts.
Once the pilot flame is steady and blue, release the ignition button and turn the gas knob from PILOT to ON. The main burner should ignite with a larger flame. If it does not, turn the knob back to OFF, wait five minutes, and repeat the process. If the pilot lights but the main burner will not ignite, the issue is likely not a straightforward reset—call a technician.
Using the red reset button on the thermostat
Some gas water heaters have a red reset button on the thermostat dial itself, usually located on the side or front of the control panel. This button is a safety device that trips when the heater detects a problem—usually a loss of flame or a temperature overshoot. If your heater has shut down completely and the pilot light is still lit, the reset button may be what you need.
To use it, first turn the gas knob to OFF and wait five minutes. Then locate the red button and press it firmly once. Do not hold it down; one firm press is enough. Turn the gas knob back to ON and listen for the ignition spark. The main burner should light within a few seconds. If it does, the reset worked. If nothing happens, turn the knob back to OFF and call a technician—repeated resets that do not hold suggest a deeper problem.
When the pilot light will not stay lit
If your pilot light goes out within hours or a day of relighting it, the problem is not a one-time accident—something is causing it to fail repeatedly. The most common culprit is a thermocouple, the thin metal rod that sits in the pilot flame. When it gets too cold or accumulates dust, it stops sending the signal that tells the gas valve to stay open, and the flame dies.
You can try cleaning the thermocouple yourself. Turn the gas to OFF, wait five minutes, and locate the thermocouple—it is the thin rod that sits directly in the pilot flame. Use a fine-grit sandpaper or a soft brass brush to gently clean the tip where it sits in the flame. Wipe away any dust with a clean cloth, then relight the pilot. If it stays lit for more than a day, the cleaning worked. If it goes out again within hours, the thermocouple is likely worn out and needs replacement—this is a job for a technician.
A second cause is a faulty gas valve that is not holding pressure. If the thermocouple looks clean and the pilot still will not stay lit, do not keep relighting it. Call a professional to inspect the valve.
Safety signs that mean you should stop and call a technician
A strong smell of gas—not the faint odor you might notice near the heater, but a sharp, unmistakable smell—means stop when ready. Do not light anything, do not use electrical switches, and do not try to relight the pilot. Open windows and doors to ventilate the room, then call your gas company's emergency line or a licensed technician. A gas leak is a serious hazard.
If the gas knob is stuck or very hard to turn, do not force it. Forcing it can damage the valve and make a leak more likely. Call a technician instead. Similarly, if you smell burning plastic or see scorch marks around the pilot area, the heater may have an electrical or component failure—stop and call for help.
If the pilot light is lit but the main burner will not ignite no matter how many times you try, or if the heater cycles on and off repeatedly, these are signs of a problem beyond a straightforward reset. A technician can diagnose whether it is a bad igniter, a clogged burner, or a valve issue.
How to know if you need a professional instead
A reset is a straightforward task if the heater responds—the pilot lights and stays lit, or the reset button restores normal operation. But if you have tried relighting the pilot three times and it will not stay lit, or if you pressed the reset button and nothing changed, the heater needs professional service. Continuing to try on your own wastes time and gas and does not fix the underlying problem.
Most water heater repairs—thermocouple replacement, gas valve service, burner cleaning—require a licensed technician. The cost of a service call is usually between $150 and $300, depending on your area and what the technician finds. If your heater is more than 10 to 12 years old and fails repeatedly, replacement may be more cost-effective than repair. A technician can advise you on that choice.
Frequently Asked Questions
How long should I wait after turning off the gas before I try to relight the pilot?
Wait at least five minutes. This gives any gas that accumulated in the combustion chamber time to disperse, which prevents a small explosion when you ignite the pilot. It feels like a long time, but it is a necessary safety step.
What if I see a yellow or orange flame instead of blue when I light the pilot?
A yellow or orange flame usually means dust or debris is in the pilot burner. Turn the gas to OFF, wait five minutes, and try to gently clean the pilot opening with a thin wire or compressed air. Relight and check the flame color. If it is still not blue after cleaning, call a technician—the burner may need professional cleaning.
Can I reset the heater if the gas smell is very strong?
No. If you smell a strong, sharp gas odor, do not attempt any reset. Open windows and doors, leave the house, and call your gas company's emergency number or a technician. A strong smell suggests a leak, not just a pilot light issue.
How often is it normal for the pilot light to go out?
A healthy pilot light should stay lit indefinitely unless there is a power outage or the heater is turned off. If it goes out more than once every few months, something is wrong. Once a year or less is acceptable; once a week or more means you need a technician to inspect the thermocouple and gas valve.
Do I need to bleed air from the gas line after a reset?
No. Residential gas lines do not need bleeding after a reset. The gas will flow normally once you turn the knob to ON. If you are unsure whether air is in the line, straightforward try to light the pilot—if it lights, the line is clear.