The basic steps to relight a pilot light

To relight a pilot light on a gas heater, locate the control knob on the gas valve (usually on the front or side of the unit), turn it to the "Off" position, and wait five minutes for any gas to clear. Then turn the knob to "Pilot," hold down the ignition button while holding a lit lighter or long match to the pilot opening, and keep the button pressed for 30 to 60 seconds after the flame catches. Once the pilot stays lit, turn the knob back to "On" and listen for the main burner to ignite within a minute.

The exact location of the pilot opening and the shape of the control knob vary by heater model, so check your owner's manual or the label on the unit itself before you start. If you cannot find these details, take a photo of the gas valve and search for your heater's model number online — most manufacturers post instructions as PDFs.

Key Takeaways

  • Always turn the gas valve to "Off" and wait five minutes before attempting to relight the pilot to prevent gas buildup.
  • The ignition button must be held down continuously while you light the pilot and for 30 to 60 seconds afterward, or the pilot will go out when ready.
  • If the pilot light will not stay lit after three or four attempts, stop trying and call a technician — the thermocouple or gas valve may need replacement.
  • A pilot light that goes out repeatedly often signals a draft, a clogged pilot opening, or a failing thermocouple, none of which relighting will fix.

Finding the pilot light opening and control knob

The pilot light opening is a small hole or tube near the main burner, usually marked with a label or arrow on the gas valve itself. On most heaters, the control knob sits directly on the gas valve and has three positions: "Off," "Pilot," and "On." Some older models have a separate ignition button next to the knob instead of integrated into it.

If the heater is in a dark space, use a flashlight to locate the opening. The pilot opening is typically smaller than a pencil lead and may have a small metal tube pointing toward it. Do not confuse it with the main burner opening, which is much larger and sits below or beside the pilot.

Why the ignition button must stay pressed

The ignition button controls a thermocouple, a heat-sensing device that tells the gas valve to stay open. When you press and hold the button, you are manually overriding the thermocouple so gas flows to the pilot even though it is not yet hot enough to trigger the valve on its own. Once the pilot flame heats the thermocouple (usually 30 to 60 seconds), the thermocouple signals the valve to stay open without your help.

If you release the button too early, the gas valve closes when ready and the pilot goes out. This is a safety feature — it prevents gas from flowing if the pilot fails to light or if the thermocouple is broken. Patience at this step is the difference between success and having to start over.

What to do if the pilot will not light

If the lighter or match flame reaches the pilot opening but the gas does not ignite, the problem is usually a clogged pilot opening. Turn the knob to "Off," wait five minutes, and try again. If it still does not light after two or three attempts, the pilot opening may be blocked by dust or debris.

Some heaters have a small cleaning tool attached to the gas valve or included in the manual. If yours does, use it to gently clear the opening. If you do not have the tool or are unsure how to use it, stop and call a technician. Poking the opening with a wire or needle can damage the valve.

When to call a professional instead

Stop attempting to relight the pilot and call a technician if any of these happen: the pilot lights but goes out within seconds even though you held the button down for a full minute; the pilot lights but the main burner does not ignite within a minute; or the pilot goes out repeatedly over several days even after you successfully relight it.

These patterns usually mean the thermocouple is failing, the gas valve is stuck, or the pilot opening is clogged in a way you cannot clear yourself. A technician can test the thermocouple with a meter, clean the valve properly, or replace either part. Attempting to fix these yourself risks damaging the valve or creating a gas leak.

Preventing the pilot light from going out

A pilot light that goes out once and then stays lit is usually just a fluke — perhaps a draft from an open door or a temporary gas pressure dip. A pilot that goes out repeatedly, even after you relight it, often points to a draft in the heater closet or room. Check for open windows, doors, or vents near the heater and close them if possible.

If closing nearby openings does not help, the thermocouple may be wearing out or the pilot opening may be slowly clogging. Both are normal wear over time. A technician can replace the thermocouple (usually $100 to $300 in labor and parts, though costs vary by region and heater type) or clean the valve thoroughly. Relighting the pilot temporarily solves the problem, but the underlying cause will make it go out again.

Safety reminders before you start

Never attempt to relight a pilot light if you smell gas in the room. Turn off the heater, open windows and doors to ventilate, and call your gas company's emergency line or a technician. A strong gas smell means gas is leaking somewhere, and lighting a flame could be dangerous.

If the heater is in a confined space like a closet, make sure there is adequate ventilation before you light anything. Keep the area clear of flammable materials like paper, cloth, or cleaning supplies. If you are uncomfortable working near the heater or unsure about any step, call a technician — relighting a pilot is straightforward, but your safety comes first.

Frequently Asked Questions

How long should I hold the ignition button down?

Hold it for 30 to 60 seconds after the pilot flame appears. The exact time depends on how quickly the thermocouple heats up, which varies by model. If you are unsure, your owner's manual will specify the exact duration for your heater.

What if I do not have a lighter or long match?

A long lighter designed for candles or grills works best because it keeps your hand farther from the flame. If you do not have one, a long wooden match is the next best option. Do not use a short match or lighter — you risk burning your hand or not reaching the pilot opening.

Can I relight the pilot if the heater is still warm?

Yes, but wait a few minutes for the unit to cool slightly so you do not burn yourself. You do not need to wait for it to cool completely — just long enough that you can safely touch the metal around the pilot opening without pain.

Why does my pilot light go out every few days?

Repeated pilot outages usually mean a draft is blowing out the flame, the thermocouple is failing, or the pilot opening is slowly clogging. Relighting it temporarily fixes the problem, but the underlying cause will make it go out again. A technician can diagnose which one and repair it.

Is it safe to relight the pilot myself, or should I always call a technician?

Relighting a pilot light is safe if you follow the steps carefully and stop if anything seems wrong. However, if the pilot will not stay lit, the main burner does not ignite, or you smell gas, call a technician instead of continuing to troubleshoot.