The basic steps to relight a pilot light

To relight a furnace pilot light, first locate the pilot light assembly at the bottom of your furnace — it is a small tube with a tiny flame that ignites the main burner. Turn the gas control knob to the "Off" position and wait five minutes to let any gas clear. Then turn the knob to "Pilot" and hold a long lighter or lit match to the pilot opening while pressing the ignition button (or holding down the knob, depending on your model). The pilot should light within a few seconds. Once it is lit, release the button, wait 30 seconds, then turn the knob to "On".

If the pilot does not light on the first try, wait another five minutes and repeat. Do not force it — if it will not light after three attempts, stop and check for the problems listed below before trying again.

Key Takeaways

  • Always turn the gas control knob to "Off" and wait five minutes before relighting to prevent gas buildup.
  • You will need a long lighter or long match to reach the pilot opening safely without burning your hand.
  • The pilot should stay lit after you release the button; if it goes out when ready, the thermocouple may be dirty or failing.
  • If the pilot will not light after three attempts, stop and check for a clogged pilot opening or a faulty igniter before trying again.

Why your pilot light went out

A pilot light can go out for several reasons. The most common is a draft or wind blowing out the flame — this happens especially in basements with open windows or doors. A second common cause is a dirty thermocouple, the metal rod that senses the pilot flame and tells the gas valve to stay open. If the thermocouple is covered in soot or corrosion, it cannot sense the flame and shuts off the gas even after the pilot lights.

Less often, the pilot opening itself becomes clogged with dust or debris, preventing gas from flowing to the flame. A faulty igniter (the part that creates the spark) can also prevent relighting. If your pilot light goes out repeatedly after you relight it, the thermocouple is the most likely culprit and may need cleaning or replacement.

Tools and materials you will need

You need very little to relight a pilot light. A long lighter (the kind used for grills or fireplaces) is the safest tool because it keeps your hand away from the flame. A long match works as well if you do not have a lighter. Some furnaces have an electronic igniter that creates a spark, so you may not need a flame source at all — check your manual or the label on the furnace to see whether your model uses a spark igniter or requires an open flame.

If the pilot opening is clogged, you may need a small, stiff brush or a straightened paperclip to gently clear it. Do not use anything sharp enough to damage the opening itself. If you need to clean the thermocouple, a soft cloth or very fine steel wool works — avoid anything abrasive that could scratch the metal.

Safety steps before you start

Turn off the furnace at the thermostat and wait at least five minutes before attempting to relight. This allows any gas that may have accumulated to disperse. Do not skip this step — relighting without waiting can cause a small explosion or flash when the gas ignites.

Make sure the area around the furnace is clear of clutter and that you have good lighting. If you smell gas anywhere in your home, do not attempt to relight the pilot. Leave the house, call your gas company's emergency line, and wait for them to inspect the furnace. A strong gas smell means there is a leak, not just a blown-out pilot.

What to do if the pilot light will not stay lit

If the pilot lights but goes out within a few seconds or minutes, the thermocouple is almost certainly the problem. You can try cleaning it first: turn off the gas, let the furnace cool for a few minutes, then locate the thermocouple (a thin metal rod near the pilot opening). Gently wipe it with a soft cloth or very fine steel wool to remove soot. Relight the pilot and see if it stays on.

If cleaning does not work, the thermocouple has likely failed and needs replacement. This is not a difficult repair — the part costs between $15 and $30 and takes about 15 minutes to swap out — but it does require turning off the gas and unscrewing the old thermocouple from the gas valve. If you are not comfortable doing this, a furnace technician can replace it for $150 to $300 in labor plus the part cost.

When to call a furnace technician

Call a technician if the pilot light will not light after three careful attempts, if it lights but will not stay on even after cleaning the thermocouple, or if you smell gas. Also call if you hear a loud boom or see a flash when the furnace ignites — this suggests a delayed ignition, which can damage the furnace and is a safety hazard.

If your furnace is more than 15 years old and the pilot light goes out frequently, it may be time to replace the furnace rather than repair it repeatedly. A technician can assess whether repair or replacement makes more sense for your situation and budget.

Frequently Asked Questions

How long does it take to relight a pilot light?

The actual relighting takes less than a minute once you have the lighter in hand. However, you should wait five minutes after turning off the gas before you start, and another 30 seconds after the pilot lights before turning the knob to "On". Total time is usually 10 to 15 minutes.

Can I relight the pilot light myself or do I need a technician?

Most homeowners can relight a pilot light safely by following the steps on your furnace label or in your manual. If the pilot will not light, or lights but will not stay on, then a technician should diagnose the problem — it is usually a thermocouple or igniter issue that requires replacement.

What does it mean if the pilot light is yellow instead of blue?

A yellow or orange pilot flame usually means the burner is not getting enough air or the gas mixture is off. This is not an emergency, but it should be checked by a technician because it can lead to incomplete combustion and carbon monoxide buildup. Do not ignore a yellow flame.

Is it dangerous to relight a pilot light?

Relighting a pilot light is safe if you follow the steps: turn off the gas, wait five minutes, and use a long lighter to keep your hand away from the flame. The main risk is relighting without waiting, which can cause a small flash. If you smell gas, do not attempt it — call your gas company instead.

How often should a pilot light need relighting?

A healthy pilot light should stay on all winter without going out. If it goes out once or twice a season due to a draft, that is normal. If it goes out weekly or monthly, the thermocouple is probably failing and should be cleaned or replaced.