How to relight your boiler pilot light yourself
A boiler pilot light that has gone out is usually something you can relight in a few minutes without calling a technician. The process is the same on most boilers: locate the pilot light assembly (a small burner near the bottom of the unit), find the ignition button or switch, and hold it while you light the pilot with a long lighter or match. The pilot should catch and stay lit once you release the button. If it goes out again within a few seconds, or if you cannot locate the pilot assembly, that is the moment to call a professional—a pilot that will not stay lit usually means a faulty thermocouple or gas valve, not user error.
Before you start, turn off the boiler at the main switch and wait five minutes. This clears any gas that may have accumulated while the pilot was out. Never skip this step; gas buildup is a real safety hazard.
Key Takeaways
- Turn off the boiler at the main switch and wait five minutes before attempting to relight the pilot.
- Locate the pilot light assembly (usually a small metal tube with a tiny burner) near the bottom front of the boiler.
- Hold the ignition button while lighting the pilot with a long lighter or long match, then hold the button for 30 to 60 seconds after the flame appears.
- If the pilot light goes out within seconds of releasing the button, or if you cannot find the pilot assembly, call a heating technician rather than trying again.
Locate the pilot light assembly on your boiler
Open the boiler's front access panel or door. On most residential boilers, you will see a metal box or chamber inside. The pilot light assembly is a small tube, usually brass or stainless steel, with a tiny burner at the end. It sits near the main burner—the larger burner that heats water when the boiler is running. The pilot assembly is almost always at the bottom front of the boiler, and it is small enough that you might miss it if you are not looking for it.
If you cannot find it, check your boiler's manual or take a photo of the inside and show it to a heating technician. Some older or less common boiler models have the pilot in a different location, and guessing wrong wastes time.
Turn off the boiler and wait
Locate the main power switch or control knob on the boiler. It is usually on the front or side of the unit and is clearly labeled. Turn it to the OFF position. Wait a full five minutes. This allows any unburned gas inside the boiler to disperse safely.
Do not skip this step or rush it. If gas has been leaking from the pilot assembly while it was out, five minutes of ventilation prevents a dangerous buildup. After five minutes, you can proceed to light the pilot.
Light the pilot using the ignition button
Most boilers have a red or black ignition button on the control panel or near the pilot assembly itself. Press and hold this button. At the same time, use a long lighter (the kind made for fireplaces or grills) or a long match to bring a flame to the tip of the pilot burner. You should see a small blue flame appear almost when ready.
Once the flame is lit, keep holding the ignition button for 30 to 60 seconds. This allows the thermocouple—a safety sensor near the pilot flame—to heat up and signal the gas valve that the pilot is burning. If you release the button too soon, the pilot will go out.
Release the button and check if the pilot stays lit
After 30 to 60 seconds, slowly release the ignition button. The pilot flame should remain lit. If it does, you are done. The boiler is now ready to be turned back on at the main switch.
If the pilot goes out within a few seconds of releasing the button, wait five minutes and try again. Sometimes the thermocouple needs a second attempt to heat fully. If it goes out a second time, or if it will not light at all, stop trying. A pilot that will not stay lit usually means the thermocouple is faulty, the gas valve is stuck, or there is a draft blowing out the flame. These are not problems you can fix by relighting—a heating technician needs to diagnose and repair the issue.
Turn the boiler back on
Once the pilot is lit and holding steady, return to the main control switch and turn the boiler back to the ON position. The boiler should now heat water normally. You may hear the main burner ignite a few seconds later as the boiler responds to the thermostat.
If the boiler does not fire up, or if it fires and then shuts down again, the problem is not the pilot light itself. Turn the boiler off and call a technician.
When to call a heating technician instead
Do not attempt to relight the pilot more than twice. If it goes out both times, or if you cannot locate the pilot assembly, or if you smell gas at any point, turn off the boiler and call a licensed heating technician. A pilot that will not stay lit is usually a sign of a faulty thermocouple, a dirty pilot burner, or a gas valve problem—all of which require professional repair.
Also call a technician if the pilot lights but the main burner does not fire, or if the boiler cycles on and off repeatedly. These are signs of a control board or valve issue that relighting the pilot cannot fix.
Frequently Asked Questions
What if I smell gas while trying to relight the pilot?
Stop when ready and turn off the boiler at the main switch. Open windows to ventilate the room. Do not use any electrical switches or create sparks. Call your gas company's emergency line or a licensed heating technician. A gas smell usually means a leak in the gas line or valve, which is not safe to handle yourself.
How long should I hold the ignition button?
Hold it for 30 to 60 seconds after the pilot flame appears. This gives the thermocouple time to heat up and signal the gas valve to stay open. If you release it too soon, the pilot will go out. If you hold it longer, it does not hurt—just release it once the flame is clearly established.
Can a draft blow out the pilot light?
Yes. If your boiler room has a strong draft from an open window or door, or if the boiler's access panel does not close properly, wind can extinguish the pilot. Close nearby windows and doors, and make sure the boiler panel is fully seated. If the pilot keeps going out and there is no obvious draft, the boiler may need professional service.
What if the pilot lights but the main burner does not fire?
The pilot light itself is working, but the boiler's control board or gas valve is not responding. Turn off the boiler and call a heating technician. This is not a relighting problem—it is a control system issue that requires diagnosis and repair.