Lighting a Boiler Pilot Light: The Basic Steps

To light a boiler pilot light, you turn the gas control knob to "Pilot," hold down the ignition button while bringing a lit match or lighter to the pilot burner opening, and keep the button pressed for 30 to 60 seconds after the flame appears. Once the pilot stays lit on its own, you turn the gas control knob to "On" and listen for the main burner to ignite within a few seconds.

The whole process takes about two minutes. If the pilot won't stay lit after you release the button, or if you smell gas at any point, stop and call a heating technician—do not keep trying.

Key Takeaways

  • The gas control knob must be set to "Pilot" before you attempt to light anything, and you must hold the ignition button down continuously while lighting.
  • You need a lit match or long lighter to reach the pilot burner opening safely; a standard lighter often does not reach far enough.
  • Keep the ignition button pressed for 30 to 60 seconds after the flame appears so the thermocouple heats up and holds the gas valve open.
  • If you smell gas, stop when ready, turn the knob to "Off," open windows, and call your heating company or gas provider.
  • If the pilot lights but goes out when you release the button, the thermocouple may be dirty or failing and needs professional inspection.

Locate the Pilot Light Assembly and Gas Control Knob

Open the boiler access panel or door. You will see a small burner opening (the pilot burner) and a control knob labeled with settings like "Off," "Pilot," and "On." The knob is usually mounted on the front of the gas valve itself, which sits near the bottom of the boiler. Some boilers have the knob on the side or back—check your boiler's manual if you cannot find it when ready.

Before you touch anything, smell the air around the boiler. If you detect a strong gas odor, do not attempt to light the pilot. Instead, turn the knob to "Off," leave the boiler area, open windows and doors, and call your gas company or heating technician. A gas smell means there may be a leak.

Set the Knob to Pilot and Prepare Your Ignition Source

Turn the gas control knob clockwise to the "Pilot" position. Do not turn it all the way to "Off"—"Pilot" is a separate setting between "Off" and "On." At this setting, a small amount of gas flows to the pilot burner, but the main burner will not ignite.

Gather your ignition source. A long-reach lighter or long fireplace match works best because the pilot burner opening is often recessed and difficult to reach with a standard lighter. If you only have a short lighter, you may need to angle it carefully or use a match instead. Have your ignition source ready before you proceed to the next step.

Press the Ignition Button and Light the Pilot

Press and hold the ignition button (usually a red or black button near the gas control knob) with one hand. While holding it down, bring your lit match or lighter to the pilot burner opening with your other hand. You should see a small blue flame appear within a few seconds. If the burner does not light after 10 seconds, release the button, wait 30 seconds, and try again—holding the button too long can flood the burner with gas.

Once the pilot flame appears, keep the ignition button pressed down. Do not release it yet. The button must stay pressed for 30 to 60 seconds so the thermocouple (a heat-sensitive device near the flame) warms up enough to hold the gas valve open on its own.

Release the Button and Check if the Pilot Stays Lit

After 30 to 60 seconds, slowly release the ignition button. Watch the pilot flame closely. If it stays lit and burns steadily, you have succeeded at this step. If the flame goes out when ready or within a few seconds, the thermocouple is not hot enough yet, or it may be faulty. Wait 30 seconds and repeat the process, this time holding the button for the full 60 seconds.

If the pilot lights and stays lit after you release the button, proceed to the next step. If it goes out repeatedly even after holding the button for a full minute, stop trying. The thermocouple may need cleaning or replacement, which requires a heating technician.

Turn the Knob to On and Listen for the Main Burner

Once the pilot is burning steadily on its own, turn the gas control knob counterclockwise from "Pilot" to "On." Within a few seconds, you should hear a click or whoosh sound as the main burner ignites. The main burner flame should be blue and steady, not yellow or orange (which can indicate incomplete combustion).

If the main burner does not ignite within 10 seconds, turn the knob back to "Off," wait a minute, and try again. If it still does not light after a second attempt, turn the knob to "Off" and call a heating technician. Do not keep trying—repeated failed ignitions can allow gas to build up in the combustion chamber.

What to Do If Something Goes Wrong

If you smell gas at any point during the process, stop when ready. Turn the gas control knob to "Off," leave the boiler area, open windows and doors to ventilate, and call your gas company's emergency line or a heating technician. Do not use electrical switches, lighters, or anything that could create a spark.

If the pilot lights but the main burner does not ignite, turn the knob to "Off" and wait a few minutes before trying again. If this happens more than once, the ignition system or burner may need professional service. If the pilot will not light at all after three attempts, or if it lights but goes out as soon as you release the button, stop and contact a heating technician. Continuing to try can waste gas and create a safety hazard.

Frequently Asked Questions

How long should I hold the ignition button down?

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 early, the pilot will go out. If you hold it longer than 60 seconds, you are not gaining anything—the thermocouple reaches full temperature well before that.

What if I cannot reach the pilot burner with my lighter?

Use a long fireplace match or a long-reach lighter instead. If neither works, you may need to remove the boiler access panel further or angle your hand differently. Check your boiler manual for the exact location and any removable components. If you still cannot reach it safely, call a technician rather than forcing it.

Is it normal for the pilot to go out on its own sometimes?

Occasional pilot outages can happen due to drafts, a dirty thermocouple, or a failing thermocouple. If it goes out once every few months, it is usually not urgent. If it goes out multiple times per week, the thermocouple likely needs cleaning or replacement—contact a heating technician to inspect it.

Can I light the pilot if I smell a faint gas odor?

No. Even a faint gas smell means there may be a leak somewhere in the system. Turn the knob to "Off," ventilate the area, and call your gas company or a heating technician before attempting to light anything. A small leak can become dangerous if you introduce a flame.

What does the main burner flame look like when it is working correctly?

The main burner flame should be blue and steady, with perhaps a small yellow tip at the very top. A flame that is mostly yellow or orange, or one that flickers wildly, means the burner is not burning fuel efficiently and needs professional cleaning or adjustment.