Lighting the pilot light on most boilers takes three to five minutes and requires only a long lighter or match

The pilot light is a small flame that stays lit inside your boiler and ignites the main burner when heat is needed. If it has gone out, you can relight it yourself without calling a technician. The process is nearly identical across most residential boilers, though you should check your boiler's manual for any model-specific steps before you start.

The entire procedure involves locating the pilot light assembly, finding the ignition button, and holding a flame to the pilot burner while pressing that button. Most people succeed on the first try. If the pilot light won't stay lit after you ignite it, that signals a different problem—usually a faulty thermocouple or gas valve—and you will need a technician.

Key Takeaways

  • Turn off the boiler's gas supply at the control knob, wait five minutes, then turn it to the "Pilot" position before attempting to light it.
  • Use a long lighter or long match to reach the pilot burner opening, which is usually a small brass or steel tube inside the boiler's combustion chamber.
  • While holding the flame to the pilot burner, press and hold the ignition button (often labeled "Ignite" or "Reset") for 10 to 15 seconds.
  • Once the pilot light is burning steadily, turn the control knob to the "On" position and listen for the main burner to ignite within 30 seconds.
  • If the pilot light goes out within a few minutes of lighting it, the thermocouple may be failing and will need replacement by a technician.

Locate the pilot light assembly and control knob

Open the boiler's access panel or front door. You will see the combustion chamber—the space where the flame burns. Inside or just below this chamber, you should see a small brass or steel tube with a tiny opening. This is the pilot burner. Near it, you will find a control knob on the outside of the boiler, usually labeled with three positions: "Off," "Pilot," and "On."

If you cannot find the pilot burner or control knob, consult your boiler's manual or look for a diagram printed on the inside of the access panel. Different manufacturers position these components slightly differently, but the basic layout is consistent. Take a photo of the manual page with your phone so you can refer to it while you work.

Turn off the gas and wait before relighting

Turn the control knob all the way to "Off." This stops gas flow to both the pilot and the main burner. Wait at least five minutes. This pause allows any residual gas inside the combustion chamber to clear, which prevents a small explosion when you relight the pilot.

Do not skip this step, even if you are in a hurry. A buildup of unburned gas can ignite suddenly and forcefully when you introduce a flame. Five minutes is a standard safety interval used by all boiler manufacturers.

Set the control knob to "Pilot" and prepare your lighter

After the five-minute wait, turn the control knob to the "Pilot" position. This allows gas to flow only to the pilot burner, not the main burner. Gather a long lighter or a long fireplace match. A standard cigarette lighter or short match will not reach the pilot burner safely inside the combustion chamber. A long lighter designed for candles or grills works best.

If you do not have a long lighter, you can roll a piece of paper into a tight cone, light the wide end with a regular match, and use the narrow end to direct the flame toward the pilot burner. This takes a bit more care but works reliably.

Hold the flame to the pilot burner and press the ignition button

Position your lighter or flame at the pilot burner opening. You should see a small opening where gas exits. Hold the flame directly into or just above this opening. At the same time, press and hold the ignition button (usually located near the control knob and labeled "Ignite," "Reset," or with a spark symbol). Hold both the flame and the button for 10 to 15 seconds.

You should see a small blue flame appear at the pilot burner. If nothing happens after 15 seconds, release the button, wait 10 seconds, and try again. Repeat up to three times. If the pilot light still will not ignite, the problem is likely a gas supply issue or a faulty ignition system, and you will need a technician.

Turn the control knob to "On" and verify the main burner ignites

Once the pilot light is burning steadily with a blue flame about half an inch tall, release the ignition button and turn the control knob to the "On" position. Within 30 seconds, you should hear a soft whoosh and see the main burner flame ignite inside the combustion chamber. The main flame will be larger and brighter than the pilot light.

Listen for the boiler to settle into normal operation. You may hear the fan running and feel warm air or water beginning to circulate. If the main burner does not ignite within 30 seconds, turn the knob back to "Off," wait five minutes, and repeat the process. If it fails a second time, contact a technician.

What to do if the pilot light goes out again within minutes

If the pilot light stays lit for only a few minutes before extinguishing, the problem is almost certainly the thermocouple—a safety device that senses whether the pilot flame is burning. When the thermocouple fails, it tells the gas valve to shut off, even though the pilot is lit. This is a safety feature, not a malfunction.

A faulty thermocouple cannot be repaired at home and must be replaced by a technician. Do not attempt to bypass it or hold the ignition button down indefinitely. Order a service call and describe what happened: the pilot lights but goes out after a few minutes. This description will help the technician diagnose the problem quickly.

Frequently Asked Questions

Can I light the pilot light if the boiler is still warm?

No. Wait until the boiler has cooled completely, which usually takes 30 minutes to an hour after it has shut down. A warm combustion chamber can ignite residual gas unexpectedly. If you are unsure whether it is cool, wait longer—there is no penalty for waiting.

What if I smell gas while trying to light the pilot?

Stop when ready. Turn the control knob to "Off" and leave the boiler room. Open windows and doors to ventilate. Wait 15 minutes, then try again. If you continue to smell gas after a second attempt, do not relight the pilot. Contact your gas company or a technician—a strong gas smell can indicate a leak in the gas line.

How long should the pilot flame be?

A healthy pilot flame is typically one-quarter to one-half inch tall and burns blue with a small yellow tip. If the flame is much taller or shorter, or if it is mostly yellow, the pilot burner opening may be dirty or the gas pressure may be incorrect. A technician can clean or adjust it.

Do I need to hold the ignition button the whole time the boiler runs?

No. Release the ignition button as soon as the pilot light is burning steadily. The thermocouple will hold the gas valve open as long as the pilot flame is present. You only hold the button during the initial lighting process.

Is it normal for the pilot light to go out during a power outage?

Yes. Many boilers have electronic ignition systems that require electricity. If the power goes out, the pilot light will extinguish. When power returns, you can relight it using the steps above. Some older boilers have standing pilot lights that stay lit even during outages—check your manual to see which type you have.