The basic steps to relight a boiler pilot light

To relight your boiler's pilot light, you will need to locate the pilot light assembly (usually a small burner near the main burner), find the ignition button or knob on your boiler's control panel, and hold it down while using a long lighter or match to ignite the pilot flame. The pilot light should catch within a few seconds and burn steadily with a small blue flame. Once it is lit, release the button and wait a minute or two to confirm the flame stays on before closing the boiler door.

The exact process varies slightly depending on your boiler model and age. Older boilers may have a manual reset button you hold continuously, while newer models often have an automatic ignition system that lights the pilot when you press the button. Always check your boiler's instruction manual first—the label is usually on the front or side of the unit—because some models have specific safety steps you must follow.

Key Takeaways

  • Most boiler pilot lights can be relit by holding down the ignition button while using a lighter to ignite the pilot burner, then releasing once the flame catches.
  • If the pilot light will not stay lit after three or four attempts, the thermocouple (a safety sensor) may be faulty and will need professional replacement.
  • Never force the ignition button or hold it down longer than 30 seconds at a time, as this can flood the burner with gas and create a safety hazard.
  • If you smell gas while attempting to relight the pilot, stop when ready, leave the area, and call your gas company's emergency line.

Locating the pilot light assembly and controls

Open your boiler's access panel or door to see inside the combustion chamber. The pilot light burner is a small metal tube or nozzle, usually positioned near the main burner. Next to it or on the control panel you will see either a red or black button labeled "Pilot" or "Ignition," or a dial with settings like "Off," "Pilot," and "On."

If you cannot find these controls, do not guess. Boiler layouts differ significantly by manufacturer and age. Your instruction manual will show you exactly where to look. If you no longer have the manual, you can often find it online by searching your boiler's brand and model number—this information is printed on a label attached to the unit itself.

The step-by-step ignition process

First, turn the control knob or dial to the "Pilot" position if your boiler has one. This setting allows gas to flow to the pilot burner without igniting the main burner. Then locate the ignition button—it is usually a push button on the control panel itself.

Hold the ignition button down firmly with one hand. While holding it, use a long lighter or long fireplace match to reach the pilot burner opening and ignite the gas. You should see a small blue flame appear within a few seconds. Keep the button pressed for another 10 to 15 seconds after the flame appears to allow the thermocouple (the safety sensor that keeps the pilot lit) to warm up.

Release the button slowly and watch the pilot flame. If it stays lit and burns steadily with a blue color, you have succeeded. Wait a minute, then turn the control knob to "On" to resume normal boiler operation. If the flame goes out when ready after you release the button, wait five minutes and try again—sometimes the thermocouple needs a second attempt to heat properly.

When the pilot light will not stay lit

If the pilot light goes out within seconds of you releasing the ignition button, even after two or three attempts, the thermocouple is likely failing. The thermocouple is a small metal rod that sits in the pilot flame and generates an electrical signal that tells the gas valve to stay open. When it wears out, the valve closes as soon as you release the button, extinguishing the flame.

A faulty thermocouple cannot be fixed by relighting—it must be replaced by a may have access to technician. Attempting to hold the button down indefinitely to keep the pilot lit is unsafe and will not solve the problem. Call a boiler engineer or heating technician to inspect and replace the thermocouple.

Before you assume the thermocouple is bad, check that the pilot burner opening is not clogged with dust or debris. A blocked opening can prevent the flame from reaching the thermocouple properly. If you see visible dust or buildup, gently clean the area with a soft brush or compressed air, then try relighting.

Safety precautions while relighting

Never hold the ignition button down for more than 30 seconds at a time. Holding it longer floods the burner chamber with unburned gas, which is a fire and explosion hazard. If the pilot does not light within 30 seconds, release the button, wait five minutes for any gas to clear, and try again.

If you smell gas while attempting to relight the pilot, stop when ready. Do not continue trying to ignite it. Leave the boiler area, open windows to ventilate, and call your gas company's emergency line right away. A gas smell indicates a leak that a professional must investigate before the boiler is used again.

Make sure the boiler area is well-ventilated before you begin. Do not attempt to relight the pilot if you have recently smelled gas in the room or if the boiler has been leaking. These are signs of a problem that requires professional attention before the boiler can be safely operated.

When to call a heating technician instead

If you have attempted to relight the pilot light three or four times and it will not stay lit, do not keep trying. At that point, the issue is almost certainly a worn thermocouple, a faulty gas valve, or a problem with the ignition system itself—none of which you can fix by relighting.

You should also call a technician if the pilot light goes out repeatedly even though it stays lit when ready after you light it. This pattern often means the thermocouple is failing gradually and will need replacement soon. A technician can test the thermocouple and replace it before the boiler stops working entirely.

If you are uncomfortable working inside the boiler at all, or if you are unsure whether you have located the correct controls, call a technician rather than risk damaging the unit or creating a safety hazard. A boiler service call is far less expensive than repairing damage caused by incorrect ignition attempts.

Frequently Asked Questions

What color should the pilot light flame be?

The pilot light should burn with a steady blue flame, usually about half an inch to an inch tall. If the flame is yellow, orange, or flickering, the burner may be dirty or there may be a draft in the boiler area. A blue flame means the gas is burning cleanly and the pilot is working correctly.

How long should I hold the ignition button down?

Hold the button for 10 to 15 seconds after the flame appears, then release it slowly. Do not hold it for more than 30 seconds total, as this can flood the burner with gas. If the flame goes out after you release, wait five minutes and try again rather than holding the button longer.

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

Yes, you can relight the pilot while the boiler is warm. In fact, a warm boiler may be easier to ignite because the metal components are already at operating temperature. Just make sure the boiler has cooled enough that you can safely touch the access panel without burning yourself.

What does it mean if the pilot light keeps going out after I turn the boiler back on?

This usually means the thermocouple is failing or the main burner is not igniting properly, which then blows out the pilot flame. It can also indicate a draft or ventilation problem in the boiler room. A technician should inspect the boiler to identify the cause and make repairs.

Is it safe to relight the pilot light myself?

Yes, relighting a pilot light is a safe task if you follow the steps carefully and stop when ready if you smell gas. However, if the pilot will not stay lit after a few attempts, or if you are unsure about any step, contact a heating technician rather than continuing to troubleshoot.