The basic steps to relight a pilot light
To turn on your heater's pilot light, you will need to locate the control knob on your furnace or water heater, set it to the "Pilot" position, hold down the ignition button while holding a lit match or lighter to the pilot opening, and keep the button pressed for 30 to 60 seconds after the flame catches. Once the pilot stays lit on its own, turn the knob from "Pilot" to "On" or "Heat".
The exact location of these controls varies by model. On most furnaces, the control knob is on the front of the gas valve, usually a round dial with settings labeled "Off," "Pilot," and "On." On water heaters, the knob is typically at the bottom of the tank. Check your heater's manual or the label on the unit itself to confirm the location before you start.
If you cannot find the control knob or ignition button, or if the pilot light will not stay lit after you release the button, stop and do not force it. A pilot that will not light or will not hold a flame usually signals a problem that needs professional attention — a faulty thermocouple, a blocked pilot opening, or a gas supply issue.
Key Takeaways
- Turn the control knob to "Pilot," press and hold the ignition button, and light the pilot opening with a match or lighter while holding the button down.
- Keep the ignition button pressed for 30 to 60 seconds after the flame appears so the thermocouple can heat up and hold the gas valve open.
- Once the pilot flame stays lit after you release the button, turn the knob to "On" or "Heat" to restore normal operation.
- If the pilot will not light, will not stay lit, or if you cannot locate the controls, contact a technician rather than trying repeated attempts.
Why the ignition button must stay pressed
The ignition button does two things at once: it opens the gas valve so fuel can flow to the pilot, and it triggers the spark or heating element that lights the flame. Releasing the button too soon will shut off the gas before the pilot has a chance to ignite.
Once the pilot flame is burning, you must keep the button pressed for the full 30 to 60 seconds. During this time, the flame heats up a small metal rod called a thermocouple, which sits in the pilot flame. When the thermocouple gets hot enough, it sends a signal that tells the gas valve to stay open on its own. If you release the button before the thermocouple is warm, the valve will close and the pilot will go out.
The 30 to 60 second window is a standard safety feature. It prevents gas from flowing if there is no flame to burn it. Your heater's manual will specify the exact time for your model — some require only 20 seconds, others up to 90. Check before you start so you know how long to hold the button.
What to do if the pilot light will not stay on
If the pilot lights but goes out as soon as you release the button, the thermocouple is usually the culprit. A thermocouple that is dirty, bent, or failing will not generate enough signal to keep the valve open. In this case, the pilot will light every time you press the button, but it cannot sustain itself.
Before assuming the thermocouple is broken, check whether it is straightforward dirty. Turn off the heater, let it cool, and look at the thermocouple — it is a thin rod, usually copper or steel, sitting in the pilot flame area. If it is covered in soot or debris, gently wipe it clean with a soft cloth or fine steel wool. Then try lighting the pilot again.
If cleaning does not work, or if the thermocouple is visibly bent or corroded, it will need to be replaced. This is a job for a technician. Attempting to bend it back into shape or forcing it to work can damage the gas valve or create a safety hazard.
Safety steps before you begin
Before you touch any controls, turn off the heater completely and let it cool for at least five minutes. Do not attempt to light a pilot on a heater that is still hot or actively running.
Make sure the area around the heater is clear of flammable materials — paper, cloth, cleaning supplies, or anything else that could catch fire. Keep children and pets away while you are working with the pilot light.
If you smell gas, do not light the pilot. Turn off the heater, open windows to ventilate the space, and call your gas company or a technician. A gas smell usually means there is a leak somewhere in the system, and lighting a pilot could be dangerous.
When to call a technician instead
If the pilot light will not ignite at all — no spark, no click, no flame — the ignition system may be broken. This could be a faulty igniter, a dead battery in the ignition module, or a wiring problem. These are not repairs you should attempt yourself.
If you smell gas but cannot find a leak, or if the pilot lights but the main burner will not turn on after you switch the knob to "On," stop and call a technician. These symptoms point to problems in the gas valve, the thermostat, or the burner assembly that require professional diagnosis.
If your heater is more than 15 years old and the pilot keeps going out repeatedly, it may be time to replace the unit rather than repair it. A technician can assess whether fixing the thermocouple or other parts makes sense for your specific model and age.
Frequently Asked Questions
How long should I hold the ignition button down?
Most heaters require 30 to 60 seconds. Check your manual or the label on the unit for the exact time. If you release too early, the pilot will go out. If you hold it longer than recommended, no harm is done — the thermocouple will be fully heated and the valve will stay open.
Can I use a lighter instead of a match?
Yes. A long-handled lighter or a long match works equally well. The goal is to get a flame to the pilot opening while you hold the ignition button down. A long handle keeps your hand away from the heat.
What if the pilot light goes out after I turn the knob to "On"?
This usually means the thermocouple did not get hot enough during the 30 to 60 second hold. Try again, but this time hold the button for the full recommended time. If it still goes out, the thermocouple may be failing and will need replacement by a technician.
Is it normal for the pilot flame to be blue?
Yes. A healthy pilot flame is blue with a small yellow tip at the top. If the flame is mostly yellow or orange, the pilot opening may be clogged with dust or debris. A technician can clean it, but do not attempt this yourself if you are not confident working with gas equipment.
What should I do if I smell gas while lighting the pilot?
Stop when ready. Turn off the heater, open windows, and leave the area. Call your gas company or a technician. Do not try again until a professional has checked the system. A gas smell during pilot lighting usually means there is a leak or a problem with the gas valve.