Lighting a pilot light safely and correctly

To light the pilot on your heater, you will turn the gas control knob to the "Pilot" position, hold a lit match or lighter to the pilot burner opening while pressing the ignition button, and keep the knob pressed for 30 to 60 seconds after the flame catches. The pilot should burn with a steady blue flame about half an inch tall. If it does not stay lit after you release the knob, wait five minutes and try again—do not attempt more than three times in a row, as gas can accumulate in the chamber.

Before you begin, locate your heater's control panel. Most units have a knob labeled with three positions: "Off," "Pilot," and "On." You will also see a small opening where the pilot burner sits, usually marked with an arrow or the word "Pilot." Some newer heaters have an electronic ignition button instead of a match-lit pilot; if yours has a button, you can skip the match step and rely on the button alone.

Key Takeaways

  • Turn the gas control knob to "Pilot" and hold a lit match or lighter to the pilot opening while pressing the ignition button for the flame to catch.
  • Keep the knob pressed down for 30 to 60 seconds after the pilot ignites so the thermocouple can heat up and hold the gas valve open.
  • The pilot flame should be steady and blue, about half an inch tall; a yellow or flickering flame means the burner needs cleaning.
  • If the pilot will not stay lit after three attempts, wait five minutes between tries and check for drafts, debris, or a faulty thermocouple before calling a technician.
  • Never force the knob or ignition button, and do not attempt to light the pilot more than three times in succession to avoid gas buildup.

Step-by-step lighting process

Start by turning the gas control knob all the way to "Off" and wait two minutes. This clears any gas that may have accumulated. Then turn the knob to "Pilot." You should hear a faint hissing sound—that is gas flowing to the pilot burner. If you hear nothing, the gas supply to your heater may be shut off at the main valve or the tank.

Hold a long lighter or a lit match close to the pilot opening. At the same time, press and hold the ignition button (or spark button) on the control panel. Keep both the match and the button pressed for three to five seconds. You should see a small flame ignite at the pilot opening. Once the flame appears, continue holding the knob in the "Pilot" position for another 30 to 60 seconds. This allows the thermocouple—a heat-sensing device—to warm up enough to tell the gas valve to stay open.

After 30 to 60 seconds, slowly release the knob. The pilot flame should remain lit. If it goes out as soon as you release the knob, the thermocouple may not have heated enough. Wait five minutes and repeat the process, this time holding the knob down for the full 60 seconds. If the pilot still will not stay lit after a second attempt, wait another five minutes before trying a third time.

What the pilot flame should look like

A healthy pilot flame is steady, blue, and about half an inch tall. The flame should not flicker or dance, and it should not be yellow or orange. If your pilot flame is yellow or orange, the burner opening is likely clogged with dust or debris. A yellow flame also burns cooler and may not heat the thermocouple enough to keep the gas valve open.

To clean a clogged pilot burner, turn the knob to "Off" and wait two minutes. Locate the small pilot burner tube—it is usually a thin metal rod or nozzle sticking out near the pilot opening. Use a straightened paperclip or a thin needle to gently poke through the opening at the tip of the burner. Do not force it; you are just clearing dust. Blow gently into the opening to dislodge any debris, then try lighting the pilot again. If the flame is still yellow after cleaning, the burner may need professional service.

Why the pilot light goes out

The most common reason a pilot light will not stay lit is that the thermocouple has cooled or is faulty. The thermocouple is a small metal rod that sits in the pilot flame and generates a tiny electrical signal that tells the gas valve to open. If the thermocouple is bent, dirty, or worn out, it cannot send that signal, and the gas valve closes automatically when you release the knob.

A second reason is a draft. If a window, door, or vent is open near your heater, moving air can blow the pilot flame out. Close nearby windows and doors, and check that no vents are directing air toward the heater. A third reason is a clogged pilot burner, which produces a weak or yellow flame that does not heat the thermocouple enough. Cleaning the burner opening (as described above) often solves this.

If the pilot light goes out repeatedly even after cleaning and closing drafts, the thermocouple or the gas valve itself may need replacement. This is a job for a may have access to technician, as it involves working with gas lines and electrical connections.

Safety steps before you start

Before lighting the pilot, make sure the area around your heater is clear of clutter, papers, and flammable materials. Keep a safe distance from the heater while lighting—at least one foot away. Do not lean over the heater or place your face directly above the pilot opening.

If you smell gas at any point, stop when ready. Turn the gas control knob to "Off," leave the room, and open windows and doors to ventilate. Do not use matches, lighters, or electrical switches. Go outside and call your gas company's emergency line or a licensed technician. A strong gas smell means there is a leak somewhere in the system.

If you hear a loud hissing or popping sound when you turn the knob to "Pilot," turn it back to "Off" right away. Wait five minutes and try again. A brief hiss is normal, but a loud or sustained sound suggests gas is building up in the chamber, which can be dangerous.

When to call a technician

If you have tried lighting the pilot three times (waiting five minutes between each attempt) and it still will not stay lit, do not keep trying. Call a licensed HVAC technician or your heater manufacturer's support line. Repeated failed attempts can allow gas to accumulate in the chamber, creating a safety hazard.

You should also call a technician if the pilot flame is yellow or orange and does not turn blue after you clean the burner opening, if you smell gas anywhere near the heater, if the heater makes unusual noises, or if the pilot light goes out frequently even after you have closed drafts and cleaned the burner. A technician can test the thermocouple, check the gas valve, and replace worn parts safely.

Frequently Asked Questions

How long should I hold the knob down after the pilot lights?

Hold the knob in the "Pilot" position for 30 to 60 seconds after the flame ignites. This gives the thermocouple time to heat up and signal the gas valve to stay open. If you release too early, the valve will close and the pilot will go out.

What if I do not have a match or lighter?

If your heater has an electronic ignition button, you do not need a match. straightforward turn the knob to "Pilot," press and hold the ignition button for three to five seconds, and the spark will light the pilot. If your heater requires a match and you do not have one, you can use a long lighter, a candle on a stick, or a thin piece of paper rolled tightly and lit at one end.

Is it normal for the pilot to go out sometimes?

An occasional pilot outage is usually caused by a draft or a temporary dip in gas pressure. However, if the pilot goes out more than once a month, something is wrong. Check for open windows or vents near the heater, clean the pilot burner opening, and if the problem continues, have a technician inspect the thermocouple and gas valve.

Can I light the pilot if the heater is very cold?

Yes, cold does not prevent the pilot from lighting. However, if your heater is in an unheated garage or basement, the gas may flow more slowly in very cold weather. If the pilot does not light on the first try, wait five minutes and try again. The gas line may just need time to pressurize.

What does it mean if the pilot lights but the main burner does not turn on?

Once the pilot is lit and holding steady, turn the knob from "Pilot" to "On." The main burner should ignite within a few seconds. If it does not, the thermostat may be set too low, the gas supply to the main burner may be blocked, or there may be an issue with the ignition system. Check the thermostat setting first, then call a technician if the burner still does not light.