The basic steps to light a pilot light

To light a pilot light, locate the control knob on your appliance — usually on the front or side of the unit — and turn it to the "Pilot" setting. Hold a long lighter or lit match near the pilot opening (a small hole where you see the pilot flame should appear) while pressing and holding the ignition button. The button may be labeled "Ignite," "Start," or straightforward have a spark symbol. Keep the button pressed for 30 to 60 seconds after the flame appears, then release it slowly. If the flame stays lit after you release the button, turn the knob to "On" or the heat setting you want.

If the flame goes out when you release the button, wait five minutes for the gas to clear, then repeat the process. Some pilot lights need the button held longer — up to 90 seconds — because a thermocouple (a safety device) must heat up before it will hold the flame on its own. If you have tried three times and the pilot will not stay lit, the thermocouple may be faulty or the gas supply may be blocked.

Key Takeaways

  • Turn the control knob to "Pilot," use a lighter or match to ignite the flame at the pilot opening, and hold the ignition button for 30 to 90 seconds while the thermocouple heats up.
  • The pilot flame should be blue and steady; if it is yellow or flickering, the opening may be clogged with dust or debris.
  • If the flame dies when you release the button, wait five minutes and try again — the thermocouple needs time to reach full temperature.
  • If the pilot will not light after three attempts, check that the gas supply valve is open and that you can hear gas flowing; if gas is reaching the unit but the flame will not stay lit, the thermocouple or igniter may need replacement.

What to do if you smell gas

If you smell gas while trying to light the pilot, stop when ready and do not use a lighter or match. Turn the control knob to "Off," leave the area, and open windows or doors to ventilate. Do not flip light switches or use your phone indoors. Once outside, call your gas company's emergency line — the number is usually on your bill or in the phone book — and tell them you smell gas in your home.

A strong gas smell means gas is leaking into the room, which is a safety hazard. The gas company will send someone to check the appliance and the gas line at no cost. Do not re-enter the house or try to light the pilot again until a technician has cleared it.

Checking the pilot opening for blockages

If the pilot will not light or the flame is weak and yellow instead of blue, the pilot opening may be clogged. Turn the control knob to "Off" and let the appliance cool for at least 10 minutes. Look at the pilot opening — it is usually a small hole about the size of a pin — and see if you can spot dust, lint, or debris blocking it.

If you see a blockage, use a thin, stiff wire (a straightened paper clip works) or a needle to gently clear the opening. Do not force it or enlarge the hole. Blow gently into the opening to dislodge any remaining particles, then try lighting the pilot again. If the flame is still yellow or weak after clearing, the opening may need professional cleaning.

Confirming the gas supply is on

Before you try to light the pilot, make sure gas is actually reaching the appliance. Look for a gas supply valve — a small lever or knob on the gas line leading into the unit. The lever should be parallel to the pipe (pointing in the same direction as the gas flow). If it is perpendicular to the pipe, the gas is shut off.

Turn the lever so it is parallel to the pipe, then wait a minute for gas to reach the pilot. You may hear a faint hissing sound as gas flows. If you do not hear or smell gas after waiting, the main gas valve for your home may be off, or there may be a problem with the gas line. Check the main valve (usually near your water heater or furnace) and make sure it is open. If the main valve is on but no gas is reaching the appliance, contact your gas company.

When the thermocouple is the problem

The thermocouple is a small metal rod that sits in the pilot flame and tells the gas valve to stay open. When you hold the ignition button, you are giving the thermocouple time to heat up. Once it is hot enough, it generates a tiny electrical signal that holds the valve open on its own. If the thermocouple is dirty, bent, or worn out, it cannot generate that signal, and the flame will die when you release the button.

If you have held the button for a full 90 seconds and the flame still goes out, the thermocouple is likely faulty. You can try cleaning it: turn off the gas, let the appliance cool, and gently wipe the thermocouple rod with a soft, dry cloth or fine steel wool. Do not bend it or scrape it hard. If cleaning does not work, the thermocouple will need to be replaced by a technician — this is not a repair most people do themselves because it requires disconnecting the gas line.

Relighting after the pilot has been out for a while

If the pilot light has been off for more than a few hours, gas may have accumulated in the line. Before you try to light it, turn the control knob to "Off" and wait five minutes to let any stray gas escape. Then follow the normal lighting steps. This waiting period prevents a small explosion or a large flame when the gas ignites.

If you are relighting a pilot on a furnace or water heater that has been off all season, the same rule applies: wait five minutes after turning the knob to "Pilot" before you light it. Once the pilot is lit and holding steady, you can turn the knob to "On" or your desired heat setting.

Frequently Asked Questions

How long should I hold the ignition button?

Hold it for at least 30 seconds after the flame appears, and up to 90 seconds if the flame keeps going out. The longer you hold it, the more time the thermocouple has to heat up and signal the gas valve to stay open. If the flame is still dying after 90 seconds, the thermocouple is probably faulty.

Why is my pilot flame yellow instead of blue?

A yellow flame usually means the pilot opening is clogged with dust or the air-to-gas ratio is off. Try clearing the opening with a thin wire. If the flame is still yellow after cleaning, the appliance may need professional servicing to adjust the air shutter or replace the pilot assembly.

Can I light the pilot with a match instead of a lighter?

Yes, a lit match works just as well as a lighter. Hold the match near the pilot opening while pressing the ignition button. A long lighter or long-handled match is safer because it keeps your hand farther from the flame and the hot appliance.

What should I do if I cannot reach the pilot opening?

Some appliances have a removable access panel or cover over the pilot. Check your owner's manual or look for screws or clips holding a panel in place. If you cannot safely access the pilot after removing any covers, or if you are uncomfortable working near the gas line, contact a technician.

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

A pilot that goes out regularly usually has a faulty thermocouple, a clogged opening, or a draft blowing out the flame. A single gust from an open window or door can extinguish a pilot temporarily, but if it goes out multiple times a week without an obvious cause, the thermocouple or gas valve likely needs replacement.