How to Re-Light a Gas Furnace Pilot Light

February 10, 2016

Older gas furnaces depend on a pilot light to ignite fuel and keep your home warm in the winter. Normally, it stays lit so your furnace is ready to go when you need it. If it goes out for any reason, your furnace won’t start. However, this is no reason for panic. This happens a lot to older models, and you may be able to take care of it yourself. Read on for some tips on how to relight a pilot light on a gas furnace.

What Is a Pilot Light?

The pilot light is a small flame that stays lit so it can ignite the burners in an older gas furnace. Most modern models use an electric igniter to do the same job.

Why Did My Pilot Light Go Out?

If you discover your pilot light is out, it could be because of one of several reasons, including:

Weak flame — A pilot light should burn bright blue. If yours shows any yellow or orange, it means it’s not burning the gas efficiently enough. This can cause your thermocouple to shut off the gas valve to the pilot light.
Thermocouple malfunction — If soot or dirt builds up on the intake valve, it can limit the amount of oxygen required by the pilot light, causing it to extinguish.
Drafts — A sufficiently strong draft can blow out your pilot light, just like the candles on a birthday cake.

How to Reignite a Pilot Light on a Furnace

If you’re going to try lighting the pilot light on your heater, always check the unit’s instructions before attempting anything. Following the owner’s manual is critical for preventing damage to your unit or unsafe conditions. If you can’t find your unit’s instructions, however, you may be able to follow these steps:

Step 1: Locate the assembly for the pilot light. Where is the pilot light located on a furnace? This is normally found on the bottom of the furnace and should have a valve with “on,” “off,” and “pilot” settings as well as a “reset” button.
Step 2: Turn the valve to the “off” position and wait for at least three minutes to let the gas dissipate. If you can’t turn the knob on the valve easily with your fingers, don’t attempt anything else and call for professional help. You cannot skip this step, as leaving the gas on can result in an explosion.
Step 3: Once the three minutes are up, turn the valve to the “pilot” setting. Holding a lighted match to the nozzle, push the reset button on the pilot control panel. Hold the button down until you see the pilot flame burning bright blue again. Once it does, turn the valve to the “on” position and make sure the furnace starts.
Step 4: Wait to see if the pilot light continues to burn. If it goes out again, this probably means the nozzle is clogged. Turn everything off and try cleaning it out with a piece of thin wire. If it still won’t stay lit, you may have a broken thermocouple.

If these steps don't do the trick, or if you're unsure about exactly how to re-light your furnace's pilot light, don't hesitate to call a professional. Attempting to fix your furnace yourself could void your manufacturer's warranty, or it could even be dangerous if you don't know what you're doing.

The pros at AJ Perri, on the other hand, certainly know what they're doing. Give us a call for a furnace tune-up today! We'll inspect your unit and tell you exactly what you need to keep your pilot light lit in the future.

Frequently Asked Questions

Where is the pilot light on a gas furnace?

The pilot light is usually located toward the bottom of the furnace. You should see a valve with clearly labelled "On," "Off," and "Pilot" positions, as well as usually a "Reset" option.

Does my furnace have a pilot light or an electric igniter?

Check your unit’s owner’s manual or look up the model number online to find out what type of ignition system it has. You also may be able to tell by looking for the gas valve and pilot control knob at the bottom of your unit. If you don’t see them, you probably have an electric igniter.

How often should I check and clean my pilot light?

It’s recommended that you take a look at your natural gas furnace’s pilot light at least once a year, before the cold weather sets in if possible. If you see any signs of dirt buildup, you should shut it off and clean it using a soft brush or can of compressed air to gently remove anything from the opening. A thin wire also can be used to clear out any blockages if needed. The best option is to get an annual furnace tune-up, in which a professional will inspect your furnace and ensure your pilot light stays lit.

Should I switch to an electric igniter?

Electric igniters generally are more efficient and reliable than pilot lights. They create a spark of electricity that ignites the burners, so they don’t constantly consume gas the way a pilot light does. You may be able to save some money on your gas bills if you choose to go that route. You’ll also be reducing the risk of gas leaks, explosions, or carbon monoxide poisoning that could be caused by a faulty pilot light. Electric igniters also are maintenance-free, requiring no upkeep.

Should I hire a professional to light my pilot light instead of trying to do it myself?

Relighting a pilot light can be dangerous if you’re unfamiliar with the procedure and all the necessary safety precautions. Professionals can ensure that the work is done safely and efficiently, so you won’t have to worry about a gas leak, carbon monoxide, or an explosion. They also can take a look at your furnace as a whole to make sure it’s running as it should.

Do all gas furnaces have a pilot light?

Newer models typically have electric igniters. Your furnace will only have a pilot light if it’s a much older piece of equipment. If your pilot light is struggling to stay lit, you might want to consider upgrading your unit. A professional HVAC technician can help you decide what's best for your home.