Troubleshooting A Pilot Light That's Gone Out

If you have an older-style furnace with a standing pilot light, you may run into a situation in which the pilot light has gone out, prohibiting your furnace from kicking on. There are a number of reasons this might be happening. Sometimes a draft can blow the pilot light out and all you'll need to do is relight it. Other times, your furnace may be in need of actual repairs. Follow this guide to identify the cause of the issue and hopefully get your pilot light working again.

Step 1: Check the gas supply.

If there is no gas coming to the pilot light, of course it won't light! Make sure you've paid your gas bills; if you're delinquent, it could be that the gas company turned off your supply. Also, give the gas company a quick call to verify that there have not been any interruptions of service. If you establish that there is a gas supply to your home, but the pilot light is out, move on to step 2.

Step 2: Try relighting the pilot.

If your pilot light has just blown out, or if it went out due to an air bubble in the gas line, all you'll have to do is relight it. Start by turning off the gas valve to the furnace; this allows any gas that has accumulated to dissipate, so you don't have an explosion. Wait at least 5 minutes, and then turn the gas valve back on. Use a long-handled butane lighter to introduce a flame to the area directly above the pilot light. If it catches, your job is over. If it does not, go on to step 3.

Step 3: Clean the thermocouple.

Often, if the pilot light won't light, it is because the thermocouple -- a safety device in your furnace that stops the flow of gas when the pilot light is out -- is dirty. Removing any dirt or soot buildup should restore its function. The thermocouple looks like a 2-branched, thick wire and is generally found directly above the pilot light. With the pilot light off, it is safe for you to reach into this space and wipe off the thermocouple with a dry cloth. Once this has been done, try lighting the pilot light again. If it takes, you're all finished. Otherwise, you will want to call an heating repair technician, since there is likely a bigger issue causing your pilot light not to operate.