HVAC Troubleshooting
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How to Check the Pilot Light on a Furnace
Your house is cold, your teeth are chattering, and the thermostat says the heat is on, but you can tell it’s not. If you have an older furnace (installed before 2010), it may have a standing pilot light. A standing pilot light provides a constant flame that instantly ignites the gas coming into the furnace whenever the thermostat signals the need for heat.
When it goes out, your furnace can’t supply any heat to your home. It’s time to go check it.
Where is the pilot light on a furnace?
A gas furnace pilot light is usually located near the bottom of the front of the furnace, behind a protective access panel. Some older furnaces have a viewing window where you can see if the pilot light is lit. If it is, you should see a small blue flame. If the flame is yellow, you should call for furnace repair.
How to light a furnace pilot light
If you don’t see a flame, you can try to relight the pilot light. If you have your owner’s manual, follow the directions there. If you don’t have a physical copy, you can find many owner’s manuals online by searching the make and model. If you can’t find directions for your model, follow these steps for safely lighting a furnace pilot light
- Remove the access door. It may pop off, or you may need to loosen and remove a few screws. Put them in a safe place so you can reattach the panel easily.
- Locate the gas valve control knob, marked with Pilot, On, and Off. Turn it to the Off position to stop the flow of gas.
- Wait at least 5 minutes for the gas to dissipate. This is for your safety, to avoid any flare-ups when you relight the pilot light. Watch a video on your phone or check your social media, but wait the 5 minutes.
- Turn the knob to Pilot. Light a long lighter or a long match and bring it close to the pilot light opening as you press and hold down the reset button. If there is no reset button, press and hold down the control knob.
- Once the pilot light is lit, turn the control know to the On position. This will ensure appropriate gas flow.
If this doesn’t work, you can wait a few minutes and repeat the process. If you still can’t get it lit, call an HVAC professional for help.
Does the furnace pilot light keep going out?
If the furnace won’t ignite or the pilot light ignites but won’t stay lit, make sure it’s not because of a draft. Other issues that can cause this are a dirty or clogged pilot light or a faulty part, such as a thermocouple. Call a professional to resolve the issue.
Help prevent problems with furnace maintenance
You can help your older furnace last longer with regular furnace maintenance. This includes changing the furnace filter every 1-3 months. This filter needs to be changed year-round, as the furnace also acts as the blower for your air conditioner or heat pump.
You should also schedule a yearly furnace tune-up every fall before heating season begins. At this visit, an HVAC technician will check all of the parts, clean parts as needed, lubricate moving parts, and generally make sure your furnace is operating safely and at the highest performance it is capable of.
Is it time for furnace replacement?
In general, a gas furnace will last around 15 to 20 years. With good maintenance, some can last up to 30 years. But keep in mind, it gets less efficient as the years go by. In addition, a standing pilot light wastes natural gas. If you’re tired of high heating bills as well as more costly and more frequent furnace repairs, you’ll want to watch out for the warning signs it’s time for furnace replacement.
Interested in a new furnace?
By Anne Fonda
A Content Writer with Trane Technologies, Anne Fonda researches topics and writes for Trane® and associated residential HVAC brands. She works in collaboration with Trane Technologies subject matter experts, offering easy-to-understand, informative content on complex topics. Her goal is to help consumers make informed decisions on the products and services they need.
She has written for HVAC and other service provider websites for over 16 years. Before transitioning to web content writing, Anne had a 14-year stint as an award-winning journalist. She graduated cum laude from the University of Missouri-Columbia School of Journalism. When she’s not working, Anne enjoys playing word games, reading, gardening, spending time with family, and visiting gardens and museums.
Expert review by Kimberly Sexton, Senior Systems Engineer