Many older gas furnaces have a standing pilot light, which serves as a small ignition flame for the gas burner. Once the burner is burning, it no longer needs the pilot. However, your furnace will turn off and on — also known as cycling — in the process of heating your home. Each time the furnace starts up again, it needs the pilot to ignite the burner. Otherwise, the furnace will just release unburned gas into your home and not provide any heat. Relighting a furnace pilot is a relatively simple task, but there are some precautions that you should take in order to ensure that it’s done safely.
Gather Needed Supplies
We generally recommend having a furnace emergency kit that you keep near the furnace. This should contain everything you need to relight the pilot and keep the area safe and clean. A good starting point is safety glasses and textured rubber gloves. You will also want to wear older clothing since you may need to lay on the ground, depending on how your furnace is configured. You will also need long-reach matches or a long-reach BBQ lighter. The usual BBQ lighter is six inches. You want 12 inches to be safe. If you don’t have a lighter or matches long enough, you can tape a shorter match to a BBQ skewer or similar metal object. That should provide plenty of length to avoid the chance of being burned.
Turn Your Thermostat Off
Shift the thermostat system slider from “Heat” to “Off.” Also, ensure that the Fan slider is set to “Auto” and not “On.” We also recommend turning the HVAC system breaker off. This can be done via your electrical panel or by removing the pull-out head from your service disconnect panel, which will generally be located outside the home near where the condenser is.
Locate the Pilot Light Assembly and Reset Switch
Furnaces generally have inspection panels that are lightweight and tend to just hang, which makes them easy to remove and reinstall. You will likely need to remove one or more of these panels in order to see the thermocouple and the L-shaped deflector. The reset switch is generally a black dial with three positions: On, Pilot and Off. There should also be a red button that can be depressed.
A common misconception is that all gas furnaces have a pilot light. This is not the case. Older furnaces generally will have a standing pilot light. But newer furnaces have electronic ignition systems. These ignition systems don’t go out like a pilot does. They can fail, however, and if you have an electronic ignition system that’s not working, you will need to contact your local heating company.
If you’re unsure whether your furnace has a pilot light or you can’t locate it, check the furnace manual. The manual will indicate which ignition system is present. If applicable, it will also have a diagram showing you where and how to access the pilot light and reset switch. If you don’t have the manual, find the model number on the furnace label and look it up online.
Disable the Gas by Setting the Reset Switch
Once you know where everything is, it’s time to disable the flow of gas. To do this, turn the black knob from the “On” position to the “Off” position. This knob should be easy to move and click into each position. If it’s not easy to move, you can use WD-40 or another general-purpose lubricant. If at that point the knob is still difficult to move, we recommend calling a professional to inspect it.
Wait for Any Remaining Gas to Dissipate
Since the pilot light was not on and thus gas was not burning, gas was likely accumulating. You’ll, therefore, need to wait for any remaining gas to dissipate. A safe rule of thumb is to wait 10 minutes. If you don’t wait, the lingering gas can combust, which can be dangerous to those nearby. The gas can also potentially start a fire.
Relight the Pilot
Light your match. Hold it in one hand. Using your other hand, press the red button. This will release gas as long as you continue to press it down. Keep it depressed as you extend the match into the furnace. The burning match head should be touching the thermocouple, which is the straight piece. The L-shaped part is a deflector. In most cases, the pilot will light in just a couple of seconds. If the pilot has been out for an extended period, it can take as long as 30 seconds. Once the pilot is lit and self-sustaining, you will want to switch the knob to the “On” position and release the red button.
Observe the Pilot
At this point, you just want to take a minute or two to ensure that the standing pilot light is burning correctly. A proper pilot light will be blue or bluish-green with a yellow tip, and it should extend just about a half-inch at the end of the thermocouple. If it doesn’t look like that, the adjustment may be off. If it’s adjusted too high, the blue flame will be noisy and perhaps jump off the thermocouple. If it’s too low, the flame will be a weak yellow color and not hot enough to open the gas valve.
Turn Your Thermostat on
If you disabled the breaker, return it to the “On” position. If you removed the pull-out head from the service disconnect, replace it. Switch the system slider on the thermostat from “Off” to “Heat.”
Observe the Furnace
Once the heat kicks on, take a moment to observe the burner. If the burner looks good, replace the inspection panels. Then, move throughout the home checking each return vent as you go to ensure that heat is being released into the home everywhere that it should.
Test Carbon Monoxide Detectors
CO2 detectors are highly recommended when you have a gas furnace due to the potential for dangerous carbon monoxide levels. Go to each location where you have a detector installed, and press the test button on the device in order to ensure that it’s working properly.
Inspect the Area Around the Furnace
Perform a final inspection of the furnace area to ensure that the furnace is properly assembled and the area is clean. Put the tools you used in a safe area in the furnace room, and close the area if applicable.
Your Local Furnace Pros in Newbury Park
Southland Heating and Air Conditioning is a family-owned and -operated HVAC company that takes a great deal of pride in serving Newbury Park and the neighboring communities. We live in the area we serve, and we have more than 50 years of combined industry experience. If your pilot light continues to go out, our expert technicians can diagnose the problem and fix it. Our company also installs, services and repairs both ducted and ductless heating and cooling systems, and we offer indoor air quality services, including duct cleaning, duct repair and replacement and UV lights. Call us today or contact us online to learn more about these services or to schedule an appointment.