How to Light a Furnace Pilot Light
Safe Steps to Relight Your Furnace Pilot Light
Walking downstairs to a freezing house is a homeowner's nightmare. If you have an older gas furnace, the culprit is often a pilot light that has blown out due to a draft or a dirty component. While modern units use electronic ignition, thousands of homes still rely on a standing pilot light to kickstart the heating cycle.
Before you begin, it is important to understand your equipment. If you aren't sure whether you have a gas furnace vs electric furnace, check the manufacturer label on the side of the unit. Gas models will have a gas line and a small burner area where the pilot resides.
Preparation and Safety First
Safety is the absolute priority when dealing with natural gas or propane. If you smell a strong odor of rotten eggs, leave your house immediately and call your gas company. If there is no smell of gas, you can proceed with caution.
First, turn your thermostat to the 'Off' position or set it to a temperature lower than the current room temperature. This ensures the furnace doesn't try to draw a heavy flow of gas while you are working near the burner. You should also ensure the area around the furnace is clear of flammable materials.
Locate the Gas Valve
Open the furnace's front access panel. Look for a small valve knob that typically has three settings: ON, OFF, and PILOT. If the furnace was running recently, the knob will likely be in the ON position, but the flame itself will be extinguished.
Turn the knob to the OFF position and wait at least five minutes. This is a critical safety step that allows any residual gas in the combustion chamber to dissipate. While you wait, you can learn how to troubleshoot a furnace that won't heat to see if other issues might be affecting your system.
The Relighting Process
Once you have waited five minutes and the air is clear, follow these steps to relight the flame:
- Turn the gas valve knob to the PILOT position.
- Locate the pilot orifice—this is usually a small metal tube near the burner assembly.
- Prepare a long-reach butane lighter or a long fireplace match.
- Depress and hold down the PILOT knob (or a separate reset button nearby). This manually bypasses the safety seal to allow a small amount of gas to reach the pilot burner.
- While holding the button down, bring your flame to the end of the pilot tube.
- Once the pilot ignites, continue holding the knob or button down for at least 30 to 60 seconds.
Holding the button is necessary because it allows the thermocouple—a small copper rod—to heat up. The thermocouple is a safety device that tells the gas valve the flame is lit. If it stays cold, it will snap the gas valve shut as soon as you let go.
What to Do After It Lights
Slowly release the button. If the flame stays lit, congratulations! Turn the main gas valve knob to the ON position. You should hear the main burners ignite shortly after you turn the thermostat back up to a heating temperature.
If the flame flickers and dies the moment you let go of the button, you may have a faulty thermocouple or a dirty pilot orifice. If you find yourself frequently relighting the flame, it may be time to consult the experts at HVACDatabase.com to find a local technician who can perform a professional cleaning and inspection.
Common Troubleshooting Tips
If the pilot won't stay lit, consider these common causes:
- Drafts: A strong gust of wind through a window or vent can blow out the flame. Ensure your home is sealed by learning how to install weatherstripping.
- Dirty Thermocouple: Carbon buildup can insulate the sensor. A technician can gently clean this with fine sandpaper.
- Clogged Orifice: Dust or spiders can block the tiny hole where gas exits the pilot tube.
Improving Efficiency Beyond the Furnace
A working pilot light is just one part of home comfort. If your furnace is running but the house feels cold, you might have issues with your heat distribution system. For those with older homes, understanding the difference between steam vs hot water radiator heating can help you identify why some rooms aren't getting warm.
Similarly, remember that HVAC maintenance isn't just for winter. While you are checking your furnace, keep an eye on your cooling system components for the upcoming season. Knowing how to fix AC icing on the refrigerant line or when to install a hard start kit can save you money on emergency repairs later.
When to Call a Professional
Relighting a pilot light is a standard DIY task, but it has its limits. If you smell gas, see heavy soot around the burner, or if the flame is yellow instead of blue, shut the system down. A yellow flame indicates incomplete combustion and could be producing carbon monoxide.
For complex repairs or annual maintenance, you can find trusted, high-quality HVAC contractors in your area by using the directory at HVACDatabase.com. Professional technicians have the tools to check heat exchangers for cracks and ensure your home stays safe and warm all season long.