Drafts are notorious for killing pilot lights. One cold breeze hits the wrong way, and suddenly your furnace decides it’s not working. It’s annoying. It’s also usually fixable without calling in a pro immediately.
But you have to be careful. Gas appliances aren’t toys. If your unit comes with specific relighting instructions, stick to them. They’re usually taped to the side of the furnace or inside the access panel. General rules can vary by model. Deviating from the manufacturer’s manual is a bad idea.
If you don’t have instructions, here is the standard procedure for relighting a standing pilot light.
Find the Control Valve
Locate the pilot light assembly. It’s usually near the bottom of the furnace. You’ll see a gas control valve with a dial. Look for three settings: ON, OFF, and PILOT.
Shut Off the Gas
Turn the dial to OFF. This stops the gas flow. You need to wait. Do not skip this step. Wait at least three minutes. This allows any accumulated gas to dissipate. If you try to light it immediately, you risk a flare-up. Breathe the air. Make sure you don’t smell gas. If you do, get out and call the gas company.
Relight the Pilot
Set the valve to PILOT. Find the reset button or igniter knob on the control panel. Press and hold it down. This opens the gas valve specifically for the pilot line.
Hold a long-reach lighter or a match to the pilot opening. Keep the button depressed. Watch for the flame. Once it catches and burns steadily, keep holding the button for another minute or so. This heats the thermocouple. The thermocouple is a safety device that proves the pilot is lit. If you let go too soon, the gas valve will shut off again.
Once the flame is strong and steady, release the button. Turn the valve dial to ON. Your furnace should now be ready to call for heat.
Why Won’t It Stay Lit?
Sometimes the pilot lights but dies almost immediately. This is frustrating.
The pilot opening might be clogged with dirt or debris. If that’s the case, turn the gas valve to OFF again. Wait three minutes. Then, use a piece of fine wire or a compressed air canister to clear the opening. Be gentle. You don’t want to damage the delicate pilot assembly.
Try relighting it again. If it still won’t stay lit, the problem is likely the thermocouple. This copper rod sits next to the pilot flame. It generates a small electrical current when heated. That current keeps the gas valve open. If the thermocouple is faulty or misaligned, the valve shuts off to prevent gas leaks.
You can often replace a thermocouple yourself. They are relatively cheap and straightforward to swap. But if you’re not comfortable working with gas lines, don’t force it. Call a professional service person.
No Pilot Light? Check the Igniter
Not all furnaces have a standing pilot light. Modern units often use an electronic ignition system. There’s no flame to light manually. Instead, an electric element glows hot to ignite the gas when the thermostat calls for heat.
