The Basic Steps to Light Your Furnace Pilot Light
To light a furnace pilot light, you need to locate the pilot assembly (a small tube near the burner), set the gas control valve to "Pilot," hold down the ignition button while holding a lit match or lighter to the pilot opening, and keep the button pressed for 30 to 60 seconds after the flame catches. Once the pilot stays lit on its own, turn the gas control valve to "On" and listen for the main burner to ignite within a few seconds.
The exact location and appearance of your pilot assembly depends on your furnace model, so check your owner's manual first — it will show you where to find the pilot tube and which valve controls the pilot gas. If you cannot find the manual, search online for your furnace brand and model number (usually printed on a label inside the furnace cabinet).
Key Takeaways
- Set the gas control valve to "Pilot" before attempting to light anything, or you risk flooding the furnace with gas.
- You must hold the ignition button down continuously while lighting and for 30 to 60 seconds after the flame appears, or the pilot will go out when ready.
- If the pilot will not stay lit after three attempts, stop trying and call a technician — a faulty thermocouple or gas leak requires professional repair.
- Never use an electric lighter or lighter fluid near a furnace; use only a long-reach match or butane lighter designed for this purpose.
Locate the Pilot Assembly and Gas Control Valve
Open the furnace cabinet door and look for a small metal tube with an opening about the size of a pencil tip. This is the pilot tube. Near it you will find a round dial or knob labeled with settings like "Off," "Pilot," and "On" — this is your gas control valve. The ignition button is usually a red or black push-button located on the same assembly, or sometimes on the valve itself.
If the furnace is cold and has not run in a while, wait a few minutes before starting. This allows any residual gas to clear. Do not attempt to light the pilot if you smell gas strongly — turn off the gas at the main shutoff valve, open windows, and call your gas company or a technician.
Set the Valve to Pilot and Prepare to Ignite
Turn the gas control valve dial to the "Pilot" position. This reduces gas flow to only the pilot tube and prevents the main burner from flooding with gas while you work. Have your match or lighter ready before you proceed — you want to ignite the pilot within a few seconds of opening the gas.
Position yourself so you can see the pilot opening clearly and reach the ignition button comfortably. You will be holding the button down for up to a minute, so make sure you are in a stable position. If you are using a match, light it first; if you are using a lighter, have your thumb on the ignition button and your other hand holding the lighter near the pilot opening.
Hold the Button and Light the Pilot Flame
Press and hold the ignition button with one hand while bringing the lit match or lighter flame to the pilot opening with the other. You should see a small blue flame appear at the pilot tube within a few seconds. Keep holding the button down — do not release it yet.
Continue holding the button for 30 to 60 seconds after the flame appears. This allows the thermocouple (a heat-sensing device near the pilot) to warm up and signal the gas valve to stay open. If you release the button too soon, the pilot will go out when ready. After 60 seconds, slowly release the button while watching the flame. If it stays lit, you have succeeded.
Turn the Valve to On and Check the Main Burner
Once the pilot flame is holding steady on its own, turn the gas control valve from "Pilot" to "On." Within a few seconds, you should hear a soft click or whoosh as the main burner ignites. The burner flame should be blue with a small yellow tip at the base — if it is mostly yellow or orange, the burner may need cleaning, but the furnace will still heat.
Listen for the furnace fan to start after another 30 seconds or so. The fan will run for a few minutes to push warm air through your ducts. Once the fan is running, your furnace is operating normally and you can close the cabinet door.
What to Do If the Pilot Will Not Stay Lit
If the pilot flame goes out as soon as you release the button, the thermocouple is likely faulty and needs replacement. This is a common wear item but requires a technician to install. Do not keep trying to light it — repeated attempts waste gas and can create a safety hazard.
If you smell gas after lighting the pilot, or if the pilot lights but the main burner does not ignite within 10 seconds, turn the valve back to "Off" when ready and call a technician. These are signs of a gas leak or a problem with the ignition system that you should not attempt to fix yourself.
Safety Precautions and When to Call a Professional
Never force the gas control valve or ignition button — they should turn and press smoothly. If a valve is stuck or hard to move, stop and call a technician rather than risk breaking it. Do not use an electric lighter, lighter fluid, or any accelerant near the furnace. The pilot opening is designed for a straightforward flame, and anything else can damage the assembly or create a fire risk.
If you have tried to light the pilot three times and it will not stay lit, or if you are uncomfortable working near the furnace at all, call a heating technician. A service call usually costs between $100 and $200, but it is far safer than guessing. If your furnace is still under warranty, check whether the warranty covers pilot light service before you pay out of pocket.
Frequently Asked Questions
How long should I hold the ignition button down?
Hold it for 30 to 60 seconds after the flame appears. The thermocouple needs time to heat up and signal the valve to stay open. If you release it too soon, the pilot will go out. If you hold it longer, that is fine — just do not release it before 30 seconds have passed.
What does the pilot flame look like when it is working correctly?
A healthy pilot flame is small, blue, and steady — about the size of a match flame. It should not flicker or dance. If the flame is yellow or orange, the pilot tube may be dirty, but the furnace will still work. A flame that is very small or hard to see may indicate low gas pressure.
Can I light the pilot with an electric lighter?
No. Electric lighters can damage the pilot assembly and create a fire hazard. Use only a long-reach match or a butane lighter designed for lighting candles or grills. The flame needs to be a straightforward open flame, not a spark or hot coil.
Why does my pilot light keep going out after I turn the valve to On?
The thermocouple is probably failing. This device senses the pilot heat and tells the gas valve to stay open. When it wears out, the valve closes even though the pilot is lit. A technician can replace it in about an hour. Do not keep relighting it — call for service instead.
Is it safe to light the pilot myself, or should I always call a technician?
Lighting the pilot yourself is safe if you follow the steps and use common sense — no forcing valves, no accelerants, and no ignition attempts if you smell gas. If you are uncomfortable or the pilot will not stay lit after one or two tries, call a technician. It is not worth the worry.