To relight a furnace pilot light safely, turn the gas valve to "Off," wait five minutes for gas to clear, then turn the valve to "Pilot," press and hold the reset button while holding a long lighter to the pilot opening. Once the flame lights, keep holding the button for 60 seconds, then release and turn the valve to "On." If the flame goes out, wait five more minutes before trying again.
That's the short answer. The rest of this guide covers the exact tools you need, the mistakes that cause pilot lights to fail, and how to tell when a pilot problem is actually a sign of a bigger furnace issue. We've walked Pennsylvania homeowners through this hundreds of times, and the steps below are the same ones our technicians use.
What You Need Before You Start
Before you touch the furnace, gather these items. Having everything within reach means you won't be fumbling in the dark next to an open gas line.
- A long-barrel lighter or a fireplace match (a standard cigarette lighter is too short and puts your hand too close to the burner)
- A flashlight or headlamp
- A clean rag or small brush to wipe dust off the pilot assembly
- Your furnace's model number and manual, if you have it
- A carbon monoxide detector within 15 feet of the furnace
If you smell gas at any point - a rotten-egg odor, not just the faint whiff of a pilot - stop immediately. Leave the house, don't flip any switches, and call your gas utility's emergency line from outside. That's not a pilot problem. That's a gas leak.
Step-by-Step: How to Relight a Furnace Pilot Light Safely
These are the exact steps for a standard standing-pilot gas furnace. Most Pennsylvania homes built before 1990 have this type of system, though newer furnaces use electronic ignition and don't have a pilot at all.
- Turn the thermostat to "Off." Set it to the lowest temperature or switch it off entirely. You don't want the furnace trying to fire while you're working on it.
- Find the gas valve on the furnace. It's usually a red or black knob near the bottom of the unit with three positions: Off, Pilot, and On.
- Turn the valve to "Off" and wait five minutes. This clears any gas that may have accumulated. Five minutes is the minimum - don't rush it.
- Locate the pilot assembly. Look for a small metal tube near the burners with a tiny opening at the end. The reset button (sometimes labeled "Pilot" or "Reset") is usually nearby.
- Turn the valve to "Pilot." Press and hold the reset button down. You'll feel resistance - that's normal.
- Light the pilot. Hold your long lighter to the pilot opening while the button is pressed. The flame should light within a few seconds.
- Hold the button for 60 seconds. This lets the thermocouple heat up. If you release too early, the flame will go out.
- Release the button and turn the valve to "On." The pilot should stay lit. If it goes out, wait five minutes and repeat.
- Turn the thermostat back on. Set it to heat and listen for the burners to ignite. You should see a blue flame through the sight glass.
If your furnace has electronic ignition instead of a standing pilot, you won't see a pilot flame at all. Those systems use a hot surface igniter or spark igniter, and relighting isn't part of the process. If you're not sure which type you have, check the manual or look for a small window on the furnace - a standing pilot will have a visible flame.
For homeowners in older Pennsylvania homes with original gas furnaces, we often find pilot assemblies that haven't been cleaned in years. Dust and rust on the thermocouple can make relighting a losing battle. If you're dealing with a furnace that won't cooperate, our Gas Furnace Repair in Pennsylvania team can diagnose the issue same-day.
Why Does My Furnace Pilot Light Keep Going Out in Pennsylvania?
A pilot light that keeps going out in Pennsylvania is usually caused by a dirty thermocouple, a draft from a nearby window or door, or a gas pressure issue. Pennsylvania's older housing stock - especially in cities like Furnace Repair in Pittsburgh, Scranton, and Reading - has a lot of furnaces from the 1970s and 1980s where the thermocouple has simply worn out.
The thermocouple is a small metal rod that sits in the pilot flame. It generates a tiny electrical current that tells the gas valve "the pilot is lit, it's safe to send gas to the burners." When the thermocouple gets coated with carbon or rust, it can't generate enough current, and the gas valve shuts off. The pilot goes out. You relight it. It goes out again.
Other common causes include:
- Drafts. A pilot light is a small flame. A cold draft from a basement window or an open crawlspace door can blow it out. This is especially common in Pennsylvania winters when basement windows are cracked for ventilation.
- Dirty pilot orifice. The tiny opening where gas exits can get clogged with dust, spider webs, or rust. A clogged orifice means a weak flame that can't keep the thermocouple hot.
- Low gas pressure. If your gas pressure is below the furnace's requirement, the pilot flame will be too small to be reliable. This is a utility or regulator issue, not something you can fix yourself.
- Faulty gas valve. The valve itself can fail, sending inconsistent gas flow to the pilot. This is a repair, not a cleaning.
- High-efficiency furnace quirks. Some newer condensing furnaces have sensitive pressure switches that can trip and shut down the pilot. If you have a high-efficiency unit, our High-Efficiency Furnace Repair in Pennsylvania specialists can check the pressure switch and condensate lines.
If your pilot light keeps going out after you've relit it two or three times, stop trying. Something is failing, and repeated relighting won't fix it. That's when you call a technician.
Furnace Pilot Light Won't Stay Lit: Common Causes
When a pilot light won't stay lit, the problem is almost always one of four things: a bad thermocouple, a dirty pilot assembly, a draft, or a gas supply issue. Here's how to tell them apart.
Thermocouple Failure
This is the most common cause. A thermocouple costs $10-$20 at a hardware store, but replacing it requires shutting off the gas, disconnecting the old one, and installing the new one in the exact position. If you're not comfortable working with gas lines, this is a job for a pro. We replace thermocouples on Pennsylvania furnaces every week during heating season.
Dirty Pilot Assembly
If the pilot flame is yellow instead of blue, or if it's flickering and weak, the assembly is dirty. You can clean it with a small brush and compressed air, but be careful not to bend the thermocouple or enlarge the orifice. A gentle cleaning is fine. Aggressive scrubbing can damage the assembly.
Draft Issues
Check for open windows, doors, or vents near the furnace. In Pennsylvania basements, a cracked window is often the culprit. Close it and see if the pilot stays lit. If it does, you've found your problem.
Gas Supply Problems
If your other gas appliances (water heater, stove) are working fine, your gas supply is probably okay. If they're also struggling, call your gas utility. Low gas pressure is a utility issue, not a furnace issue.
If you've checked all four and the pilot still won't stay lit, the problem is likely inside the gas valve or the control board. That's a repair for a licensed technician. Our Furnace Repair in Pennsylvania team handles these diagnostics every day.
Common Mistakes to Avoid When Relighting a Pilot Light
Most pilot light injuries and furnace damage we see come from a handful of avoidable mistakes. Here's what not to do.
- Don't skip the five-minute wait. If you smell gas and light a match, you can cause a flash fire. Five minutes is not optional.
- Don't use a short lighter. A standard cigarette lighter puts your hand inches from the pilot opening. Use a long-barrel lighter or a fireplace match.
- Don't hold the reset button for less than 60 seconds. The thermocouple needs time to heat up. Release too early and the pilot will go out every time.
- Don't relight a pilot if the furnace is wet. Water around the furnace - from a leak, a flood, or condensation - can create a shock hazard. Dry it out first.
- Don't ignore a yellow flame. A healthy pilot flame is blue. Yellow means incomplete combustion, which produces carbon monoxide. If you see yellow, call a pro.
- Don't keep relighting a pilot that won't stay lit. After two or three attempts, stop. Something is broken.
One more thing: if your furnace is in a closet or tight space, make sure there's adequate ventilation before you start. Pilot lights need oxygen. A sealed closet with no air return can cause the pilot to burn poorly and produce carbon monoxide.
When to Call a Professional
Call a professional if you've relit the pilot twice and it won't stay lit, if you smell gas, if the pilot flame is yellow, or if you're not comfortable working around gas lines. Those are the four situations where DIY relighting becomes dangerous or pointless.
At Furnace Pros Pennsylvania, we handle pilot light issues, thermocouple replacements, gas valve repairs, and full furnace diagnostics. We serve homeowners across Pennsylvania, from Philadelphia and Pittsburgh to smaller towns like Lebanon and Chambersburg. If your furnace is older and you're tired of relighting the pilot every few weeks, we can also talk through whether a repair or a replacement makes more sense.
We also offer Furnace Maintenance in Pennsylvania that includes pilot assembly cleaning, thermocouple testing, and a full safety check. An annual tune-up is the best way to avoid mid-winter pilot failures.
Frequently Asked Questions
How do I relight my furnace pilot light safely in Pennsylvania?
Turn the gas valve to Off, wait five minutes, turn it to Pilot, press and hold the reset button while lighting the pilot with a long lighter. Hold the button for 60 seconds after the flame lights, then release and turn the valve to On. If it doesn't stay lit, wait five minutes and try again.
Why does my furnace pilot light keep going out in Pennsylvania?
The most common cause is a worn thermocouple, which costs $10-$20 but requires gas line work to replace. Other causes include drafts from basement windows, a dirty pilot orifice, or low gas pressure. If it goes out more than twice, call a technician.
Is it safe to relight a furnace pilot light myself in Pennsylvania?
Yes, if you follow the steps and don't smell gas. It's a routine task for homeowners. It becomes unsafe if you skip the five-minute wait, use a short lighter, or keep relighting a pilot that won't stay lit. When in doubt, call a pro.
What should I do if my furnace pilot light won't stay lit in Pennsylvania?
Check for drafts first - close any open windows or doors near the furnace. If that doesn't fix it, the thermocouple or pilot assembly likely needs replacement. After two failed attempts, stop and call a technician. Repeated relighting won't solve a mechanical failure.
When should I call a professional for furnace pilot light issues in Pennsylvania?
Call a pro if you smell gas, see a yellow pilot flame, have relit the pilot twice without success, or aren't comfortable working around gas. We handle pilot light repairs, thermocouple replacements, and full furnace diagnostics across Pennsylvania.
Get Help with Furnace Repair in Pennsylvania
If your pilot light won't stay lit or you'd rather not deal with it yourself, we're here to help. Our team serves homeowners across Pennsylvania with same-day furnace repair and honest, upfront pricing.
Call Furnace Pros Pennsylvania at (833) 586-3803 to schedule a visit. We'll diagnose the pilot issue, fix it right, and make sure your heat is back on before we leave.