If your furnace stopped producing heat, one of the first things to check is the pilot light. On older gas furnaces, a small flame called the pilot light burns continuously and ignites the main burner whenever the thermostat calls for heat. When that flame goes out, the furnace has no way to light the gas, and your system stops heating entirely.
This guide walks you through what the pilot light does, why it goes out, how to relight it safely, and when the problem is bigger than a simple relight.
What Is a Furnace Pilot Light?
A pilot light is a small, continuously burning gas flame located inside your furnace near the main burner. Its job is to ignite the main burner when the thermostat calls for heat. Most furnaces built before the mid-1990s use a standing pilot light. Newer furnaces typically use an electronic ignition system instead, so they do not have a pilot light at all.
If your furnace is a newer model and is not producing heat, the issue is likely with the electronic igniter rather than a pilot light. Our furnace repair team can diagnose either type.
Is Your Pilot Light Out? Here Is How to Check
On most older furnaces, you can see the pilot light through a small viewing window on the front of the unit. If you do not see a small blue flame burning near the burner assembly, the pilot light is out.
A healthy pilot light burns blue. If you see a yellow or orange flame, that is a sign of incomplete combustion, which can indicate a dirty or misaligned pilot orifice or a problem with the gas-to-air mixture. A yellow or orange pilot flame should be evaluated by a technician.
Why Does a Furnace Pilot Light Go Out?
A Gust of Air or Draft
The most common and least serious cause. A strong draft from a nearby vent, window, or even from the furnace door being opened and closed can extinguish the pilot flame. If the light goes out once and stays lit after you relight it, a draft was likely the culprit.
A Dirty or Clogged Pilot Orifice
Dust and debris accumulate inside furnaces over time. The small opening through which gas flows to feed the pilot flame can partially clog, reducing gas flow to the point where the flame becomes unstable or goes out. A dirty orifice often produces a weak or flickering flame even after relighting.
A Faulty Thermocouple
The thermocouple is a safety device positioned next to the pilot flame. It generates a small electrical signal that tells the gas valve to stay open as long as the pilot is lit. If the pilot goes out, the thermocouple stops sending that signal and the gas valve closes automatically, preventing unburned gas from entering your home.
When a thermocouple wears out or becomes misaligned, it may not generate a strong enough signal even when the pilot is burning normally. This causes the gas valve to shut down, and the pilot goes out shortly after you relight it. A pilot light that keeps going out within a minute or two of relighting is the classic symptom of a failing thermocouple.
Thermocouple replacement is an inexpensive repair that a technician can typically handle in a single visit.
A Problem With the Gas Supply
If there is no gas reaching the furnace at all, the pilot will not light regardless of what you do. Before troubleshooting the furnace itself, confirm that your other gas appliances, such as the water heater or gas range, are working normally. If none of your gas appliances are working, contact your gas provider. If only the furnace is affected, the issue may be with the furnace’s gas valve.
A Failing Gas Valve
The gas valve controls the flow of gas to both the pilot and the main burner. A valve that is failing or sticking may not allow enough gas through to maintain the pilot flame. Gas valve replacement is a job for a licensed technician.
How to Relight a Furnace Pilot Light
If your pilot light is simply out and there are no signs of a gas smell or other problems, you can safely attempt to relight it yourself. Always read the specific instructions on the label on your furnace first, as the exact steps vary by model.
General steps:
- Turn the furnace’s control knob to the “Off” position and wait at least five minutes. This allows any accumulated gas to dissipate before you introduce a flame.
- While waiting, check for any smell of gas near the furnace. If you smell gas, do not attempt to relight the pilot. Leave the house, leave the door open, and call your gas provider and emergency services from outside.
- After waiting, turn the knob to the “Pilot” position.
- Press and hold the reset button or the control knob itself (depending on your furnace model) to allow gas to flow to the pilot orifice.
- While holding the button, hold a lit long match or a long-reach lighter to the pilot orifice. The pilot should light.
- Continue holding the reset button for 30 to 60 seconds after the flame ignites. This gives the thermocouple time to heat up and generate the signal that tells the gas valve to stay open.
- Slowly release the button. If the flame stays lit, turn the control knob to the “On” position and set your thermostat above the current room temperature to test whether the main burner ignites.
If the flame goes out when you release the button, wait a few minutes and try again. If it goes out repeatedly after several attempts, the problem is most likely a faulty thermocouple or a gas supply issue, and it is time to call a professional.
When to Call a Professional for Furnace Pilot Light Repair
Call a technician if any of the following apply:
- You smell gas near the furnace at any point
- The pilot will not stay lit after two or three relighting attempts
- The pilot flame is yellow or orange rather than blue
- The pilot lights but the main burner does not ignite
- The furnace is making unusual noises (popping, banging, or rattling) when it tries to fire
- You have an older furnace and are not comfortable working near the gas components
Southern Air’s furnace repair team serves the Baton Rouge area and handles everything from thermocouple replacements to full heater installations. We provide upfront pricing before any work begins.
Should You Repair or Replace Your Furnace?
Baton Rouge winters are mild compared to most of the country, but when temperatures drop, your heating system needs to work. If your furnace is older than 15 years and has needed repeated repairs, it may be time to think about replacement rather than continuing to service an aging system.
A modern heat pump is often the smarter investment for South Louisiana homes. Heat pumps cool in summer and heat in winter using a single system, and they perform extremely well in mild climates like Baton Rouge’s where temperatures rarely stay below freezing for extended periods.
If you are unsure whether to repair or replace, our team can evaluate your current system and give you an honest recommendation based on its age, condition, and repair history.
Keeping Your Furnace Running Well
The best way to avoid pilot light problems and other furnace issues is regular maintenance. Annual tune-ups allow a technician to clean the pilot orifice, inspect the thermocouple, check gas pressure, and test all safety controls before the heating season starts.
Our Shield of Protection membership plan includes seasonal HVAC tune-ups, priority scheduling, and 20% off repairs, so you are covered if something does come up during the winter months.
Ready to Schedule a Furnace Repair in Baton Rouge?
Southern Air has been serving the Baton Rouge area since 1984. Whether your pilot light needs a simple relight and inspection or a component needs to be replaced, our licensed technicians will diagnose the problem clearly and fix it right.
Call us at (225) 217-6224 or schedule online to book a furnace repair visit today.
