Furnace Won't Ignite? Learn How to Easily Relight the Pilot Light
Is your house feeling chilly even though the thermostat is turned up? If your furnace isn't kicking on to produce heat, the issue is likely a pilot light that has gone out. Don't worry - in most cases you can easily relight the furnace pilot light yourself in just a few steps. With some basic safety precautions and following the proper relighting technique, you can have your furnace heating your home again in no time. We'll walk through everything you need to know about how to safely relight a furnace pilot light.
What is a Furnace Pilot Light?
Inside your gas furnace, there is a small flame called a pilot light that burns continuously. The pilot light's job is to ignite the main burner flame whenever the thermostat tells the furnace to turn on and start heating. This allows your furnace to operate without needing an ignition device to keep sparking a flame on and off.
The pilot light provides a ready flame to trigger the main gas burner, allowing heated air to start flowing through your home's ducts and vents. If the pilot light happens to blow out and go out, your furnace won't be able to produce any heat. Thankfully, the fix is usually simple - carefully relighting the dormant pilot.
Causes of a Furnace Pilot Light Going Out
There are a few common reasons that can cause a stable furnace pilot light to suddenly go out:
- A weak flame or slight blockage in the pilot tube resulting in an unstable flame
- Buildup of dirt, dust or debris around the pilot light assembly
- A problem with the thermocouple sensor that detects the pilot flame
- An issue with the gas valve or igniter that controls gas flow
- Improper gas line pressure or a drop in gas supply
- A furnace draft blowing out the pilot flame
While an underlying issue like a faulty thermocouple may need a professional HVAC technician to diagnose and fix, the pilot can often be relit successfully in the meantime. However, if it continues going out frequently, call for service to have it properly inspected.
Safety First When Relighting a Pilot
Before you get started with relighting the furnace pilot, safety should always come first. Make sure to take these precautions:
- Turn off both the electrical power and gas supply to the furnace. This prevents accidental ignitions.
- Allow adequate time for any accumulated gas to dissipate before relighting.
- Have an emergency extinguisher on hand in case a fire erupts.
- Work in a well-ventilated area to prevent gas buildup.
- If you smell leaking gas, leave the area immediately and call the gas company.
Relighting a pilot is usually a straight-forward process, but gas appliances can be dangerous if not handled properly. Always put safety first and exercise extreme caution when working with your furnace.
How to Relight Your Furnace Pilot
Once you've taken the proper safety steps, follow this complete guide to relight your furnace pilot light:
Locate the Pilot Light Assembly
Start by accessing the pilot light assembly, which is attached to the main gas burner. It's typically located at the bottom of the furnace near the main gas line. The pilot will have a small opening for the flame and a push-button ignition.
Look for a small metal tip that protrudes from the pilot assembly - this is the thermocouple sensor. Make sure not to bend it out of alignment when handling the pilot assembly.
Shut Off Power and Gas Supply
Find the furnace power switch and turn it completely to the "Off" position. There may also be a separate power switch for just the burner/pilot assembly.
Next, locate the main manual gas shut-off valve on the supply line leading to the furnace. Turn the valve clockwise to the fully closed position to cut off gas flow.
Allow Time for Gas to Dissipate
Wait at least 5 minutes after shutting off the gas to allow any built up gas fumes to dissipate. This will prevent an explosion risk when relighting.
Check around the furnace and pilot area to ensure no gas odor remains before moving to the next step. The area should smell clean.
Set Pilot Control to "Pilot"
Look for the pilot control switch on the gas valve or burner assembly. Turn or slide the switch to the "Pilot" position. This prepares the valve to allow gas to flow only to the pilot when lit.
Light Pilot Flame
Insert a long match or igniter wand into the pilot light opening. Press the reset button on the pilot assembly all the way in and hold it there.
While holding the reset button, ignite your match and hold the flame to the pilot opening. Continue holding the button for 60-90 seconds after the pilot is lit, then release the reset button.
Observe the Pilot
Watch the pilot flame closely once released. The flame should burn clean and steady, with a blue color rather than yellow. If it goes out, repeat the process to relight it.
If the flame repeatedly goes out after releasing the reset button, the thermocouple likely needs cleaning or alignment. Or there may be an issue with gas supply.
Set Gas Valve to "On"
Once the pilot flame remains lit and stable after releasing the reset button, turn the gas valve control switch to the "On" position. This will allow gas to flow to both the pilot and the main burner as needed.
Restore electrical power to the furnace so it can resume normal operation and ignite the main flame when heat is called for.
Troubleshooting Pilot Light Problems
If you're having difficulty getting your pilot relit after several tries, here are some troubleshooting tips:
- Won't light: Check that gas is reaching the pilot assembly. Try cleaning any dirt or debris blocking the pilot nozzle. Ensure ignition source is producing a strong spark.
- Won't stay lit: Clean thermocouple tip using emery cloth. Adjust tilt so it engulfs pilot flame. Replace thermocouple if corroded.
- Repeatedly goes out: Check for furnace drafts blowing out flame. May need to seal gaps allowing air leaks.
- Weak flame: Verify adequate gas line pressure. Remove blockages/kinks in pilot tube.
Professional Pilot Light Repair
If you are at all unsure about safely relighting your furnace pilot, or have attempted to relight it unsuccessfully several times, call a professional HVAC technician. It's better to be safe than sorry when dealing with gas appliances.
A technician can use diagnostics to determine the exact cause of a stubborn pilot light problem. They have specialized tools and training for handling tricky pilot assembly repairs and full-system troubleshooting.
Preventing Future Furnace Pilot Problems
To help keep your pilot lit and avoid repeated outages, follow these maintenance practices:
- Clean the pilot assembly tube annually to remove mineral deposits.
- Check for any furnace drafts letting in air - seal gaps if found.
- Replace old or corroded thermocouples when needed.
- Have an HVAC professional inspect your system before each heating season.
Routine maintenance and quick response to any pilot issues can keep your furnace running reliably all winter long. Just remember the proper safety steps whenever relighting the furnace pilot yourself.
Knowing how to safely relight your furnace pilot light is an important home maintenance skill that can save time and money. Follow these key steps:
- Turn off electrical and gas supply to furnace
- Wait 5 minutes for gas dissipation
- Set pilot control to "Pilot" position
- Depress reset button and light match to pilot opening
- Hold reset for 60-90 seconds until pilot stays lit
- Watch for stable flame then set gas valve to "On"
- Restore power to furnace
Relighting your pilot should be painless with proper precautions. But don't continue attempting to relight it indefinitely without calling for professional service. Safety always comes first when dealing with gas appliances. By following these guidelines, your furnace pilot should be burning brightly to keep your home warm and comfortable all season long.