Relighting a pilot light on a furnace is a common maintenance task for older homes with gas furnaces. When the flame goes out, you may notice cold spots, uneven heating, or a chilly basement. While many relighting steps are straightforward, working with gas appliances requires caution to prevent leaks and carbon monoxide exposure. This guide explains how to determine whether you have a standing-pilot or an electronic ignition, gather the right tools, and perform a relight procedure. It also covers troubleshooting, safety precautions, and signs you should call a professional.
Safety First When Relighting A Pilot Light
Safety is the top priority when relighting a pilot light. Gas leaks or a malfunctioning vent can cause serious harm, so proceed only if the space is ventilated and free of obvious gas smells. If you detect gas, evacuate immediately and call your gas utility or emergency services from outside the home.
Never operate electrical switches or create sparks near a furnace if you suspect a gas leak. Keep children and pets away from the area during the relighting process. Use a long-reach lighter or a long match, and never abandon the area while the flame is not securely established around the pilot.
Always verify that CO detectors are working and that the furnace area has adequate ventilation. If any step feels uncertain, or if you notice persistent issues such as a yellow flame or a flickering pilot, stop and seek professional help.
Is Your Furnace Standing-Pilot Or Electronic Ignition?
Most older models use a standing pilot light that must be manually lit when the flame goes out. Newer furnaces often employ an electronic ignition system and do not use a continuously burning pilot. For these units, relighting a traditional pilot is not applicable; follow the manufacturer’s instructions or contact a professional for service.
Before attempting any relight, identify the furnace type by inspecting the control panel and pilot assembly. Look for labels that indicate “Pilot,” “On,” and “Off” for standing-pilot systems, or a spark/ignition symbol for electronic systems. If in doubt, consult the user manual or a licensed technician to avoid improper operation.
Tools And Preparations
Gathering the right tools and ensuring a safe environment will make the relighting process smoother. Clear the area around the furnace to allow easy access and ventilation. Have a flashlight ready to inspect the pilot area in low light.
- Long-reach lighter or long match for lighting the pilot
- Safety glasses and non-slip gloves
- Flashlight or headlamp for visibility
- Smoke and carbon monoxide detectors in working order
- Soft cloth to wipe away any dust around the pilot area
With the tools at hand, confirm there is no strong gas odor and that doors or windows are open or a vent is available for fresh air. Read the furnace’s label or manual for specific steps related to your model, as instructions can vary slightly between manufacturers.
Step-By-Step Relighting Process For Standing-Pilot Furnaces
- Turn the thermostat to Off and set the furnace switch or breaker to Off to ensure no ignition occurs during setup.
- Locate the gas control valve on the furnace. Move the knob to the Off position and wait five minutes to purge any accumulated gas fumes.
- Turn the knob to the Pilot position. Press and hold the reset or ignition button if your model requires it, while keeping the valve depressed.
- Ignite the pilot flame with a long-reach lighter or long match at the pilot opening. Hold the flame until the pilot stays lit, usually about 30 to 60 seconds, then release the button slowly.
- Keep the pilot flame steadily burning, then resume gas flow by turning the knob to On and reactivating the furnace switch. Set the thermostat to your desired temperature.
- Observe the main burner after ignition. If the flame remains stable for several minutes, the system is functioning. If the pilot goes out, repeat the steps once more or consult a professional if it continues to fail.
During the process, never stand directly over the pilot opening and avoid leaning over the furnace. If any step produces a strong gas odor or the flame won’t light, stop immediately.
Troubleshooting Common Issues
Certain symptoms during relighting can point to specific issues. The following quick guide helps homeowners diagnose and respond to common problems.
| Symptom | Possible Cause | Recommended Action |
|---|---|---|
| PILOT LIGHT LIGHTS BUT SHUTS OFF SOON AFTER | Weak or dirty thermocouple; insufficient gas pressure | Relight with clean pilot area; if problem persists, inspect or replace faulty thermocouple; contact a professional for gas pressure testing |
| FLAME IS YELLOW OR FLICKERS | Dirty burner or improper gas-air mix | Turn off, clean or service the burner, ensure proper gas supply, and seek professional help if it recurs |
| FLAME DOES NOT STAY LIT AFTER HOLDING | Thermocouple not heated long enough; draft near pilot | Hold down time longer during relight; check for drafts and seal openings; replace thermocouple if necessary |
| NO GAS SMELL AND PILOT DOES NOT IGNITE | Gas valve or line issue; safety shutoff | Do not force; call the gas company or a licensed technician for inspection |
If any table entry describes persistent issues, do not continue attempts. Persistent ignition problems can indicate gas supply issues, valve failures, or ignition system malfunctions that require professional service for safety.
When To Call A Professional
Professional help is advisable in several scenarios. If there is a persistent gas odor, a yellow-tlickering flame, or repeated pilot outages, do not attempt further relighting. A technician can check gas pressure, inspect the thermocouple and ignition system, and identify leaks or venting problems.
- Gas smell, hissing, or suspected leak
- Pilot flame extinguishes after lighting and cannot be relit safely
- Repeated pilot outages, especially after maintenance tasks
- Unfamiliar furnace model or uncertain ignition method
Also consider scheduling annual furnace maintenance with a licensed HVAC technician. Regular inspections help maintain efficiency, improve safety, and extend equipment life.
Maintenance After Relight
After a successful relight, take steps to keep the system reliable. Ensure the flame is blue with a steady, quiet burn, and avoid yellow tips. Confirm that vents and flues are clear of debris and that the area remains well-ventilated.
Replace or clean filters as recommended by the manufacturer, which can improve combustion efficiency. Check CO detectors and test alarms monthly. Note the date of the relight and plan a professional inspection within the following year or per your local code requirements.
In summary, safely relighting a standing-pilot furnace involves careful preparation, correct identification of the furnace type, and cautious execution. When in doubt, or if ignition issues persist, a licensed HVAC technician should be consulted to ensure safe operation and long-term reliability.