The pilot light going out can leave a home without heat and create safety concerns. This article explains why a furnace pilot won’t stay lit, practical troubleshooting steps, safety precautions, cost estimates, and when to call a professional. The guidance covers standing pilot systems and common modern variations to help readers diagnose issues and decide next steps.
| Symptom | Likely Cause | Action |
|---|---|---|
| Pilot lights then goes out | Faulty thermocouple or dirty pilot | Clean pilot assembly or replace thermocouple |
| Pilot won’t ignite | No gas supply or clogged orifice | Check gas valve, clean orifice, call tech |
| Pilot stays weak | Drafts or low gas pressure | Check venting, inspect gas pressure |
Simple tasks—cleaning the pilot or replacing a thermocouple—are feasible for experienced DIYers comfortable working with gas appliances. Safety discipline and correct parts are essential.
Do not attempt to repair gas valves, main gas lines, or complex control systems without licensing. Incorrect work can void warranties and create severe hazards.
Signs That Indicate Replacement May Be Preferable
Repeated pilot issues, frequent part replacements, and an aging furnace nearing the end of its expected service life may justify replacement. Modern high-efficiency furnaces provide better reliability and lower operation costs.
Consider replacement if repair estimates approach 50% of a new unit’s installed cost, or if the furnace is over 15–20 years old and shows other signs of wear.
Key Takeaways For Homeowners
- Most common cause: thermocouple failure or pilot blockage.
- First steps: observe flame, check drafts, clean orifice, verify thermocouple alignment.
- Safety first: stop and call a professional if gas odor, valve issues, or uncertain repairs are present.
- Maintenance: annual service and carbon monoxide detectors improve safety and reliability.
Helpful Resources And Next Steps
Refer to the furnace manufacturer’s manual for model-specific pilot lighting and troubleshooting instructions. For persistent or complex issues, contact a licensed HVAC professional who can perform gas pressure testing, valve diagnostics, and safety checks.
Local utility companies often provide safety information and emergency support for suspected gas leaks. Keep emergency numbers handy and ensure household members know basic safety actions if a gas smell is detected.