Available 24/7

10 Fast Facts About Your Furnace Pilot Light (Updated 2025)

furnace pilot light

Originally published on October 5, 2023. Updated in January 2025 to reflect the latest advancements in HVAC and AC technology, efficiency standards, and installation practices.

Meyer Heating & Air: Expert Heating System Repairs & Maintenance in St. Louis

Your furnace pilot light plays a crucial role in keeping your home warm during colder months. If you’ve ever experienced issues with your gas furnace ignition, knowing how to troubleshoot common problems can help you determine when it’s time to call an HVAC professional.

Keep reading to learn 10 essential facts about your pilot light, including troubleshooting tips, safety precautions, and when to seek professional St. Louis HVAC repair services.

1. What Is a Furnace Pilot Light?

A pilot light is a small flame that ignites the gas burner in older gas furnaces. This flame must remain lit for the furnace to function properly. However, modern furnaces now use electronic ignition systems instead of a continuous pilot light.

Types of Gas Furnace Ignition Systems:

Standing Pilot Light – Always stays lit and requires manual relighting if it goes out.
Intermittent Pilot Light – Ignites only when the furnace calls for heat.
Hot Surface Ignition – Uses an electric heating element to ignite gas burners.

📞 Need help with your furnace ignition? Call Meyer Heating & Air at (314) 845-1929 for expert service!

2. Does Your Furnace Have a Pilot Light?

If your furnace was installed after the 1980s, it likely has an electric ignition system rather than a conventional pilot light. If you’re unsure, check your owner’s manual or call a St. Louis HVAC technician for guidance.

3. Common Reasons Your Pilot Light Goes Out

Drafts or airflow disruptions – Open windows or vents near the furnace can blow out the flame.
Thermocouple failure – A faulty thermocouple will shut off the gas supply, preventing the pilot from staying lit.
Dirty or clogged pilot orifice – Debris buildup can block gas flow.
Gas supply issues – A malfunctioning gas valve or a disruption in service can prevent ignition.

🔧 Tip: If your pilot light frequently goes out, a technician may need to clean or adjust the thermocouple.

4. How to Relight Your Furnace Pilot Light

Step-by-Step Guide:

  1. Turn off the furnace – Locate the gas control knob and set it to OFF. Wait 5 minutes to allow any lingering gas to dissipate.
  2. Find the reset button – This is usually located near the gas control valve.
  3. Turn the gas knob to “PILOT” – Hold it down while using a long lighter to ignite the pilot flame.
  4. Hold for 30-60 seconds – Keep the gas knob pressed for about a minute to allow the thermocouple to warm up.
  5. Turn the knob to “ON” – Once the pilot flame is stable, turn the knob back to the ON position.

Important Safety Tip: If the pilot light doesn’t stay lit after multiple attempts, do not force itcontact a professional immediately.

5. If You Smell Gas, Take Immediate Action

Natural gas leaks are dangerous and require urgent attention. If you detect a rotten egg or sulfur smell, follow these steps:

  • Do NOT relight the pilot light.
  • Avoid open flames and electrical switches.
  • Evacuate your home immediately.
  • Call your gas company or 911 from outside your home.

📞 Concerned about a gas leak? Contact Meyer Heating & Air for an emergency inspection.

6. What Color Should the Pilot Flame Be?

A healthy pilot light should burn blue. If it appears yellow, orange, or flickering, this could indicate:

Incomplete combustion – Possible gas mixture issue.
Dirt buildup – Requires cleaning or adjustment.
Carbon monoxide risk – Seek professional furnace repair immediately.

7. The Role of a Thermocouple in Your Furnace

The thermocouple is a critical safety component that detects whether the pilot light is burning. If the flame goes out, the thermocouple automatically shuts off the gas supply to prevent leaks.

Signs of a Bad Thermocouple:
✔ Pilot light won’t stay lit.
✔ Furnace frequently shuts off.
✔ Requires multiple attempts to ignite.

8. Regular Maintenance Extends Furnace Lifespan

To keep your furnace pilot light and gas ignition system working efficiently, schedule annual maintenance with a trusted HVAC provider.

Meyer Heating & Air offers:

  • Pilot light cleaning and adjustments.
  • Thermocouple testing and replacement.
  • Full furnace inspections to prevent costly breakdowns.

9. Other Home Appliances That Use Pilot Lights

Pilot lights or electric ignitions are also found in:
Gas water heaters
Gas fireplaces
Gas ovens and stoves

Regular HVAC maintenance can prevent malfunctions in these appliances as well.

10. When to Call a Professional for Furnace Repairs

If your pilot light won’t stay lit or your heating system won’t turn on, professional repair may be needed. Meyer Heating & Air specializes in furnace repair and replacement throughout St. Louis.

📅 Schedule an appointment today:
📞 Call (314) 845-1929 or book online to restore your home’s heating!

Final Thoughts

Understanding your furnace pilot light can help you troubleshoot small issues before they become major problems. However, gas appliances require expert care to ensure safety. If you’re experiencing pilot light issues, trust the professionals at Meyer Heating & Air for reliable, 24/7 HVAC service.