Do I Need to Light My Furnace Pilot Light

The pilot light question is common for homeowners with older gas furnaces. This article explains what a pilot light does, when it must be lit, safe lighting steps, troubleshooting tips, and modern alternatives so readers can make informed decisions about their heating system. Key takeaway: Many newer furnaces do not require a standing pilot light; older systems often do, but safety and specific model requirements determine whether manual lighting is necessary.

Situation	Does The Pilot Need Lighting?	Action
No Heat And No Ignition	Yes, If Furnace Has Standing Pilot	Follow Safe Lighting Steps Or Call A Technician
Intermittent Ignition	Maybe	Troubleshoot Thermocouple, Gas Valve, Or Draft Issues
Electronic Ignition System	No	Check Power Or Control Board Instead

How A Furnace Pilot Light Works

A pilot light is a small, continuously burning flame that ignites the main gas burner when the thermostat calls for heat. Older furnaces use a standing pilot that stays lit 24/7, while many modern units use intermittent pilot or electronic ignition systems that only create a spark or flame when needed.

The pilot assembly includes a pilot burner, a thermocouple or thermopile sensing device, and a gas valve. The thermocouple detects heat from the pilot and signals the gas valve to stay open; if the pilot flame goes out, the thermocouple cools and closes the valve for safety.

Types Of Furnace Ignition Systems

Understanding the ignition type clarifies whether lighting a pilot is necessary. Common types include:

• Standing Pilot: Constant flame; manual lighting may be needed after outages or maintenance.
• Intermittent Pilot (IP): Pilot lights only when a heat call occurs; may use a small glow or electric spark to ignite the pilot then main burner.
• Hot Surface Ignition (HSI): Uses an electric element that glows hot to ignite gas; no pilot light required.
• Direct Spark Ignition: Uses an electrode to create a spark; pilot light is not used.

Knowing the furnace model and manual helps determine the ignition type and whether the pilot should be lit manually.

Do Older Furnaces Require Manual Pilot Lighting?

Many older residential furnaces with standing pilots require manual lighting after fuel interruptions or maintenance. If the pilot is out and the furnace has a standing pilot design, the homeowner typically needs to light the pilot to restore heating.

However, not all pilot outages require manual lighting. Some systems feature automatic relighting mechanisms or an intermittent pilot that re-ignites when the thermostat calls for heat. Review the furnace owner’s manual or model label to confirm the correct procedure.

Safety First: Is It Safe To Light A Pilot Yourself?

Lighting a pilot can be safe when performed correctly and when there are no signs of a gas leak or damage. Before attempting, verify there is no smell of gas, ensure proper ventilation, and follow the manufacturer’s instructions. If there is any doubt, contact a licensed HVAC technician or gas utility.

Warning signs that require professional help include persistent gas odor, corrosion on gas lines, repeatedly extinguished pilot, visible flames escaping the burner chamber, or an unfamiliar hissing sound from the gas valve.

Step-By-Step: How To Light A Furnace Pilot Safely

Use this general process only for furnaces with a standing pilot that the manual indicates can be lit by the homeowner. If the manual advises against DIY lighting, call a pro.

1. Turn Off Gas Control: Set the gas control knob to “Off” and wait five to ten minutes for residual gas to clear from the area.
2. Locate The Pilot: Open access panel and find the pilot assembly and control knob labeled “Pilot” or “Ignition.”
3. Set To Pilot: Turn the control to “Pilot,” press and hold the knob while using a long lighter or match to light the pilot.
4. Hold The Knob: Keep the control depressed for 30–60 seconds to allow the thermocouple to heat and signal the gas valve to stay open.
5. Release And Check: Slowly release the knob. If the pilot remains lit, turn the control to “On.” Replace panels and restore thermostat settings.

Always follow the specific timing and procedure in the furnace manual as some models require longer or shorter intervals.

Troubleshooting When The Pilot Won’t Stay Lit

If the pilot lights but goes out shortly after releasing the knob, common causes include a faulty thermocouple, a misaligned pilot flame, or a problem with the gas valve.

A weak pilot flame may indicate a clogged pilot orifice or insufficient gas pressure. Cleaning the pilot orifice carefully with compressed air or replacing the thermocouple often resolves the issue, but replacement parts should match the furnace specifications.

Why The Pilot Keeps Going Out: Common Causes And Fixes

Frequent pilot outages often stem from: faulty thermocouple, draft pulling the flame away, dirty orifice, pilot flame misalignment, or a failing gas control valve. Each cause has a preferred fix.

• Thermocouple Failure: Replace the thermocouple with the correct part number.
• Drafts: Seal access panels, check flue/chimney for blockages, and ensure adequate combustion air supply.
• Dirty Pilot Orifice: Clean or replace the orifice per manufacturer guidance.
• Gas Pressure Issues: Have a qualified technician measure and adjust gas pressure.
• Age/Wear: Consider replacing the furnace or converting to electronic ignition for reliability and efficiency.

When Not To Light The Pilot — Call A Professional

Do not attempt lighting and troubleshooting when there is a strong gas odor, suspected leak, damaged piping, or after major furnace repairs. Also avoid DIY efforts if the furnace manual advises that ignition requires a qualified technician or special tools.

If the pilot repeatedly fails after basic checks, persistent outages indicate an underlying component failure or venting problem requiring a licensed HVAC technician to diagnose and repair safely.

Alternatives To Standing Pilot Lights

Many homeowners upgrade to furnaces with electronic ignition systems to eliminate the constant pilot flame. Benefits include improved energy efficiency, lower gas use, reduced pilot-related maintenance, and often quieter operation.

Conversion options include replacing the furnace with an HSI or direct spark unit, or retrofitting certain systems when feasible. A professional can evaluate whether conversion is cost-effective based on system age and local energy costs.

Maintenance Tips To Avoid Pilot Problems

Regular maintenance reduces pilot failures and improves furnace reliability. Recommended tasks include annual professional inspection, cleaning the pilot orifice, checking and replacing the thermocouple if weak, and ensuring proper venting and combustion air supply.

Homeowners should also keep the furnace area clear of debris, avoid storing items near the furnace that could interfere with airflow, and test carbon monoxide detectors regularly when any gas appliance is present.

Cost Considerations: DIY Vs Professional Service

Simple pilot relighting often costs nothing beyond homeowner time. Replacing a thermocouple is a low-cost part but may require a technician for safe installation depending on local codes and comfort level.

Major repairs, gas valve replacements, or furnace replacement are more costly but can improve efficiency. A professional diagnosis can provide cost estimates and safety assurances. In some regions, utility companies offer rebates for upgrading to high-efficiency furnaces.

Common Questions About Lighting Furnace Pilots

Can A Pilot Be Relit After A Power Outage?

Yes, if the furnace uses a standing pilot, the pilot may need to be relit after a power outage depending on whether the pilot went out and how the ignition system operates.

How Often Should The Pilot Be Checked?

Checking the pilot monthly during the heating season is a reasonable homeowner habit; schedule an annual professional inspection to clean and tune the system before winter.

Does A Standing Pilot Waste Much Gas?

A standing pilot consumes a small continuous amount of gas, which adds up over time. Electronic ignition systems eliminate this continuous use and can reduce annual fuel costs.

When To Consider Replacing The Furnace

Frequent pilot or ignition problems, high repair bills, poor efficiency, or an aging furnace (typically 15–20+ years) suggests evaluating replacement. Newer high-efficiency furnaces use electronic ignition and provide better fuel economy and reliability.

Replacement decisions should factor in energy savings, repair frequency, indoor comfort, safety, and available incentives for upgrading to energy-efficient models.

Resources And Next Steps

Owners should consult the furnace owner’s manual and local utility safety resources for model-specific guidance. When in doubt, schedule a licensed HVAC technician for inspection, pilot relighting, or system upgrades. Safety and compliance with local codes are essential.

Practical next steps: identify your furnace model, read the manual, check for gas smells before attempting relighting, and call a professional for persistent issues or if the unit lacks homeowner-serviceable instructions.