Goodman Furnace Pilot Light Troubleshooting and Relighting Guide

The Goodman furnace pilot light is a small but critical component that ensures continuous heating in many older furnaces. This guide explains how the pilot light works, common causes of failure, step-by-step relighting instructions, safety precautions, and when to call a professional. It emphasizes practical troubleshooting for homeowners while highlighting potential parts, costs, and long-term solutions.

Issue	Likely Cause	Quick Fix
Pilot Won’t Stay Lit	Faulty thermocouple or dirty pilot orifice	Clean pilot, replace thermocouple
No Pilot Flame	Gas supply off, clogged orifice	Check gas valve, relight pilot
Weak Flame	Clogged orifice or low gas pressure	Clean orifice, verify gas pressure
Clicking Or Humming	Faulty gas valve or control module	Inspect control assembly, call technician

How The Goodman Furnace Pilot Light Works

The pilot light is a small, continuously burning flame that ignites the main burners when the thermostat calls for heat. Goodman furnaces that use a standing pilot have a pilot assembly consisting of a pilot orifice, pilot tube, and thermocouple or flame sensor. When the pilot flame heats the thermocouple, the thermocouple generates a small voltage that keeps the gas valve open.

Key Components: pilot orifice, pilot tube, thermocouple (or electronic flame sensor), gas control valve, and pilot adjustment screw if present.

Common Pilot Light Problems And Causes

Pilot Light Won’t Stay Lit

This symptom often points to a failing thermocouple or flame sensor that no longer signals the gas valve to remain open. Soot or dirt on the pilot assembly can also prevent stable flame contact with the sensor.

Pilot Flame Is Weak Or Yellow

A healthy pilot flame is steady and blue. A yellow or lazy flame suggests a clogged pilot orifice, insufficient combustion air, or low gas pressure. Rust or debris can disrupt airflow and combustion.

Pilot Light Won’t Light At All

If attempts to light the pilot fail, the cause can be an interrupted gas supply, a closed gas valve, or a blocked pilot orifice. It may also be an ignition system issue on furnaces with electronic ignition.

Intermittent Pilot Light

Intermittent operation can come from loose wiring to the control board or thermocouple, a failing gas valve, or drafts in the furnace cabinet that extinguish the flame.

Safety First: Precautions Before Working On A Pilot Light

Turn Off Power And Gas: Before any inspection, turn off the furnace power at the breaker and set the gas control valve to the OFF position to prevent accidental ignition.

Ventilate The Area: If a smell of gas is present, leave the home immediately and call the gas company or emergency services. Do not operate electrical switches or create sparks.

Use Proper Tools: Use a long-reach lighter or match designed for pilot relighting and a flashlight to inspect components. Wear safety glasses and gloves to avoid injury.

Step-By-Step Relighting Procedure For Goodman Furnace Pilot Light

These steps apply to Goodman furnaces with a standing pilot. If the furnace uses electronic ignition, do not attempt manual relighting—refer to the manual or a technician.

1. Locate The Pilot Assembly And Gas Control Valve: The pilot assembly is near the burner chamber; the gas control valve will have OFF, PILOT, and ON positions.
2. Turn Off Power And Wait: Switch off the furnace electrical power and set the gas valve to OFF for at least five minutes to clear any residual gas.
3. Set To Pilot: After waiting, set the valve to PILOT. Press and hold the pilot knob down to allow gas flow to the pilot.
4. Light The Pilot: While holding the knob, use a long-reach lighter to ignite the pilot. Keep the knob depressed for 30–60 seconds to heat the thermocouple.
5. Release And Set To On: Slowly release the pilot knob. If the pilot stays lit, turn the valve to ON. Restore power to the furnace and verify normal operation.
6. If Pilot Does Not Stay Lit: Repeat lighting steps once. If the pilot fails to remain lit after two attempts, proceed to troubleshooting components.

Troubleshooting Steps If Relighting Fails

Check The Thermocouple

The thermocouple is a common failure point. Inspect for soot buildup, corrosion, or loose connections at the gas valve. A multimeter can test voltage output; a healthy thermocouple produces about 25–30 mV when heated.

Clean The Pilot Orifice

Turn off gas and power, remove the pilot orifice if accessible, and clear blockage with compressed air or a fine needle. Avoid enlarging the orifice or damaging threads.

Inspect Gas Supply And Valve

Verify the main gas valve is open and that other gas appliances operate normally. If gas pressure seems low, contact the utility. A faulty gas control valve will require replacement by a licensed technician.

Look For Drafts Or Obstructions

Check for drafts from dryer vents, open windows, or cracked furnace doors that could blow out the pilot. Also inspect the burner area for debris or insect nests that might interfere with the pilot flame.

Replacing Common Parts: Thermocouple, Pilot Orifice, And More

Thermocouple replacement is a common DIY repair for those comfortable with basic tools and turning off the gas. Use the exact replacement specified by Goodman to ensure proper length and thread size.

Pilot orifices are inexpensive but delicate. If the orifice is damaged or heavily clogged, replace it rather than attempting aggressive cleaning that could deform the opening.

Gas control valves should be replaced by a licensed HVAC technician due to safety and code considerations. Gas valve replacement often requires a permit and inspection depending on local regulations.

Costs And Time Estimates

Thermocouple: Parts cost $10–$40; DIY replacement time 15–45 minutes. Thermocouple replacement by a technician typically $75–$200 including labor.

Pilot Orifice Cleaning Or Replacement: Parts $5–$25; DIY cleaning 15–30 minutes. Replacement by a pro $80–$200 depending on access and diagnostics.

Gas Control Valve Replacement: Parts and labor $300–$900. Price varies by model and local labor rates.

When To Call A Professional

Call a licensed HVAC technician or gas service if the pilot will not stay lit after cleaning and thermocouple replacement, if the gas valve appears faulty, if there is a persistent gas odor, or if the homeowner is uncomfortable working with gas components.

Signs That Require Immediate Professional Attention: repeated pilot outages, visible gas leaks, unusual noises from the gas valve, yellow flame on main burners, or carbon monoxide alarm activation.

Preventive Maintenance To Keep The Pilot Light Reliable

• Schedule Annual Furnace Service: A professional inspection and tune-up reduces pilot-related failures and maintains efficiency.
• Keep The Area Clean: Prevent dust, cobwebs, and insect nests from building up near the pilot assembly and burners.
• Inspect The Venting: Ensure proper combustion air and exhaust venting to prevent flame instability and safety hazards.
• Replace Aging Components: Thermocouples and pilot assemblies wear out; proactive replacement can prevent winter breakdowns.

Electronic Ignition Versus Standing Pilot Systems

Many modern Goodman furnaces use electronic ignition systems (hot surface ignition or intermittent pilot) that do not have a constantly burning pilot light. These systems are more energy-efficient and reduce pilot-related maintenance but can still have ignition control failures that mimic pilot problems.

If the furnace lacks a standing pilot, the troubleshooting steps above do not apply, and the homeowner should consult the furnace manual or a technician for electronic ignition diagnostics.

Resources And Replacement Part Identification

Use the Goodman furnace model number, located on the furnace data plate, to order compatible replacement parts. Manufacturer manuals and parts diagrams help identify pilot assembly components and thermocouple specifications.

Official Goodman resources, HVAC suppliers, and licensed technicians are recommended sources for genuine parts. Local codes may require licensed installation for gas control replacements.

Frequently Asked Questions About Goodman Furnace Pilot Light

How Long Should A Pilot Light Burn?

A standing pilot is designed to run continuously. The flame should be steady and blue; any change indicates a problem needing inspection.

Can A Pilot Light Cause Carbon Monoxide?

A properly functioning pilot does not create carbon monoxide. However, poor combustion or blocked vents can lead to CO production. Install carbon monoxide detectors and have the furnace inspected if CO alarms sound.

Is It Safe To Relight The Pilot Myself?

Relighting is safe when following manufacturer instructions and safety precautions. If there is a gas smell, or if the furnace uses electronic ignition, do not relight and call a professional.

How Often Should Thermocouples Be Replaced?

Thermocouples can last many years but may fail after heavy use or exposure to soot and corrosion. Replace if the pilot won’t stay lit and cleaning does not help.

Useful Tips For Homeowners

Keep the furnace manual and pilot relighting instructions in an accessible place. Photograph component locations before disassembly to ease reassembly. Document any repairs and part numbers to simplify future maintenance.

Tip: If the pilot routinely goes out after a thermostat call, the problem may be in the control system rather than the pilot assembly; note patterns and communicate them to the technician.

Links And Further Reading

Refer to the Goodman furnace owner’s manual, local gas utility safety guides, and HVAC trade resources for additional diagnostic procedures and safety information. For part replacements and complex repairs, consult a licensed HVAC contractor.

Goodman Manufacturing Official Site • U.S. Consumer Product Safety Commission