Goodman Furnace H6 Error Code: Causes and Effective Fixes

The Goodman Furnace H6 Error Code signals an ignition or flame failure issue that prevents the heating system from operating safely. This article explains what the H6 Error Code means, common causes, step-by-step diagnostics, safe fixes, preventive maintenance tips, and when to call a professional. It aims to help U.S. homeowners and technicians quickly identify and resolve the fault while emphasizing safety and proper procedures.

Item	Quick Summary
Code Meaning	Ignition/Flame Failure — no flame detected during ignition attempts
Common Causes	Dirty ignitor, faulty flame sensor, gas supply issue, control board, wiring
Basic Checks	Power and thermostat, error LED sequence, gas valve, flame sensor cleaning
When To Call Pro	Smell of gas, persistent H6 after basic fixes, internal gas valve/control board problems

What The H6 Error Code Means

The H6 Error Code on Goodman furnaces is a diagnostic indicator for ignition or flame sensing failure during the startup sequence. The control board attempts to ignite the burners; if ignition does not occur or the flame sensor does not detect a stable flame within a preset time, the board records H6 and locks out further attempts to protect the system.

The code is designed to prevent dangerous conditions like unburned gas accumulation and repeated ignition attempts. Interpreting the H6 properly requires reading the furnace LED flash pattern and consulting the specific Goodman model’s service manual because LED patterns can vary by control board version.

Common Causes Of H6 Error Code Goodman Furnace

Ignitor Problems

A cracked, weak, or misaligned ignitor (hot surface or spark) is a frequent cause of ignition failure. Ignitors degrade over time and become less effective, leading to no ignition or intermittent ignition that triggers H6.

Flame Sensor Issues

A dirty or failing flame sensor will not register the flame even when burners light. Oil, dust, or oxidation on the sensor rod interferes with its ability to sense flame rectification, causing the control board to interpret no flame and set H6.

Gas Supply Or Valve Problems

Insufficient gas pressure, a closed gas shutoff valve, or a malfunctioning gas valve can prevent burners from lighting. Pilotless furnaces rely on the main gas valve opening; any obstruction or failure in that flow leads to ignition failure.

Control Board Or Wiring Faults

Defective control boards, relays, or damaged wiring between the board, ignitor, flame sensor, or gas valve can interrupt signals or power needed for ignition. Loose connectors or shorted wires are common electrical causes.

Airflow Or Pressure Switch Problems

A blocked vent, dirty filter, or failed pressure switch can prevent the furnace from completing safety checks for ignition. The board may block ignition if venting or induced draft conditions are inadequate.

Safety First: Precautions Before Troubleshooting

Always prioritize safety when diagnosing H6. Turn off electrical power at the furnace switch or breaker and shut off the gas if any gas odor is present. If a gas leak is suspected, evacuate and call the gas utility or emergency services.

Only qualified technicians should handle internal gas valve or control board replacements. Homeowners may perform basic visual checks and cleaning tasks if comfortable and following the manufacturer instructions.

Step-By-Step Diagnostic Checklist

1. Verify Error Code And LED Pattern: Reset the furnace, observe LED flashes to confirm H6. Record the pattern and cross-check the model’s service manual.
2. Check Thermostat And Power: Ensure thermostat calls for heat and the furnace has 120V power. Replace thermostat batteries and verify wiring if needed.
3. Inspect Air Filter And Vents: Replace dirty filters and clear blocked supply/return vents. Restricted airflow can indirectly cause ignition problems.
4. Listen For Inducer And Ignition Attempts: On a heat call, verify the inducer motor runs and the ignitor glows or the spark ignites. No inducer operation indicates a broader control or motor issue.
5. Smell For Gas: If gas odor exists, stop and call professionals. Do not attempt internal repairs.
6. Check Gas Supply And Valve: Confirm gas valves are open and other gas appliances are operating. Use a manometer if available to check gas pressure to the furnace.
7. Inspect Ignitor: Visually inspect for cracks or erosion. Test continuity or resistance per the service manual. Replace if damaged or outside spec.
8. Clean Flame Sensor: Remove and gently clean with fine abrasive (steel wool or emery cloth), then reinstall securely. Cleaning often resolves false H6 detections.
9. Examine Wiring And Connectors: Look for loose, corroded, or burned connectors at the ignitor, flame sensor, gas valve, and control board. Tighten or replace connectors as needed.
10. Check Pressure Switch And Venting: Ensure vent pipes are clear and the pressure switch tubing is unobstructed. Replace a failing pressure switch after confirmation.

How To Clean And Test The Flame Sensor

Cleaning the flame sensor is a common homeowner fix. Turn off power and gas, remove the access panel, locate the sensor (thin metal rod near burners), and loosen its mounting screw. Wipe the rod gently with fine-grit emery cloth or steel wool, avoiding deep scratches.

After cleaning, resecure the sensor, restore power, and cycle the furnace. If the burners light and H6 clears, the sensor was likely the issue. If the code persists, further testing or replacement may be necessary.

When To Replace The Ignitor Or Flame Sensor

Replace the ignitor if it shows visible cracks, has high resistance beyond manufacturer specs, fails continuity tests, or does not glow consistently. Ignitors are fragile and must be handled carefully during replacement.

Replace the flame sensor if cleaning does not restore reliable flame detection or if the sensor shows significant corrosion or physical damage. Use OEM or recommended replacement parts for compatibility.

Control Board, Gas Valve, And Complex Repairs

If basic fixes do not resolve H6, the fault may lie in the control board, gas valve, or complex electrical components. Control board failures can present intermittent faults, misreads, or failure to command the gas valve or ignitor.

Testing gas valve operation often requires a qualified technician with pressure testing tools and a multimeter. Replacement of control boards or valves should follow manufacturer instructions and local codes; many warranties require certified service for certain repairs.

Preventive Maintenance To Avoid H6 Errors

• Annual Professional Service: Schedule annual furnace inspection and tune-up with a licensed HVAC technician to test ignition components, gas pressures, and safety controls.
• Regular Filter Changes: Replace filters every 1–3 months depending on home conditions to maintain airflow and system health.
• Clean Burner Assembly: During professional service, ensure burners and combustion areas are cleaned to maintain consistent ignition.
• Check Vents And Chimney: Keep vents, flues, and chimneys clear of obstructions, nests, or debris.
• Monitor System Alerts: Note error codes promptly and act early to avoid lockouts and more extensive repairs.

When To Call A Professional

Contact a licensed HVAC technician if H6 persists after basic checks, if gas odor is present, or if the homeowner is uncomfortable performing internal checks. Professionals have the tools to test gas pressure, control boards, and combustion safety systems.

Persistent H6 can indicate failing components that require certified replacement to meet safety codes and maintain warranty coverage. Documenting the sequence and any prior repairs can speed diagnosis.

Common Model Variations And LED Diagnostics

Goodman models use several control boards with differing LED codes. The H6 label is widely used but exact flash patterns and additional diagnostic LEDs vary. Always consult the unit’s model-specific service manual or data plate for correct LED interpretation.

Many boards flash a repeating LED pattern and may provide a secondary code table on the blower compartment door. Photographing the LED sequence before resetting helps technicians identify intermittent faults.

Cost Considerations For Repairs

Costs vary by repair: flame sensor cleaning is low cost (parts plus basic labor), ignitor replacement is moderate, while control board or gas valve replacement can be substantial. Labor rates differ regionally across the U.S.

Obtaining multiple quotes and verifying technician credentials, insurance, and warranty terms helps ensure fair pricing and quality work. Many HVAC companies offer service plans that can reduce long-term repair costs through preventative maintenance.

Frequently Asked Questions (FAQ)

Can A Dirty Flame Sensor Cause H6?

Yes. A dirty flame sensor is one of the most common causes. Cleaning often restores proper flame detection and clears H6.

Is It Safe To Reset The Furnace After H6?

Resetting to clear the H6 once for testing is acceptable, but repeated resets without addressing the cause can be unsafe. If the code returns, proceed with diagnostics or call a technician.

How Long Should An Ignitor Last?

Ignitor lifespan varies but typically lasts several years. Frequent cycling or rough handling reduces lifespan. Replace when performance declines or physical damage is observed.

Will A Furnace Still Heat With H6 Active?

No. H6 indicates a safety lockout that prevents the burners from operating until the underlying problem is corrected and the furnace is reset.

Resources And Manufacturer Guidance

For model-specific procedures, consult the Goodman installation and service manual for the exact furnace model number. Manufacturer technical bulletins and authorized service centers provide official diagnostics and replacement part specifications.

State and local codes govern gas appliance repairs and may require licensed technicians for certain work. Homeowners should confirm local requirements before performing repairs beyond basic cleaning or visual inspections.