Goodman Furnace Ignites Then Shuts Off: Causes and Fixes

The Goodman furnace ignites then shuts off shortly after startup is a common troubleshooting search for homeowners seeking reliable heating. This article outlines the most likely causes, diagnostic steps, safety considerations, and practical fixes to restore steady operation. It focuses on clear, actionable guidance while highlighting when to call a professional.

Symptom	Likely Cause	Quick Fix
Burner Ignites Then Goes Out	Flame Sensor Or Dirty Burner	Clean Or Replace Flame Sensor; Clean Burner
Blower/Fan Stops With Flame Out	Limit Switch Or Overheat	Check Airflow, Clean Filter, Inspect Ducts
Repeated Attempts To Ignite	Ignitor Or Gas Valve Issue	Test/Replace Ignitor; Check Gas Supply
Short Cycling On Thermostat	Thermostat Or Wiring	Verify Settings, Replace Or Reposition Thermostat

How A Goodman Furnace Ignition Cycle Works

A basic understanding of the ignition cycle helps diagnose why a Goodman furnace ignites then shuts off. When the thermostat calls for heat, the furnace sequence typically involves the inducer motor, pressure switch, ignition system (hot surface ignitor or intermittent pilot), gas valve, flame sensor, and then the main burners stay lit while the blower operates.

If any component fails to confirm safe ignition or proper flame detection, the control board will interrupt the gas supply and shut the furnace down to prevent unsafe conditions. This safety-first logic explains why a furnace may ignite momentarily and then shut off.

Common Causes Goodman Furnace Ignites Then Shuts Off

Dirty Or Faulty Flame Sensor

The flame sensor verifies that burners have lit. A soiled sensor cannot detect flame and causes the furnace to shut off after ignition. Cleaning the sensor with fine emery cloth often resolves the issue, but repeated failures may indicate sensor aging or improper flame alignment.

Weak Or Cracked Ignitor

A failing hot surface ignitor may glow but not sustain a strong ignition, causing the control board to cycle off after an incomplete light. A weak ignitor should be replaced; testing it with a multimeter for continuity provides confirmation.

Gas Valve Or Gas Supply Problems

Intermittent gas pressure or a faulty gas valve can allow initial ignition but then fail, causing burners to shut off. Check that gas is on, other gas appliances work, and the gas valve is operating correctly. Gas issues require caution and often professional service.

Blocked Or Dirty Burners

Accumulated dust, rust, or insect debris on burners can cause inconsistent flame and flame rollout, leading to shutdowns. Cleaning burners and ensuring proper flame pattern improves stability and efficiency.

Overheating And Limit Switch Trips

Restricted airflow from dirty filters, closed vents, or blocked ducts can cause the heat exchanger to overheat, tripping the high-limit switch and shutting the burners off. Restoring airflow and verifying proper blower operation prevents repeated trips.

Pressure Switch Or Inducer Motor Failure

The inducer motor creates draft and the pressure switch confirms airflow. If the inducer motor fails or the pressure switch is out of calibration or clogged, the system may ignite but then shutdown when interlocks fail to verify safe conditions.

Thermostat Or Wiring Issues

A malfunctioning thermostat or shorted wiring can send false off signals shortly after ignition. Verify thermostat settings, batteries, and wiring connections before replacing major components.

Diagnostic Steps To Identify The Problem

Safety First

Before inspecting a furnace, turn off power and gas to the unit. Use manufacturer guidelines and if unsure, call a qualified HVAC technician. Natural gas and electricity pose hazards.

Observe The Error Codes

Goodman control boards often flash LED error codes that point to specific faults. Consult the furnace’s manual or the label on the unit to interpret codes. Document blinking patterns to aid diagnosis.

Check The Flame Sensor

Locate, remove, and visually inspect the flame sensor for carbon buildup. Lightly clean with fine emery cloth or alcohol and reinstall. If cleaning fixes the issue for only a short time, consider sensor replacement.

Inspect The Ignitor

Examine the hot surface ignitor for cracks or damage. Test continuity with a multimeter; a broken or high-resistance ignitor needs replacement. Avoid touching the ignitor surface with bare hands when handling.

Verify Gas Supply And Pressure

Confirm the gas shutoff valve is open and other gas appliances in the home are working. If the furnace intermittently receives gas, contact the utility. Technicians can measure manifold pressure to verify proper gas valve operation.

Examine Burners And Flame Pattern

With the furnace running, observe burner flames: they should be mostly blue with minimal yellow tips and stable. Sooty or floating flames suggest combustion issues, blocked ports, or gas/air mixture problems.

Test Limit Switch And Airflow

Inspect air filter, return vents, and supply registers. Replace a dirty filter and ensure vents are open. If the limit switch repeatedly trips, the heat exchanger may be overheating because of restricted airflow or a failing blower motor.

Check Inducer Motor And Pressure Switch Tubing

Listen for the inducer motor startup noise and ensure it runs smoothly. Examine the pressure switch tubing for blockages and the switch for proper closure. Replace cracked tubing or faulty switches as needed.

Evaluate Thermostat Function

Set the thermostat to call for heat and watch the control sequence. Swap in a known-good thermostat or replace batteries to rule out thermostat issues. Check wiring for loose or corroded connections.

Step-By-Step Fixes Homeowners Can Try

Clean Or Replace The Flame Sensor

Turn off power and gas, remove the sensor, clean with emery cloth or isopropyl alcohol, and reinstall. If the furnace still shuts off, replace the flame sensor with an OEM or compatible part.

Replace A Faulty Ignitor

If the ignitor is cracked or fails continuity, replace it. Follow manufacturer instructions for the correct part number and handle it carefully to avoid damage during installation.

Clean Burners And Combustion Area

Remove accumulated debris from burners, burner box, and surrounding areas. Use a brush and vacuum to clear dust and insects. Properly aligned, clean burners support consistent flames and flame sensing.

Restore Proper Airflow

Replace clogged air filters, open blocked return/supply vents, and inspect ductwork for obstructions. If the blower motor is weak, a professional can test amp draw and replace or repair the motor as needed.

Address Pressure Switch And Inducer Problems

Clear condensate or debris from inducer pathways and replace cracked pressure switch tubing. If the inducer motor is noisy or fails to reach speed, replacement or motor servicing is typically required.

Verify Gas Valve And Supply

For suspected gas valve problems, restrict work to licensed professionals. A technician will check manifold pressure, gas valve solenoids, and the gas regulator to identify and repair leaks or mechanical failures.

Update Thermostat Or Wiring

Replace an old thermostat or correct miswiring. Ensure thermostat placement avoids drafts or direct sunlight. Professional electricians or HVAC technicians can test control signals from the thermostat to the furnace board.

When To Call A Professional

Call a licensed HVAC technician if the furnace continues to ignite then shuts off after basic cleaning and checks, or when dealing with gas valves, manifold pressure, or complex controls. A pro should inspect the heat exchanger for cracks, test safety switches, and perform combustion analysis.

If error codes indicate safety interlocks like rollout switches or heat exchanger failures, immediate professional attention is required to protect occupants and the property.

Preventive Maintenance To Avoid Future Short Cycling

Regular maintenance reduces the chance a Goodman furnace ignites then shuts off. Schedule annual professional tune-ups, replace air filters every 1–3 months, keep the area around the furnace clean, and ensure carbon monoxide detectors and smoke alarms are functional.

• Replace Filters Regularly: Improves airflow and prevents limit trips.
• Annual Tune-Up: Technicians clean burners, test safety devices, and optimize combustion.
• Keep Vents Open: Avoid closing too many supply registers which can increase static pressure.
• Inspect For Pests: Insects and rodents can clog burners and pressure tubes.

Safety Considerations And Carbon Monoxide

Repeated ignition problems and abnormal burner behavior require caution because improper combustion can increase carbon monoxide (CO) risk. Install CO detectors near sleeping areas and test them monthly. If CO alarm activates or a furnace is suspected of leaking combustion products, evacuate and call emergency services and a qualified HVAC technician.

Parts, Costs, And Typical Repair Timelines

Common parts associated with a Goodman furnace that ignites then shuts off include flame sensors ($20–$80), hot surface ignitors ($40–$200), pressure switches ($30–$150), and inducer motors ($150–$500). Labor and diagnostic fees vary by region; expect a professional repair visit to take 1–3 hours depending on the issue complexity.

Cost estimates: minor fixes like cleaning or sensor replacement often run under $200, while inducer motor or gas valve repairs may exceed $500. Heat exchanger or major control board replacements can be significantly more expensive and may prompt evaluation of replacement versus repair.

How To Use Manufacturer Resources And Warranties

Goodman manuals, wiring diagrams, and diagnostic LED code charts are valuable. Check the furnace data plate for model and serial numbers when looking up parts or calling support. Many Goodman parts carry limited warranties; verify coverage before paying for parts or labor.

If the furnace is under warranty, contact the dealer or Goodman customer service to understand authorized service provider requirements to keep warranty valid.

Key Takeaways For Homeowners

• Most Common Cause: Dirty flame sensor or ignition components cause the Goodman furnace to ignite then shut off.
• Simple First Steps: Clean flame sensor, replace filter, observe error codes, and inspect ignitor.
• Call A Pro If: Gas valve, inducer motor, pressure switch, or heat exchanger issues are suspected.
• Safety Priority: Address combustion anomalies promptly and use CO detectors.

Following these diagnostic steps and fixes will resolve the majority of cases where a Goodman furnace ignites then shuts off. When in doubt, prioritize safety and consult a licensed HVAC technician to ensure reliable, efficient, and safe heating operation.