Updated 2026-06-25
Goodman Furnace 1 flash: What It Means & How to Fix It
Compiled & reviewed by Nikolai Tsyrenov · Updated 2026-06-25 · confidence: high
What does Goodman furnace 1 flash mean?
Lockout due to too many ignition retries (3) — failure to establish or maintain flame. Most often caused by Interrupted or low gas supply (e.g. partially closed manual gas valve, utility issue).
What Goodman furnace 1 flash means
Lockout due to too many ignition retries (3) — failure to establish or maintain flame.
Common causes
- Interrupted or low gas supply (e.g. partially closed manual gas valve, utility issue)
- Dirty, oxidized, or misaligned flame sensor
- Weak or failed hot-surface igniter
- Blocked flue/vent affecting flame stability
Homeowner-safe steps to try
- Confirm other gas appliances in the home work, which helps reveal a whole-home gas supply problem
- Check and replace a dirty air filter and ensure vents/returns are open
- Cycle the thermostat or power once to let the furnace attempt ignition again
- Do NOT open the burner compartment, clean the flame sensor, or adjust the gas valve — leave combustion work to a pro
When to call a licensed HVAC technician
If the basic checks below don't clear the code, the fault recurs, or anything involves the gas valve, burners, flame sensor or wiring, stop and book a licensed HVAC technician. Repairs to the combustion or gas system are not DIY.
⚠️ Safety first. Gas furnaces burn fuel and produce combustion gases. If you ever smell gas (a rotten-egg or sulfur odor), hear hissing, or your carbon-monoxide alarm sounds, do not touch light switches, thermostats, or the furnace — leave the home immediately and call your gas utility's emergency line or 911 from outside. Homeowners should limit themselves to simple, safe steps: setting the thermostat, checking and replacing the air filter, confirming the furnace switch and breaker are on, keeping supply registers and return grilles open, and clearing snow, ice, or debris from outdoor vent and intake terminations. Never bypass, jumper, or reset safety switches (limit, flame-rollout, or pressure switches), never open the gas valve or burner compartment, and never attempt combustion, electrical, or control-board repairs yourself. Error codes point toward a problem but are not a substitute for proper diagnosis — when in doubt, turn the system off and call a licensed HVAC technician. Keep working carbon-monoxide detectors on every level of your home.
When to call a pro: Call a licensed HVAC technician if the furnace locks out and won't relight — flame-sensor, igniter, and gas-valve service is required. If you smell gas, do not operate the furnace.
Goodman furnace 1 flash FAQ
What does Goodman furnace 1 flash mean?
Lockout due to too many ignition retries (3) — failure to establish or maintain flame.
What causes Goodman furnace 1 flash?
Common causes: Interrupted or low gas supply (e.g. partially closed manual gas valve, utility issue); Dirty, oxidized, or misaligned flame sensor; Weak or failed hot-surface igniter; Blocked flue/vent affecting flame stability.
Can I fix Goodman furnace 1 flash myself?
You can safely try: Confirm other gas appliances in the home work, which helps reveal a whole-home gas supply problem; Check and replace a dirty air filter and ensure vents/returns are open; Cycle the thermostat or power once to let the furnace attempt ignition again; Do NOT open the burner compartment, clean the flame sensor, or adjust the gas valve — leave combustion work to a pro. Call a licensed HVAC technician if the furnace locks out and won't relight — flame-sensor, igniter, and gas-valve service is required. If you smell gas, do not operate the furnace.
Other Goodman furnace codes
Goodman 2 flashesPressure-switch circuit is stuck closed at theGoodman 3 flashesPressure-switch circuit is open (did not closeGoodman 4 flashesPrimary limit circuit (high-limit switch) is oGoodman 5 flashesFlame sensed with no call for heat — the contrGoodman 6 flashesFlame-rollout switch is open — a safety shutdoGoodman 7 flashesLow flame signal — the flame-sense micro-amp sGoodman 8 flashesProblem with the igniter circuit.
Sources: hvacdirect.com · appliantology.org. General information for homeowners, not professional advice — confirm against your furnace's manual and a licensed technician.