Goodman GMVC one flash: external ignition lockout

What Does Error 1 flash Mean?

On the documented Goodman GMVC80 control, one flash indicates external lockout after the furnace exceeds its ignition attempts. The control can automatically reset after one hour, while a thermostat or power interruption longer than five seconds can also reset it; none of those actions diagnoses why flame was not proved. Applies to: GMVC80 condensing gas furnaces This one-flash definition applies to the GMVC80 family in the cited Goodman installation instructions. Other Goodman boards use different LEDs and decimal codes, so identify the furnace and control before counting. Owner-safe checks: Keep furnace panels installed, record one full startup sequence and the repeating flash, and stop without creating additional ignition attempts. Qualified technician: Draft, vent, condensate, igniter, gas, burner, flame-current, grounding, safety, and control tests require licensed gas-furnace service.