York 1 red flash: Flame was sensed when there was not a call for heat

Source: York manual (PDF) (opens in a new tab) ↗ · Updated

Status code1 red flashYork
What does York 1 red flash mean?

Flame was sensed when there was not a call for heat. The control turns on both the inducer motor and the supply air blower.

Call a pro: jump to when to call a pro Equipment type: furnace
How it shows: LED behind the blower-door view port on a York TG9S. Each flash is 1/3 second on and 1/3 second off, then a 2-second pause: 1 red flash

York TG9S 1 red flash means flame was sensed with no call for heat. The control runs the inducer and the supply blower. The only check in that paragraph is a leaking or slow-closing gas valve. It is not 7 red flashes, which is three failed ignition trials, and it is not 10 red flashes, which is the gas valve energized with no call for heat. If you smell gas, leave. Do not reset this to see if the smell goes away.

Likely causes

  • A leaking or slow-closing gas valve

Safe checks for 1 red flash

  1. If you smell gas, leave the building and call the gas supplier from outside. Do not reset the furnace to clear the smell
  2. Techniciancheck for a leaking or slow-closing gas valve
Safety firstIf you smell gas, do not touch any electrical switch or use a phone in the building; leave immediately and call your gas supplier from outside. Turn off electrical power at the furnace switch or breaker before opening any panel, and never bypass or jumper a limit, rollout or pressure switch. Gas valve, burner, venting, wiring and control-board work should be done by a licensed HVAC technician.

Capacitors can hold a charge after the power is off. Safety terms.

When to call a pro

Call a licensed HVAC technician. York's diagnostics say to check for a leaking or slow-closing gas valve, and the same section says never to bypass a safety control.

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Related York codes

11 red flashesThe main limit switch has opened10 red flashesThe gas valve is energized with2 red flashesThe pressure switch is closed when4 red flashesThe main limit switch has opened3 red flashesThe pressure switch contacts are open7 red flashesThe flame could not be established

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