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York 7 red flashes: The flame could not be established during three trials for ignition

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

Status code7 red flashesYork
What does York 7 red flashes mean?

The flame could not be established during three trials for ignition. The furnace locks out for one hour and then restarts.

Homeowner part this code names: furnace flame sensor.

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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: 7 red flashes

York TG9S 7 red flashes means flame was not established in three ignition trials. The lockout lasts one hour, then the control tries again. The manual says to check that the gas valve switch is ON, then low or no gas pressure, a faulty gas valve, a dirty or faulty flame sensor, a faulty hot surface ignitor, loose wires, or a burner problem. The gas-valve switch and whether other gas appliances light are the homeowner checks. Eight red flashes is flame that was established and then lost five times.

Likely causes

  • Gas valve switch not in the ON position
  • Low or no gas pressure
  • Faulty gas valve
  • Dirty or faulty flame sensor
  • Faulty hot surface ignitor
  • Loose wires or a burner problem

Safe checks for 7 red flashes

  1. Check that the switch on the gas valve is in the ON position, and that other gas appliances in the home still light
  2. Techniciancheck gas pressure, the gas valve, the flame sensor, the hot surface ignitor, wiring and the burners
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 if the gas valve switch is ON and 7 red flashes return after the one-hour lockout.

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Parts & tools for this fix

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Furnace flame sensor: guide

In this code: Dirty or faulty flame sensor

Liberon grade 0000 ultrafine steel woolSearch: York furnace flame sensorSearch: Scotch-Brite pads, fine

Furnace hot surface igniter: guide

In this code: Parts list for this code: Hot surface igniter

See the guide for what to look for when buying one.

Nut driver set: guide

In this code: Panels and parts on a furnace are held by hex-head screws; a nut driver grips them without stripping.

See the guide for what to look for when buying one.

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