HVAC Code Lookup

York Furnace 7 Red Flashes

Soft lockoutShown as: Seven red flashes, then a two-second pause, repeating

The burners failed to light on three trials for ignition, so the control locks out for one hour and then tries again.

Manual wording: “7 RED FLASHES: This fault code indicates that the flame could not be established during three trials for ignition... The furnace will lock out for one hour and then restart.”

Documented for: TG8S, TG9S, TM9E, TM9X, TM8X, TM9T, TM8T, TM9V, TM8Y, TM9Y

Likely causes, most common first

  1. Gas valve switch left in the OFF position
  2. Low or no gas pressure
  3. Faulty gas valve
  4. Dirty or faulty flame sensor
  5. Faulty hot surface ignitor
  6. Loose wires or a burner problem

What you can safely check yourself

  • Check that other gas appliances in the house (stove, water heater) still work - if none do, the gas supply is out
  • Replace a dirty air filter
  • Check the outside vent and intake pipes for blockage
  • Cycle the furnace off and on once at the service switch to let it retry

When to call a technician

Anything past confirming you have gas to the house - ignitor, flame sensor, gas valve - is technician work in a live gas compartment.

A York furnace throwing this code repeatedly has a reason — clearing the code without fixing the cause just hides it.

Sources

Other York codes