HVAC Code Lookup

York Furnace 8 Red Flashes

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

The flame was lost five times (four recycles) during one heating cycle. The furnace locks out for one hour and then restarts.

Manual wording: “8 RED FLASHES: This fault is indicated if the flame is lost five times (four recycles) during the heating cycle. Check for low gas pressure, dirty or faulty flame sensor or faulty gas valve.”

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

Likely causes, most common first

  1. Low gas pressure
  2. Dirty or faulty flame sensor
  3. Faulty gas valve

What you can safely check yourself

  • Check that other gas appliances in the house still work
  • Replace a dirty air filter
  • Check the outside vent and intake pipes for blockage

When to call a technician

Flame sensor cleaning and gas pressure checks are done with the burners running and require a manometer. Call a technician.

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

Sources

Other York codes