HVAC Code Lookup

American Standard Furnace Continuous OFF

WarningShown as: LED completely dark

The control board is not receiving power. The manual's instruction for a dark LED is to check power to the furnace.

Manual wording: “Continuous OFF --- Check Power”

Documented for: *UD1 / *DD1 and CUB1 / CDB1 fan-assisted gas furnaces with the LED-only integrated furnace control

Likely causes, most common first

  1. No line power reaching the furnace
  2. Open circuit breaker or blown fuse
  3. Furnace disconnect switch off
  4. Blower door not fully seated, which opens the door switch and cuts power to the blower and gas valve

What you can safely check yourself

  • Check the breaker in your electrical panel and reset it if it is tripped
  • Check that the furnace switch is turned on - it is usually near the furnace, by the basement stairs, or in the ceiling
  • Make sure the furnace door is on properly and fully latched, especially after a filter change

When to call a technician

If the breaker and switch are on and the door is closed but the board is still dark, a technician needs to check the transformer, fuse, and wiring.

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

Sources

Other American Standard codes