York Furnace 11 Red Flashes (YP9C Modulating)
Hard lockoutShown as: Eleven red flashes, two-second pause, repeating
Main blower failure. The main limit opened and did not reclose within five minutes, which the control reads as a failed blower motor or blower wheel.
Manual wording: “Eleven Red Flashes - Main blower failure - This flash code occurs when the main limit opens and fails to reclose within five minutes, indicating that the blower motor or blower wheel has failed.”
Documented for: YP9C, YPLC modulating furnaces
Likely causes, most common first
- Failed blower motor
- Failed blower wheel
What you can safely check yourself
- Check and replace the air filter
- Open blocked supply registers and clear the return grille
When to call a technician
Blower motor or wheel replacement is a technician job. Stop resetting the furnace if the code returns.
A York furnace throwing this code repeatedly has a reason — clearing the code without fixing the cause just hides it.
Source
- Installation Manual - Modulating ECM Residential Gas Furnace with ECM Motor, Models YP9C*C / TP9C*C / CP9C*C / LP9C*C (Up to 98% Modulating Multi-position), 1083292-UIM-A-0114 (Johnson Controls Unitary Products (York), YP9C*C (York Affinity modulating), and the identical TP9C / CP9C / LP9C chassis) · checked 2026-08-25