York Furnace 3 Amber Flashes (YP9C Modulating)
StatusShown as: Three amber flashes, two-second pause, repeating
Normal operation - the burner is still on at the end of the heating cycle after the wall thermostat has been satisfied. Not a fault.
Manual wording: “Three Amber flashes - Normal operation, burner is on at end of heating cycle after wall thermostat has been satisfied.”
Documented for: YP9C, YPLC modulating furnaces
Likely causes, most common first
- Normal end-of-cycle burner operation on the modulating control
When to call a technician
No service needed.
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