Furnace / HVAC
American Standard furnace error codes
Every American Standard furnace code in our database, with plain-English meanings, likely causes, and what to try before calling for service. Codes can vary by model and year — always confirm against the legend on your unit or its manual.
- 2 flashes System lockout — retries exceeded
- 4 flashes Limit switch open
- 5 flashes Flame sensed with gas valve off safety
- 6 flashes Incorrect line voltage polarity
- 7 flashes Gas valve circuit problem
- 8 flashes Low flame signal
- 9 flashes Inducer limit switch open
- 3 flashes Pressure switch error
- 12 Flame sensed with gas valve closed safety