American Standard error codes
8 documented codes with ranked causes, repair costs, and step-by-step guidance.
American Standard furnace code chart (8)
American Standard Furnace — 8 flashes American Standard Furnace 8 Flashes: Low Flame Sense American Standard furnace 8 flashes means a weak flame-sense signal from a dirty sensor. Causes, safe checks and repair costs from $0 DIY to $250. American Standard Furnace — 2 flashes American Standard Furnace 2 Flashes: Causes & Fixes American Standard furnace 2 flashes means an ignition-retry lockout that auto-resets in 1 hour. See causes, safe checks, and repair costs from $0 to $1,200. American Standard Furnace — 3 flashes American Standard Furnace 3 Flashes: Causes & Fixes American Standard furnace 3 flashes means a pressure switch fault. Common causes, safe checks, technician diagnosis, and repair costs from $0 to about $1,200. American Standard Furnace — 4 flashes American Standard Furnace 4 Flashes: Open Limit Circuit 4 flashes means an open high-limit or rollout switch from restricted airflow or overheating. Causes, safe checks, fixes and $0–$3,500 costs. American Standard Furnace — 5 flashes American Standard Furnace 5 Flashes: Flame With Gas Off American Standard furnace 5 flashes means flame sensed with the gas valve off. Causes, safe checks, and repair costs from $0 to $700+. American Standard Furnace — 6 flashes American Standard Furnace 6 Flashes: Reversed Polarity Fix American Standard furnace 6 flashes means reversed 115 VAC polarity or poor grounding. Causes, safe checks, and repair costs from $0 DIY to $350. American Standard Furnace — 7 flashes American Standard Furnace 7 Flashes: Gas Valve Circuit American Standard furnace 7 flashes means a gas valve circuit error. Causes, safe checks, and repair costs from $0 DIY to $1,200+ pro. American Standard Furnace — 9 flashes American Standard Furnace 9 Flashes: Igniter Circuit Fix American Standard furnace 9 flashes means an open igniter circuit or low current draw. Causes, safe checks, and repair costs ($0 DIY–$350).