American Standard · Furnace / HVAC
9 flashes Inducer limit switch open
What this code means
The switch that confirms the inducer motor is running and pulling combustion air/exhaust properly is open, so the control won't allow the burners to light.
Most likely causes
- Blocked or restricted vent/flue termination
- Failing inducer motor
- Disconnected or pinched pressure/limit switch tubing
What to try first
Check the outside vent termination for blockage (leaves, snow, nests). Don't repeatedly reset — a stuck-open limit switch is doing its job.
Safety note: if this code returns after one clean reset, stop resetting it — repeated lockouts usually mean a real fault that needs a licensed technician. Never bypass a safety switch.
FAQ
What does American Standard error code 9 flashes mean?
Inducer limit switch open. The switch that confirms the inducer motor is running and pulling combustion air/exhaust properly is open, so the control won't allow the burners to light.
Can I fix American Standard code 9 flashes myself?
Usually not. Check the outside vent termination for blockage (leaves, snow, nests). Don't repeatedly reset — a stuck-open limit switch is doing its job. If the code returns after one reset, it needs a licensed technician.
What causes American Standard code 9 flashes?
The most common causes are: blocked or restricted vent/flue termination; failing inducer motor; disconnected or pinched pressure/limit switch tubing.
Other American Standard furnace codes
All American Standard furnace error codes →
Other furnace brands: Trane · Carrier · Lennox · Goodman · Amana · Rheem · Bryant · Generic · Nest
This information may contain errors or not apply to your exact model — always double-check it against your appliance's own manual before acting. If there's any chance of a gas, fire, electrical, carbon monoxide, or other safety hazard, stop and call a licensed professional or the appropriate agency (e.g. your gas utility) instead of relying on this page alone.