American Standard · Furnace / HVAC
6 flashes Incorrect line voltage polarity
What this code means
Hot and neutral wiring at the incoming power connection are reversed, or there's a grounding fault.
Most likely causes
- Wiring fault during installation or electrical work
- Failing transformer
What to try first
This is an electrical fault needing a licensed technician to correct the wiring.
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 6 flashes mean?
Incorrect line voltage polarity. Hot and neutral wiring at the incoming power connection are reversed, or there's a grounding fault.
Can I fix American Standard code 6 flashes myself?
Usually not. This is an electrical fault needing a licensed technician to correct the wiring. If the code returns after one reset, it needs a licensed technician.
What causes American Standard code 6 flashes?
The most common causes are: wiring fault during installation or electrical work; failing transformer.
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.