American Standard Furnace Code E6.3
Hard lockout
Igniter fault. Either the igniter relay on the control has failed or the igniter itself is open (burned out).
Manual wording: “(1) Igniter relay fails (2) Igniter open”
Documented for: A951X condensing and A801X induced draft furnaces with the seven-segment IFC display
Likely causes, most common first
- Igniter relay fails
- Igniter open
What you can safely check yourself
- Turn the furnace switch off and back on once to see whether the furnace attempts to light
When to call a technician
Call a technician. A hot surface igniter is fragile and lives in the burner compartment; replacing it or the control board is not a homeowner job.
A American Standard furnace throwing this code repeatedly has a reason — clearing the code without fixing the cause just hides it.
Sources
- Installer's Guide - Upflow/Horizontal and Dedicated Downflow Gas-Fired, Direct/Non-Direct Vent, Single Stage Condensing Furnaces with High Efficiency Motor (88-A951X001-1D-EN) (American Standard Heating and Air Conditioning, A951X040BU3SAB through A951X120DD5SAB single-stage 95% condensing furnaces (Silver 95 family)) · checked 2026-08-25
- Installer's Guide - Upflow/Downflow/Horizontal Left/Right Gas-Fired, Single Stage Induced Draft Furnaces with High Efficiency Motor (88-A801X003-1C-EN) (American Standard Heating and Air Conditioning, A801X026AM2SC through A801X120DM5SC single-stage 80% induced draft furnaces (Silver 80 family)) · checked 2026-08-25