American Standard Furnace Code E05
Safety fault
The control is sensing a flame when there should not be one - for example with the gas valve commanded off.
Manual wording: “Flame detected, should not be present”
Documented for: A951X condensing and A801X induced draft furnaces with the seven-segment IFC display
Likely causes, most common first
- Flame detected, should not be present
- Gas valve leaking through or slow to close
- Flame sensing circuit fault
What you can safely check yourself
- Turn the furnace switch off and leave it off
- If you smell gas, leave the house and call the gas utility from outside
When to call a technician
Call a technician. A flame signal with the valve off points at the gas valve and is a safety issue.
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