American Standard S8X1 furnace code CP1: First-stage compressor
Info — not a fault
What does CP1 mean on an American Standard Silver S8X1 gas furnace display? CP1 means the thermostat is calling for first-stage cooling or heat-pump operation. It is a normal demand display, not a furnace fault.
Safe checks before calling
If you expected gas heat, check whether the thermostat is set for cooling or heat-pump operation.
Questions about this code
What does CP1 mean on an American Standard Silver S8X1 gas furnace display?
CP1 means the thermostat is calling for first-stage cooling or heat-pump operation. It is a normal demand display, not a furnace fault.
Does American Standard S8X1 furnace code CP1 mean I need a repair?
CP1 needs no repair. If comfort is poor while it shows, the outdoor cooling or heat-pump equipment and thermostat setup are what a technician should check.
How much does it cost to fix American Standard S8X1 furnace code CP1?
CP1 is a normal display and implies no repair bill. Any cost would come from separately diagnosing outdoor equipment that underperforms.
Applies to
S8X1A040M3PSCA · S8X1B040M2PSCA · S8X1B060M4PSCB · S8X1B080M4PSCB · S8X1C080M5PSCA · S8X1C100M5PSCB · S8X1D120M5PSCA
Different American Standard generations use different code maps. If your series isn't listed, don't assume this meaning — check your blower-door label.
Verified against Installation, Operation, and Maintenance — Upflow/Downflow/Horizontal Gas-Fired,1–Stage and2–Stage Induced Draft Furnaces with High Efficiency Motor, p.55
Last verified 2026-10-07 · page updated 2026-10-07 · how we verify
Related American Standard furnace codes
These codes use the same american standard silver s8x1 furnace control display (2024 iom) system.