Rheem R801SA furnace code 0: Standby
Info — not a fault
What does 0 mean on a Rheem R801SA (801S downflow) furnace display? 0 is the normal standby display. The control is powered and waiting for a call from the thermostat; it does not indicate a fault.
Safe checks before calling
If the house is cold while 0 shows, confirm the thermostat is on HEAT with the setpoint above room temperature.
Questions about this code
What does 0 mean on a Rheem R801SA (801S downflow) furnace display?
0 is the normal standby display. The control is powered and waiting for a call from the thermostat; it does not indicate a fault.
Does Rheem R801SA furnace code 0 mean I need a repair?
No repair is needed for 0 by itself. If the thermostat is calling for heat and the display stays at 0, record the settings and book service, since the call may not be reaching the furnace.
How much does it cost to fix Rheem R801SA furnace code 0?
A normal standby display carries no repair cost on its own. A visit is only worth booking if the furnace fails to respond to a confirmed heat call.
Applies to
R801SA / 801S downflow single-stage 80% furnace with PSC motor
Different Rheem generations use different code maps. If your series isn't listed, don't assume this meaning — check your blower-door label.
Verified against Rheem 801S Series Installation Instructions — OEM143-14 mirror, p.34
Last verified 2026-10-07 · page updated 2026-10-07 · how we verify
Related Rheem furnace codes
These codes use the same rheem 801s downflow single-stage control (manual 92-24161-143-14) system.