Fault Code Lookup

HVAC Sales Master
C
Compressor / cooling call active
This code typically points to
  • Normal cooling or heat-pump cooling demand

Next checks to confirm
  1. Verify thermostat demand and outdoor-unit operation if cooling expected

Escalation
During lockout, control may display the lockout error instead of C
Reset behavior
Automatic with call state.
Informational
No action needed
Source
Rheem Select / W801T Installation Instructions, lockout section stating control will display lockout error instead of 'C' or 'F'