Fault Code Lookup

HVAC Sales Master
Steady RED LED
Control fault detected or 115V present without 24V
This code typically points to
  • 24V control loss
  • Control internal fault

Next checks to confirm
  1. Verify both 24V and 115V to board
  2. If both present and fault remains, replace board

Escalation
Board-level fault if power is confirmed.
Reset behavior
Requires board replacement if confirmed.
Urgent
Fix now
Source
YP9C install manual