E348
No 24V output on Y2 of integrated control with non-communicating outdoor unit
This code typically points to
- Y2 relay / stage-2 pilot relay contacts did not close
- Relay coil did not energize
- No input back to IFC chip
Next checks to confirm
- Verify stage-2 call is present
- Check Y2 output from integrated control
- Replace integrated control if relay/output fault is confirmed
Escalation
Critical alert
Reset behavior
Cleared after reset and Y1 input is sensed.
Urgent
Fix now