E105
Device communication problem — no other devices on RSBus
This code typically points to
- Electrical noise on RSBus
- Miswired RSBus
- Loose i+/i- bus connections
Next checks to confirm
- Separate high-voltage wiring from RSBus
- Check miswired/loose stat-indoor-outdoor wiring
- Check for nearby high-voltage noise source
Escalation
Communication fault; clears after bus communications are restored
Reset behavior
Auto clears after communications recover.
Urgent
Fix now