!!
critical Honeywell
Error Code Sylk Device Communication Failure
A high-severity alarm indicating the thermostat has lost communication with a connected Sylk device or sensor.
? What Causes This
Wiring disconnection, Sylk device failure, or communication bus error.
✓ How to Fix It
- Check Sylk bus wiring connections.
- Verify Sylk device is powered and functioning.
- Check for short circuits on the bus.
- Contact service personnel.
Source: page 118 of the official manual
From the manual
