Your boiler has detected an internal electronic communication error or a temporary sensor discrepancy and has paused operation for safety.

Temporary fault code (Refer to section 7.10)

What causes this fault?

This fault occurs when the boiler's central control board stops receiving consistent data from its internal sensors or temporary electrical interference disrupts the system. It is often caused by a failing thermistor sending incorrect temperature readings or a maturing circuit board that can no longer process signals reliably. The boiler pauses briefly to prevent overheating or damage until it can verify that all components are communicating correctly.