Your boiler has lost communication between its internal computer and parts like the thermostat due to an electrical connection issue.

eBUS error – possible short circuit

What causes this fault?

This fault occurs when the boiler's internal communication system, known as the eBUS, suffers an electrical failure or short circuit. It is often caused by moisture getting into the wiring, a loose connection to the thermostat, or even two wires touching where they shouldn't. This prevents the control board from receiving instructions, causing the system to shut down for safety.