Your boiler is currently cooling down its internal components after finishing a heating cycle, which is a normal part of the shutdown process.

Heatingmode:Fanoverrun

What causes this fault?

This fault occurs when the boiler's control system detects that the fan is still spinning even after it was told to stop. The most common reason is a communication error between the main circuit board and the fan, or a physical fault within the fan motor itself that prevents it from shutting down correctly. Because the fan is a safety-critical component, the boiler pauses operation to prevent an unsafe mixture of gas and air.