Technical description
Fan over run
What causes this fault?
This status occurs when the boiler's fan continues to spin after the demand for heating or hot water has ended to clear any remaining combustion gases from the system. While it is usually part of the boiler's normal cooling-down process, it can indicate a minor delay in the communication between the control board and the fan. In rare cases, it may signal that the fan is beginning to wear out or that there is a slight fault with the electrical signals from the main circuit board.
DIY fix possible
Check if any radiators have been recently turned offEnsure the bypass valve (if visible) is openWait for the fan to finish its cooling cycleContact an engineer if the fan runs indefinitely without stopping