Wire unit (reference C ) of the fan (F4) of the heat exchanger is disconnected.

Check the connection of the wire unit of the fan above the heatexchanger.

Wire unit of the fans and motor units (reference W ) disconnected from the Power Backplane.

Remove the Input & Communication unit and check if the wireunit is inserted in the Power Backplane.

Blocked fan.

Unblock the fan. Ensure that the fan can turn freely.

Damaged wire unit.

Check if the wire unit of the fan is not damaged. Repair ifpossible, otherwise replace with new one.

Fan end of life.

Replace the fan. See service manual chapter Heat exchanger fan.

Malfunction Fan Control Board

Replace the Fan Control Board.

Other fans are also not spinning.

Replace the SMPS Board.

Defect Power Backplane

Replace the Power Backplane.