so this is not the answer I was looking for ...
is it possible that it is not well powered by the PSU ? would it still be shown in the statistics tab if it wasn't powered ?
Try connecting only that board to the controller. Make sure you have power to the board that supplies the fan too! You are using the 1300 watt EVGA?
I have power to all 4 boards, the fan is working.
Only one board is connected to the controller.
I use 2x 1000W PSUs
Perhaps it was not clear that we are now trouble-shooting. I was asking that you only power the board which is not hashing and only connect that board to the power supply. That would be board 8/24 (switch setting 00011) Disconnect the data cable interconnections to the other board and connect only the one long data cable from board 8/24 to the controller. MAKE SURE to keep power on the board that powers the fan but only power - no data connection.
Does that board work alone?