Vents TT Silent-M EC U Series User Manual page 11

Remove the fan cover.
Connect the X1 and X2 terminal block counterparts.
Reassemble the fan in the reverse order.
Sequence of power supply connection
R1
SW
S1
11
Installation locations of the R1 potentiometer, X1 and X2
terminals are shown on the control board. DIP switch SW.
1
2
Supply power to the fan.