V-TAC VT-4012-3 Manual Del Usuario página 7

5. Take the Fan Blade(3); slide it onto the Motor Spindle(10),
after first removing the plastic spindle cover. Ensure that the
notch on the rear of the fan blade fits over the splines on the
spindle (arrowed right).
NB Rear Guard removed for clarifty.
6. Secure the fan blade to the motor spindle by screwing on the
Blade Retaining Nut(11) in an anticlockwise direction.
NB the retaining nut is reverse threaded.
7. Remove the small Guard Nut & Screw from the Front Guard.
ENGLISH