To adjust your fireplace blower fan speed, locate the adjustment screw on the speed regulator of the blower. The fan remains at a very high speed when turned on. To adjust it to a lower speed, turn the regulator’s screw in a clockwise direction. It will slow down when the screw is at the point which is the maximum it could turn to, in the clockwise direction. In the same way, you could turn the screw in the opposite direction to increase the fan speed to a level you want.