The manufacturers specify a 3 degree drop of the ducting to outside to allow water to run outwards and not back into the room, and also to give a good seal to the flexible outer seal on to the outside brickwork. Any angle greater than 3 degrees may cause a poor external seal. Fans will run in almost any orientation, vertical or horizontal or anything in between in my experience. See original post please.
The manufacturers specify a 3 degree drop of the ducting to outside to allow water to run outwards and not back into the room, and also to give a good seal to the flexible outer seal on to the outside brickwork. Any angle greater than 3 degrees may cause a poor external seal. Fans will run in almost any orientation, vertical or horizontal or anything in between in my experience. See original post please.
