| | | For all its hood models, Val-cucine has adopted a special check valve that shuts when the motor is off, preventing unwanted air from flowing in from outdoors, and opens automatically when the motor is on. Unpleasant inconveniences may occur in absence of this valve. | | Due to particular circumstances that may occur in the home (draughts or drops in pressure) if the fumes outlet hole is near other flues it may take in the toxic gasses coming from the fireplace, stove or boiler of adjacent homes. Furthermore, if a check valve is not installed, cold air may | | come in from outdoors. Furthermore, due to the chimney effect, a hood without a check valve tends to extract the hot air from the room and convey it oudoors even when it is off, thus incresing heating costs. | | |