Controlled mechanical ventilation system for house has pressure sensitive switch controlling speed of extractor fan motor

摘要

The ventilation system, consisting of a housing (2) with suction ports (3 - 7), an extractor fan and motor, and ducts (8) connecting the housing to the different rooms (12 - 14) of a house from which air is to be extracted and an exterior outlet, incorporates a pressure sensitive switch connected to a pressure detector inside the housing and controlling the extractor fan motor speed. The pressure detector has a probe located on the suction side of the fan and increases the motor speed when the suction effort drops below a set level, e.g. around 85 Pa, reducing the speed at about 120 Pa.