Patent ID: 6958010

Claim:
An electrically powered ventilation system for a building crawl space to reduce the moisture content of enclosed air within walls of the crawl space, said system comprising: a fan unit having a fan operated by an electrical motor, said fan unit centrally located and orientated within the crawl space; said fan unit includes at least one inlet grill and an outlet grill for moving air within the crawl space through said fan unit to establish relatively high and low air pressure areas within the crawl space relative to the outside ambient air pressure; inlet vents in the walls adjacent to low air pressure areas allow for movement of relatively low moisture content outside ambient air into the crawl space; outlet vents in the walls adjacent to high air pressure areas allow for movement of relatively higher moisture content crawl space air to be discharged from the crawl space; a timer unit manually set to transmit a first electrical signal to activate said fan unit for ventilation periodic time periods that are set to optimally reduce the moisture content of the crawl space air; a controller unit having a control switch is connected between said timer unit and said fan unit to turn the fan unit on and off; and a main switch of said controller unit for directly transmitting electrical power to said control switch to turn on said fan unit in one position, and to activate control logic circuits for air temperature and humidity controls before selectively transmitting electrical power to said control switch to turn on said fan unit in the other position.