Patent ID: 9249980
Filing Date: 2016-02-02
CPC Classification: F24F

Claim Text:
1. A self-contained air unit for installation on a roof top of a building for circulating air through said building, said unit comprising a housing having a first blower therein, said first blower being connected into a circulation system to circulate air into and out of said building, the air circulation system having the first blower connected to an air supply to the building, an air return from the building and a fresh air supply from ambient air to supply fresh air into the air circulation system, said unit having a pressure relief opening that is independent of the air circulation system, said pressure relief opening being connected into a first passage and a second passage within said unit, said first passage being connected to ambient air, said second passage being connected through a damper to a second blower and to ambient air, said second blower being connected to remove air from said second passage and from said air circulation system to ambient air when said second blower is operating, said pressure relief opening and said first and second passages being constructed to allow air to pass through said passages from said pressure relief opening to ambient air whenever pressure of air within said building exceeds the pressure of ambient air and said second blower is not operating, wherein said damper is a relief bypass damper located between said first passage and said second passage, said air circulation system having an air return from said building, said air return having a first damper located between said air return and said second blower.