Patent ID: 6634422
Filing Date: 2003-10-21
Classification: F24F

Abstract:
A method of controlling an economizer, comprising the steps of:operating a heating, ventilating, and air conditioning unit in one of a heating mode and a cooling mode to provide conditioned air to a plurality of zones, said unit having an economizer operable to allow variable amounts of outdoor air into said unit; sensing a first temperature representative of air returned to said unit from the plurality of zones; sensing a second temperature representative of the outdoor air; modulating the economizer to increase the amount of outdoor air entering said unit when the first temperature falls below a cooling setpoint, the second temperature is greater than the first temperature, and said unit is operating in the cooling mode; and modulating the economizer to increase the amount of outdoor air entering said unit when the first temperature rises above a heating setpoint, the second temperature is lower than the first temperature, and said unit is operating in the heating mode.