Opinion ID: 2828670
Heading Depth: 3
Heading Rank: 1

Heading: A fan recycling control apparatus for a central

Text: air conditioning (CAC) system comprising: a circulating fan; 4 ABT SYSTEMS, LLC v. EMERSON ELECTRIC CO. a central air conditioning system with ducts to distribute cooled and heated conditioned air throughout a building; a thermostat for activating and deactivating both the central air conditioning system and the circulating fan; said activating causing a continuous fan opera- tion, said deactivating causing no fan operation, said thermostat further having a selectable con- stant fan mode, and a recycle control for periodically activating and deactivating only the circulating fan after a preselected time period, since the central air conditioning system has been deactivated, or the circulating fan has been deactivated from the selectable con- stant fan mode. ’017 patent claim 1 (emphases added). Dependent claims 2–5 set forth limitations directed to specific types of HVAC system heating and cooling modes. They also set forth limitations relating to various types of heat sources for the system. The specification of the ’017 patent touts the benefits of running the fan periodically after a preselected time from heating or cooling deactivation based on fan “recycle control.” Those benefits include reduced air stagnation, dilution of point sources of indoor air pollution, and improved air cleaning. At the same time, periodic “recycle control” is said to reduce energy consumption in comparison to the “constant fan mode” operation of prior art thermostats.