Abstract: A control system for a heating, ventilating, and air conditioning unit having a heating stage, a cooling stage, and an economizer is provided. The system includes a memory configured to store a first predetermined temperature range and a second predetermined temperature range. The system also includes a control having an input device configured to receive an indoor air temperature representative of the air in one or more zones and a supply air temperature representative of the air entering the one or more zones. The control selectively activates at least one of the heating stage, the cooling stage, and the economizer when the indoor air temperature is outside of the first predetermined temperature range. The control also selectively activates at least one of the heating stage, the cooling stage, and the economizer when the indoor air temperature is within the first predetermined temperature range and the sensed temperature of the supply air is outside of the second predetermined temperature range.

Abstract: A method for controlling a heating, ventilating, and air conditioning unit is provided. A conditioning unit having a heating stage, a cooling stage, a fan, and an economizer is operated to provide supply air to one or more zones. The temperature of air in the one or more zones and the temperature of air supplied to the one or more zones from the conditioning unit is sensed. At least one of the heating stage, the cooling stage, and the economizer is activated when the sensed temperature in at least one of the one or more zones is outside of a first predetermined temperature range. At least one of the heating stage, the cooling stage, and the economizer is activated when the sensed temperature of the air in the at least one of the one or more zones is within the first predetermined temperature range and the sensed temperature of the supply air is outside of a second predetermined temperature range.

Abstract: A system and method for controlling the stage of a compressor motor and/or fan motor of a heating, ventilation, and air-conditioning system. Preferably, said system and method are used with a reversible, two stage compressor motor. The method includes, for example, switching at least one contactor connected to a source of line power to remove the source of line power to a set of relays and to a compressor motor containing a run winding, a start winding, and a common lead; waiting a predetermined period of time; and controlling the set of relays by switching the set of relays to provide the source of line power to permit switching the source of line power to either the run winding or the start winding, wherein prior to the step of controlling, the at least one contactor removes the source of line power from the set of relays.

Abstract: A method and system for controlling a heating, ventilating, and air conditioning unit is provided. The system includes a conditioning unit having a heating stage, a cooling stage, and a fan. The conditioning unit operates in an active mode where one of the heating stage and cooling stage is activate to condition air in an enclosure. The conditioning unit also operates in a ventilation mode to provide supply air to the enclosure. A supply temperature sensor is provided to sense the temperature of the supply air. A central control operates to activate one of the heating stage and cooling stage when the conditioning unit is operating in the ventilation mode and the temperature of the supply air is outside of a predetermined range.

Abstract: A method and system for controlling a heating, ventilating, and air conditioning unit is provided. The system includes a conditioning unit having a heating stage, a cooling stage, and a fan. The conditioning unit operates in an active mode where one of the heating stage and cooling stage is activate to condition air in an enclosure. The conditioning unit also operates in a ventilation mode to provide supply air to the enclosure. A supply temperature sensor is provided to sense the temperature of the supply air. A central control operates to activate one of the heating stage and cooling stage when the conditioning unit is operating in the ventilation mode and the temperature of the supply air is outside of a predetermined range.

Abstract: A method and system for controlling a heating, ventilating, and air conditioning unit is provided. The system includes a conditioning unit having a heating stage, a cooling stage, and a fan. The conditioning unit operates in an active mode where one of the heating stage and the cooling stage is activated to condition air in an enclosure. The conditioning unit also operates in a ventilation mode to provide supply air to the enclosure. A supply temperature sensor is provided to sense the temperature of the supply air. A central control operates to activate one of the heating stage and the cooling stage when the conditioning unit is operating in the ventilation mode and the temperature of the supply air is outside of a predetermined range.

Abstract: The present invention is a system for controlling the quality of air in a building. The system includes a sensor disposed for sensing the air quality in a building. Upon a sensing of an air quality problem, the system issues a command to draw in additional outside air into the building to alleviate the problem. The issuing of such command can be made conditional on a measurement of outside air temperature. The flow of additional outside air may be limited or avoided altogether where drawing in additional outside air would adversely affect the inside air temperature. Additional air can be drawn into a building, for example, by opening an economizer, activating a fan system, or by increasing a pressure setpoint in a supply air duct.

Abstract: Method and apparatus are disclosed for responding to an unpermissible rise in the supply air temperature in any zone of a variable air volume system. A warning is generated to a controller in each zone which adjusts the air flow to the zone within predetermined limits. Different adjustment occur depending on whether the temperature of the space being heated is below the zone setpoint or above the zone setpoint.