Abstract: A representative mechanical draft system includes an in-line draft inducer that comprises a motor and a backward-inclined impeller. The mechanical draft system also includes an economizer coupled to the in-line draft inducer, where the economizer comprises a housing and a horizontally mounted heat recovery unit.

Abstract: Fan assemblies, mechanical draft systems and methods are provided. In this regard, a representative mechanical draft system for use with multiple appliances includes: a chimney operative to direct combustion products from multiple appliances; a chimney fan operative to draw combustion products from the chimney; and a controller operative to adjust an operating speed of the chimney fan such that, responsive to a change in pressure in the chimney, the controller adjusts the operating speed of the chimney fan to maintain a desired pressure in the chimney.

Abstract: A representative mechanical draft system for drawing exhaust gasses from a chimney includes: an exhaust fan assembly having: a housing defining a chamber and having opposing openings, the opposing openings having a centerline extending therebetween, a first of the openings being operative to intake a flow of gasses, a second of the openings being operative to exhaust the flow of gasses from the chamber; and a centrifugal fan having a motor and an impeller, the motor being mounted external to the housing, the impeller being positioned within the chamber, a rotational axis of the impeller being inclined with respect to the centerline extending between the openings of the housing.

Abstract: Fan assemblies, mechanical draft systems and methods are provided. In this regard, a representative mechanical draft system for use with multiple appliances includes: a chimney operative to direct combustion products from multiple appliances; a chimney fan operative to draw combustion products from the chimney; and a controller operative to adjust an operating speed of the chimney fan such that, responsive to a change in pressure in the chimney, the controller adjusts the operating speed of the chimney fan to maintain a desired pressure in the chimney.

Abstract: Systems and method for controlling the flow of air through a mechanical draft system are disclosed herein. A pressure controller for controlling air pressure comprises an appliance controller configured to control the operation of a plurality of appliances, an intake fan controller configured to control the speed of an intake fan, and an exhaust fan controller configured to control the speed of an exhaust fan. The pressure controller also includes a processor configured to receive a differential pressure signal and to control the operation of the appliances, the speed of the intake fan, and the speed of the exhaust fan in response to the differential pressure signal.

Abstract: Systems and method for controlling the flow of air through a mechanical draft system are disclosed herein. A pressure controller for controlling air pressure comprises an appliance controller configured to control the operation of a plurality of appliances, an intake fan controller configured to control the speed of an intake fan, and an exhaust fan controller configured to control the speed of an exhaust fan. The pressure controller also includes a processor configured to receive a differential pressure signal and to control the operation of the appliances, the speed of the intake fan, and the speed of the exhaust fan in response to the differential pressure signal.

Abstract: Systems and method for controlling the flow of air through a mechanical draft system are disclosed herein. A pressure controller for controlling air pressure comprises an appliance controller configured to control the operation of a plurality of appliances, an intake fan controller configured to control the speed of an intake fan, and an exhaust fan controller configured to control the speed of an exhaust fan. The pressure controller also includes a processor configured to receive a differential pressure signal and to control the operation of the appliances, the speed of the intake fan, and the speed of the exhaust fan in response to the differential pressure signal.