An exhaust fan assembly is provided for expelling contaminated air from a building. The assembly includes a plenum, a fan assembly attached to the plenum, and a windband mounted on top of the fan assembly. The fan assembly is constructed of cylindrical outer and inner walls which define a bearing chamber and surrounding annular space. A fan driven by a shaft extending downward from the bearing chamber draws exhaust air from the plenum and blows it up through the annular space to a nozzle at the top of the fan assembly.

A furnace assembly comprising a non-condensing furnace with a draft inducer. The draft inducer includes a permanent magnet electrically commutated motor and a draft inducer blower fan. The motor includes a stator, a rotor, a motor cooling fan, and a controller. The rotor being rotatable relative to the stator, the fan being operatively coupled to the rotor such that rotation of the rotor causes rotation of the fan, the controller being configured to selectively operate the motor in first and second different torque ranges of the rotor, with the first and second torque range operating within a fixed percentage and within a fixed percentage of each other. The controller being configured such during normal operation, the motor is not operable at any torques between the first torque range and the second torque range except during transitionary periods.

Impeller for a motor-driven chimney draft system, comprising a flue gas impeller (10) for creating, in a flue gas passage, a draft in a flue gas downstream direction. A flue gas deflector disk (20) is situated downstream relative to the flue gas impeller (10) and connected to the flue gas impeller (10); and a hub for connecting the impeller to an end portion of a driving shaft of a motor (100), wherein the hub and the end portion of the driving shaft, when connected, are both situated downstream relative to the flue gas deflector disk (20), the hub indirectly connected to the flue gas deflector disk (20) by means of intermediate members. Advantageously the intermediate members are impeller blades (40) connected to the downstream side of the flue gas deflector disk (20) and to a venting disk (30) with venting holes (31, 32) so as to form a turbine.

A fan unit a nozzle assembly including a plurality of nozzles configured to receive an air flow and to expel the air flow through a plurality of outlets corresponding to the plurality of nozzles. A controller configured to control a longitudinal movement of a nozzle of the plurality of nozzles based on an operating condition associated with the fan unit.

A fuel-fired heating appliance has two fuel flow paths to a burner, each actuatable to a closed state and to an open state. A heat exchanger is in fluid communication with an area proximate the burner. A controller executes the steps: (a) while the first fuel flow path is closed, opening the second flow path; (b) following ignition of fuel flowing from the second flow path, opening the first fuel flow path; and (c) following step (b), closing the second fuel flow path while opening the first fuel flow path.

A high efficiency heating apparatus for heating fluids and cooking mediums, such as oil or shortening within a fryer, includes one or more natural draft combustion chambers that are affixed to exterior surfaces of a fry tank.