An air handling unit (AHU) for a heating, ventilation, air conditioning, and refrigeration (HVACR) system includes a housing and a combustion heater disposed within the housing. The housing includes a combustion section with a first channel and a second channel. The combustion heater includes heat exchanger tubes and a tube support that supports heat exchanger tubes within the combustion section. The tube support slidably disposed in the first channel and the second channel. The combustion heater configured to be slidably removable from the AHU. An AHU for an HVACR system includes a housing with a fan section and a fan assembly disposed within the housing. The fan assembly including a pair of grooves slidably disposed on a pair of rails of the housing. The fan assembly configured to be both slidably removable from the AHU and liftably removable from the AHU.

A condensate drain system for a heating, ventilation, and/or air conditioning (HVAC) system includes a heat exchanger having a plurality of tubes configured to receive ambient air and fluidly coupled to a drain via a conduit, a valve positioned along the conduit between the plurality of tubes and the drain, where the valve is configured to enable a flow of condensate from within the plurality of tubes toward the drain in an open position and the block the flow in a closed position, and a controller configured to adjust a position of the valve based on feedback indicative of an operational state of the HVAC system.

A furnace for a heating, ventilation, and/or air conditioning (HVAC) system includes a first set of heat exchanger tubes positioned within an air flow path of the furnace through which an air flow may be directed, a second set of heat exchanger tubes positioned within the air flow path of the furnace, and a deflector baffle positioned within the air flow path and configured to direct a portion of the air flow toward the second set of heat exchanger tubes. The first set of heat exchanger tubes, the deflector baffle, and the second set of heat exchanger tubes are each respectively offset from one another in a direction of the air flow along the air flow path.

A burner assembly according to aspects of the disclosure includes a burner surface carried by a burner, the burner surface extending outward from a front side of the burner, a housing coupled to the burner on a side opposite the front side of the burner, a gasket disposed between the burner and the housing, a thermally anisotropic protective covering located on the front side of the burner and surrounding a perimeter of the burner surface, and an igniter positioned adjacent to the burner surface.

A flue collector box for a furnace having a cooling coil, a heat exchanger, and an inducer blower includes a housing having an interior chamber in fluid communication with the heat exchanger such that condensation generated in the heat exchanger flows to the interior chamber of the housing. A valve is connected to the housing and includes a pair of lips defining a fluid passage through the valve in fluid communication with the interior chamber. The lips have an open condition allowing condensation to exit the valve when the inducer blower is deactivated. The lips have a closed condition forcefully engaging one another when the inducer blower is activated to prevent condensation from exiting the valve.

A fuel cell system is disclosed. The fuel cell system includes: a fuel cell module including a plurality of unit cells for generating electrical energy by using oxygen of air and hydrogen of a reformed fuel gas; a first module including a burner part which burns an unreacted fuel gas and air discharged from the fuel cell module, an air-heating part which heats air through heat exchange with a hot combustion gas and a flame generated by the burner part and supplies the heated air to the fuel cell module, and a water vapor generation part which converts water, flowing through an inner portion thereof, into water vapor through heat exchange with a hot combustion gas generated by the burner part; and a second module which mixes a fuel supplied from an external fuel supply source and water vapor supplied from a water-vapor generator part.

A high turndown furnace for an air handling system. In one example, the furnace includes a plurality of tubes divisible by four with a first modulating valve supplying gas to ¼ of the tubes and a second modulating valve supplying gas to ¾ of the tubes. In one aspect, the furnace is capable of providing a 16:1 turndown. In one aspect, the furnace is capable of providing seamless turndown operation throughout the entire firing range.

A furnace with at least one adjustable baffle assembly, a heating, ventilation, and/or air conditioning (HVAC) system incorporating the same, and a method of operating the HVAC system are provided. The at least one adjustable baffle assembly is disposed adjacent to the furnace heat exchanger in the furnace. The at least one adjustable baffle assembly is configured to actuate, between a cooling position and a heating position. The at least one adjustable baffle assembly may be in a heating position when the HVAC system is in a heating mode. The at least one adjustable baffle assembly may be in a cooling position when the HVAC system is in a cooling mode. The actuation of the adjustable baffle assembly may increase the efficiency of the furnace and/or HVAC system.

A portable indirect fuel fired heater includes a burner assembly having a fuel burner to deliver fuel from a fuel supply to a combustion chamber of the heater and a combustion air blower to deliver combustion air to the combustion chamber with the fuel for combustion in the combustion chamber to produce exhaust gases. A heat exchanger receives air to be heated in heat exchanging relationship with at least a portion of the combustion chamber. A sensor senses an oxygen level as a partial pressure of oxygen in the exhaust gases. A controller operates an actuator operatively connected to the burner assembly to controllably vary the delivery rate of combustion air and thus vary the ratio of the air and fuel responsive to the oxygen level sensed by the combustion sensor so as to maintain the sensed oxygen level at a prescribed set point level stored on the controller.

A furnace for a heating, ventilation, and/or air conditioning (HVAC) system includes a heat exchanger tube including a tube inlet and a tube outlet, such that the heat exchanger tube is configured to receive combustion products via the tube inlet, circulate the combustion products through the heat exchanger tube, and discharge the combustion products via the tube outlet. Additionally, the furnace includes a collector box coupled to the heat exchanger tube and having a cavity configured to receive the combustion products via the tube outlet. The furnace includes a diverter plate disposed within the cavity, where the diverter plate overlaps the tube outlet to disperse the combustion products received via the tube outlet throughout the collector box.