Abstract: A compact secondary heat exchanger, installed in the path of room air through the casing of a gas furnace, utilizes a unitary condensing coil having parallel upper, middle and lower sets of tubes through which the flue gas passes sequentially to a collector manifold, exhausted by a blower. The coil is slanted downwardly from the hot gas manifold. Condensate formed in the first and second sets of tubes flows downward to an intermediate manifold between the first and second sets of tubing, condensate from this intermediate manifold is drained downward to a collector manifold beneath.

Abstract: An L-shaped, vertical partition within an air conditioner housing divides off a condenser compartment which has a supplementary air inlet and an air corridor therefrom. One panel of this partition mounts, at its side within the air corridor, the motor which drives the evaporator blower. An access door, opposite to the partition panel, permits the entire assembly to be removed for servicing and to permit access to the other parts. Where the blower system is to be used alternately with a resistance heater coil, this blower motor may be equipped with its own cooling fan.

Abstract: An electrical baseboard heater having multiple elongated electrical heating units aligned parallel to each other may be field wired at either of its ends. A preassembled heating assembly, when secured onto the base of the baseboard heater cabinet, forms a wiring raceway for return wiring from the nonadjacent terminals of the heating units and for secondary power supply wiring to the other end of the cabinet.

Abstract: Instead of constructing an air furnace cabinet as a separate unit and then installing the furnace components such as electrical heating elements, controls and a blower, in the present invention a blower scroll assembly and a heating element assembly are first constructed using flanged sheet metal panels as wide as the interior of the cabinet. The cabinet is then assembled about and integrally reinforced by these assemblies. Lines of securement of the flanges of these assemblies divide the exterior cabinet walls into smaller parts and afford to the cabinet strength and structural rigidity.

Abstract: For use in connecting flexible air-carrying ducts into rectangular sub-floor ducts, a knock-down collar, easily installed in the field, possesses sufficient rigidity to withstand the compression of a draw band by which a flexible duct is secured. Field assembly is by means of a drive cleat over 180.degree. flanges of the collar workpiece; tabs outstanding from the bends resist the hoop compression. A ring of inward-bent trapezoidal segments forms a flange presentable upwardly against the edge surface around an opening in a sub-floor duct with their tips bent upward and back to secure to such opening.