Abstract: A three-member molded plastic housing for rooftop air conditioners, including base and intermediate members having molded portions which together provide component lower and upper compartment walls and blower scrolls. The third member, an outer shroud, abuts sealedly along a roof ridge of the intermediate member to prevent recirculation within the shroud of condenser blower outlet air. The base member has downwardly molded projections for facilitating positioning the unit over a roof opening and resisting sideward forces.

Abstract: A two-piece plastic duct utilizing snap-together latch tongue and complementary engaging provisions together with overlapping sealing flanges to make adequately airtight duct assemblies. The duct walls consist of narrow trimming flats with measurement indicia; these flats are divided by narrower molded separators, which make it easy to trim the unassembled duct to desired length.

Abstract: Supplemental ventilation apparatus is provided for manufactured housing whose window and door openings are tightly sealed when closed. Exterior air is drawn in by the furnace's room air circulating blower through a flexible duct flattened wideningly at its base to fit removably on the upstanding flange of a dampered inlet to the furnace's upper air inlet chamber, which is installed in the narrow top wall surface of the furnace forward of its accessory-mounting portion. When combined with an adequately powered attic exhaust system, negative pressure, which such exhaust system creates in the attic, acts through openings in the ceiling to draw off positive room air pressure. Thus stale room air is withdrawn and exhausted through the attic, without any increase in capacity of the room air circulating blower.

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: For use with a hydrocarbon-fueled furnace whose secondary heat exchanger so cools the combusted gas as to condense much of its water vapor, and having a blower to the flue, a combined trap and drain is provided for the condensate formed both in the heat exchanger and in the flue. At the base of the flue is a standpipe whose upper overflow outlet is connected to a dip tube. Between the level of its lower end and the overflow level is a side inlet into the standpipe, connected to a tube leading downward from the heat exchanger's condenser. When the furnace blower applies both negative pressure to the condenser and positive pressure to the flue, the water levels in the trap and tube adjust to balance out these pressures.

Abstract: A heater rack assembly, of the type which supports an electric heating coil in a pattern of parallel rows in a plane, utilizes double-ended stand-off insulators which are formed wafer-like in the plane. The insulators have, at each end, pairs of hook portions facing each other to provide a throat, which opens into a wire-accommodating slot behind the hook tips, the slot converging toward the center at an angle of 150.degree. or less. Adjacent turns of the coil are to be accommodated within the slot. Its convergence retains within the slot adjacent coil turns which might otherwise escape, requiring for such escape what is in effect a reverse in-plane twisting displacement.

Abstract: A compact secondary heat exchanger, installed above the preliminary heat exchanger in a down draft-type gas burning furnace, so greatly reduces combustion gas temperature as to recover a portion of the latent heat in the water vapor created by burning the hydrocarbon gas.

Abstract: A portable electric baseboard heater includes a unitary structural back plate having a central vertical portion bounded by an integral lower triangular closed box-like structure having a downwardly sloping forward surface and an integral upper triangular portion having an upwardly sloping forward surface, a horizontal top surface and a rear vertical wall in the same plane as the central portion and terminating spacedly thereabove to provide a horizontal opening aft of the upwardly sloping forward surface. An angularly bent or molded plastic liner covers the interior of a portion of the top and upwardly sloping surfaces of the upper triangular portion to form an internal thermally insulative handle accessible through the horizontal opening to permit lifting of the heater. The lower triangular portion serves as a protective raceway for power supply wires to an electric finned tube heater assembly supported by the back plate between the upper and lower triangular portions.

Abstract: A rectangular enclosed electric furnace cabinet, for mobile and modular homes, has a downward blower which draws air downward from an upper wall duct inlet over electric resistance heaters and out through a lower wall duct outlet to the underfloor ducts of the home. A rectangular open frame member, mounting a louvered door, is secured to the cabinet upper wall at its forward end. After closet installation of the cabinet, final wall trim, adjacent to the cabinet sides and the open frame member, may be added. In use exclusively as an electric furnace, a furnace filter is secured beneath the upper furnace inlet by a pair of diagonally-crossed elongated clips. The cabinet is adaptable for use as the indoor unit of a central air conditioner or heat pump by the addition of an A-coil over the upper air inlet; then filters are provided instead on the upper sloping sides of the coil and the elongated clips are utilized to secure insulation sheet to the interior of the cabinet.

Abstract: A defrosting control for a heat pump system utilizes a first temperature sensor mounted to the outdoor coil fan motor windings, a second sensor mounted to sense the outdoor ambient air temperature and a third sensor to sense the refrigerant temperature in the outdoor coil. The control circuitry determines the temperature difference of the first two sensors, representing the fan motor temperature rise, which increases dramatically when the outdoor coil is frosted; if the difference exceeds a selected abnormal temperature rise and the temperature sensed by the third sensor indicates frosting is likely to have occurred, the defrost cycle is initiated. The cycle is terminated when the temperature sensed by the third sensor indicates that all frost is likely to have melted.

Abstract: A suction-liquid heat exchanger for a heat pump is provided by utilizing an inner vessel as a suction line accumulator together with a surrounding high pressure outer vessel which is utilized as a receiver in the liquid line. Heat from the liquid refrigerant in the outer vessel is transferred to the cooler liquid accumulated in the inner vessel to vaporize it, preventing slugs of liquid refrigerant from entering the compressor. The exit and entry ports of the outer vessel are at different levels. This causes a greater amount of liquid refrigerant to remain in the outer vessel on heating mode operation than on reverse flow for cooling, thereby increasing the heat transfer to the accumulator as required for the greater volume of liquid in the suction line gas and compensating for the decreased quantity of refrigerant needed for heating.

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.