Abstract: A rotationally cast molded article, such as a pump housing or a tank liner, is disclosed. The molded article has reinforced access openings which form flanges. The flanges are reinforced by embedded metal plates having an array of threaded metal sleeves which serve to mount the plates in the mold and which serve as threaded connectors for flanged fittings associated with the access openings.

Abstract: A swimming pool or spa heater unit having a heat exchanger manifold designed to permit the use of direct plastic piping connections to the manifold header. The manifold is principally characterized by a header end having an inlet port and outlet port located on a level below the manifold inlets and outlets communicating with the heat exchanger. The inverted arrangement of the header ports relative to the manifold inlets and outlets to the heat exchanger permits unreturned water in the unit heated by residual heat from the heater to form a temperature gradient therebetween which prevents the temperature of the water at the header connection from reaching a level incompatible with the use of direct plastic piping connections. The manifold is also integrally provided with weirs which serve to provide dry-fire protection for the heater.

Abstract: A valve assembly is disclosed which includes a first valve disc positionable against a valve seat in response to sensed temperature. The first valve disc includes a central aperture which is closeable by a second valve disc held in position by a compression spring. The second valve disc is displaced in response to liquid pressure. The valve assembly thereby provides for the independent control of flow through a passageway in response to temperature and/or pressure. The valve assembly has a particular application in conjunction with the control of bypass flow for a continuous flow liquid heater.

Abstract: An insulated firebox is disclosed which forms a portion of the combustion chamber of a pool heater and which is adapted for reducing the emission of smoke and odor from the firebox into the atmosphere. The firebox is comprised of insulation material which defines a combustion chamber enclosed by the insulation on its vertical sides. The insulation contains organic materials capable of resulting in the generation of smoke or odor. A liner extends substantially continuously about the insulation and seals the vertical sides of the combustion chamber from the escape therethrough of the organic materials contained by the insulation. The organic materials are thus directed into the combustion chamber, where the higher temperature will result in more complete combustion of the materials with a consequent reduction or elimination of the potential smoke or odor.