Abstract: A damper interlock mechanism comprising a housing including first and second apertures, a damper assembly pivotably mounted in the first aperture and a swing out unit pivotably mounted in the second aperture for pivotal movement between a first shipping position and a second operational position. The mechanism also includes an actuator for actuating the damper, and a damper control rod having a first end operationally connected to the actuator, a second end operationally connected to the damper assembly, and an intermediate portion. The intermediate portion includes means for interlocking the damper control rod with the swing out unit when the swing out unit is in the shipping position.

Abstract: A tube arrangement for a tube-type heat exchanger. The tube arrangement provides for the location of the tubes in the upper portion of the drum defining the combustion chamber of the heat exchanger. In one embodiment, four heat exchange tubes are provided, with two of the tubes disposed such that the axial center line of the tube lies across the horizontal center line of the heat exchanger drum, and with two tubes disposed entirely above the horizontal center line of the drum.

Abstract: A premix furnace burner for a gas combusting furnace. The furnace burner includes a premix chamber and a burner plate assembly. The burner plate assembly is comprised of a burner plate with a plurality of relatively small apertures for the passage of a mixture of combustible gas and air and an annular ring for retaining the burner plate. The annular retaining ring determines the capacity of the furnace burner by appropriately sizing of the opening in the annulus of the retaining ring to sealingly overlay a selected portion of the burner plate apertures. The retaining ring further secures the burner plate in the correct operational position while simultaneously permitting the burner plate to expand and contract in response to temperature changes induced by combustion of the gas and air mixture.