Abstract: There is disclosed a furnace having an air flow path for heated air and combustion products that passes through a condensing heat exchanger. Condensate forming in regions of negative and positive pressure is separately conducted to a unitary condensate trap of minimal vertical height incorporating therein separate traps for handling the high and low pressure gaseous environments. The condensate is drained through a common outlet port into the atmosphere or into a drain pipe.

Abstract: A pair of sealing skirts join the inducer to the collector box of a condenser induction furnace, and accommodate offset in positions of the inducer inlet opening and the collector box outlet port. The two mating skirts are congruent and of generally triangular shape. A ridge or lip of one fits a groove on the other to form an airtight gasketless seal.

Abstract: In a furnace of the type having a blower shelf with a blower attached to one surface thereof and a heat exchanger unit located proximate a second surface thereof, and the heat exchanger unit being reversibly attachable to the blower shelf, the improvement comprising: a retaining structure unitary with the back panel of the heat exchanger; and a structure which mates with the retaining structure and is unitary with the blower shelf. The retaining structure and mating structure function jointly to retain the back panel of the heat exchanger unit perpendicular to and proximate the blower shelf.

Abstract: In a multi-poise furnace having multiple parallel heat transfer stages, each stage having superimposed flow passages lying in a common plane. The last passage in each stage containing laterally-disposed indentations in opposed side walls for increasing the heat transfer surface area, and the walls of the last passage being further configured to conduct any condensate formed in the heat exchanger out of the exit region of the exchanger, regardless of the furnace orientation.

Abstract: A coupling box for a condensing furnace having primary and secondary heat exchangers places the discharge ports of the primary heat exchanger in fluid communication with the inlet ports of the condensing heat exchanger. A baffle in the coupling box directs the flow of flue gas evenly therein to maintain temperature equilibrium so that water vapor does not condense in the coupling box.

Abstract: An inducer (40) for causing a flow of combustion air into and gases of combustion through and out of a furnace (10) of the condensing type. The inducer is intended for use, without modification of its design or size, in a series of furnaces of the same basic design but having different heating capacities and therefore different requirements for flow through the induction flow path. The furnace design is such that a given furnace is capable of operation so as to provide a flow of air to be heated that is either up, down or horizontal with only minor field modification on installation. The inducer has two discharges (43), only one of which is used in a given installation. The other discharge is blocked with a plug (61) of special configuration that can vary the output of the inducer to ensure optimum flow of combustion air into and gases of combustion through and out of the furnace.

Abstract: There is disclosed a furnace having an air flow path for heated air and combustion products that passes through a condensing heat exchanger. Condensate forming in regions of negative and positive pressure is separately conducted to a unitary condensate trap of minimal vertical height incorporating therein separate traps for handling the high and low pressure gaseous environments. The condensate is drained through a common outlet port into the atmosphere or into a drain pipe.