Abstract: A furnace heat exchanger assembly includes first and second heat exchanger halves. The first heat exchanger half includes a first half of an exhaust channel and an inner joint flange half at an end thereof. The second heat exchanger half includes a second half of the exhaust channel and an outer joint flange half at an end thereof having first and second capturing tabs. The first and second heat exchanger halves are coupled together such that the first and second capturing tabs substantially overlap the inner joint flange half to form a joint flange.

Abstract: A furnace unit comprising a mounting panel, a burner assembly and a heat exchanger. The burner assembly is mounted to one side of said mounting panel, the burner assembly having at least one burner located therein. The heat exchanger is mounted to an opposite side of said mounting panel. The heat exchanger has at least one continuous combustion tube, wherein said combustion tube includes at least a first pass and a second pass. The first and second passes are interconnected by a curved pass of the combustion tube. One end of the combustion tube has a first opening that is coupled to the burner assembly. The combustion tube has at least three zones.

Abstract: A furnace unit that comprises a burner assembly having at least one burner located therein and a heat exchanger having at least one continuous combustion tube. One end of the combustion tube has a first opening that is coupled to the burner assembly. The combustion tube has at least three zones. A first surface of the first zone has a first non-straight angle with a second surface of the second zone. The second surface has a second non-straight angle with a third surface of the third zone. The first zone is nearest of the three zones to the burner assembly and the second zone is in-between the first zone and the third zone. The first, second and third zones are within a flame length configured to be emitted from the burner.

Abstract: A clamshell heat exchanger for use in a gas-fired direct combustion furnace. The exchanger comprises a first clamshell half and a second clamshell half that when joined with the first clamshell half forms a passageway having an inlet and an outlet. The passageway includes a U-bend located between the inlet and the outlet, wherein the U-bend includes a re-entrant sectional profile.

Abstract: A furnace heat exchanger assembly includes first and second heat exchanger halves. The first heat exchanger half includes a first half of an exhaust channel and an inner joint flange half at an end thereof. The second heat exchanger half includes a second half of the exhaust channel and an outer joint flange half at an end thereof having first and second capturing tabs. The first and second heat exchanger halves are coupled together such that the first and second capturing tabs substantially overlap the inner joint flange half to form a joint flange.

Abstract: A furnace unit that comprises a burner assembly having at least one burner located therein and a heat exchanger having at least one continuous combustion tube. One end of the combustion tube has a first opening that is coupled to the burner assembly. The combustion tube has at least three zones. A first surface of the first zone has a first non-straight angle with a second surface of the second zone. The second surface has a second non-straight angle with a third surface of the third zone. The first zone is nearest of the three zones to the burner assembly and the second zone is in-between the first zone and the third zone. The first, second and third zones are within a flame length configured to be emitted from the burner.

Abstract: A clamshell heat exchanger includes a first clamshell half and a second clamshell half. When joined, the first and second clamshell halves form a passageway having an inlet and an outlet. The passageway has a height and a depth. A ratio of the height to the depth is about 0.5 or less. The heat exchanger has an efficiency of at least about 70%.

Abstract: A multi-position furnace is provided that can be positioned for downflow operation, upflow operation, left horizontal flow operation, or right horizontal flow operation without major modifications in the field. The furnace includes a multi-position condensate draining system which facilitates draining of condensate fluid regardless of the orientation of the furnace. The condensate draining system includes a header box and an exhaust manifold, each of which includes a number of drain ports that allow fluid condensing from combustion gasses to be drained regardless of furnace orientation. A trap is configured for attachment to the furnace in any one of four different positions, and receives condensate fluid from the header box and from the exhaust manifold. An air intake manifold is specially configured to maintain a low profile, thereby facilitating use of the multi-position condensate draining system.

Abstract: A combination water heating and space heating apparatus includes a water heating unit and a space heating unit releasably coupled with the water heating unit. The water heating unit has a water storage tank and a helically wound tubular heat exchanger inside the tank for exhausting products of combustion from a combustion chamber located in a top part of the tank and for transferring heat from the products of combustion to the surrounding water. The space heating unit is an air handler with an hydronic heat exchanger coil and a blower for blowing air over the coil. Hot water is supplied from the tank to the coil and is returned to the tank by means of a water circulation pump located in the space heating unit. Air blown over the coil is heated by the hot water flowing over the coil.

Abstract: An improved combustion chamber for a condensing furnace comprising an elongated cast body having a mixing chamber for receiving fuel and air and an expansion chamber communicating with said mixing chamber, a fuel inlet in said body communicating with said mixing chamber, an air inlet in said body communicating with said mixing chamber and means for igniting the air fuel mixture in said mixing chamber, the fuel inlet and the igniting means being opposed to one another to enhance the ignition of the fuel and air in the mixing chamber. An important feature of the invention is the critical ratio of the transverse cross sectional area of the expansion chamber to the transverse cross sectional area of the mixing chamber for maintaining continuity of operation. Such ratio should be about 2/1 to 2.4/1. In a preferred form of the invention, the igniting means is a spark plug and the spark plug opening into the mixing chamber is co-axial with the fuel inlet.

Abstract: A condensing furnace utilizing a pulsating combustion process discharges flue gas and condensate from the furnace through a flue gas conduit. A drain leg assembly is coupled to the flue gas conduit for effectively separating the condensate from the flue gas, whereby the flue gas is discharged to the flue gas vent and the condensate is discharged to a drain line. The drain leg assembly includes tubular body means having a flue gas outlet at the upper end thereof and means defining a condensate reservoir at the lower end thereof. A vent pipe within the tubular body means and having a bore smaller than that of the tubular body communicates at one end to a condensate outlet means, and the other end of the free end of the vent pipe extends toward the bottom of the tubular body, but is spaced therefrom. The normal level of condensate collected in the tubular body means is above the bottom of the vent tube so as to assure separate discharge of flue gas and condensate from the drain leg assembly.

Abstract: A gas furnace of the pulsating combustion type having improved sound reduction means comprising an exhaust decoupler body adapted to receive pulsating exhaust gases from the combustion chamber, the exhaust decoupler body having an opening with a silencer tube fixed therein, the silencer tube having an inlet opening receiving the pulsating exhaust gases from the combustion chamber and the silencer tube extending into the exhaust decoupler body and having an outlet opening in the mid-region of said exhaust decoupler body. Outlet means in the form of slots are provided in the length of the silencer tube within the exhaust decoupler body. The silencer tube cooperates with the exhaust decoupler body to dissipate the energy of the pulsating exhaust gases.Resonator means are coupled to the exhaust pipe which connects the combustion chamber to the silencer tube.