Patent ID: 7614366

Claim:
A water heater comprising: an outer tank having a cold water inlet aperture, a hot water outlet aperture, a heat input aperture, a plurality of intermediate hot gas output apertures, an intermediate hot gas input aperture and a plurality of exhaust apertures; a source of heat adapted to the heat input aperture; a firing chamber within the outer tank, the firing chamber interfaced at a first end to the heat input aperture; a plurality of heat exchange tubes operably coupled at a first end to a second end area of the firing chamber and the plurality of heat exchange tubes operably coupled at a second end to the plurality of intermediate hot gas output apertures; a heat transfer chamber operably coupled at a first end to the intermediate hot gas input aperture and operably coupled at a second end to a first end of a second plurality of heat exchange tubes, a second end of the second plurality of heat exchange tubes operably coupled to the exhaust apertures; a manifold having two chambers, a first manifold chamber adapted to pass hot gases from the plurality of intermediate hot gas output apertures to the intermediate hot gas input aperture and a second manifold chamber adapted to pass exhaust gases from the plurality of exhaust apertures to an exhaust coupling; and a condensing chamber jacket enclosing the heat transfer chamber and the second plurality of heat exchange tubes, the condensing chamber jacket fluidly interfaced near a first end to the cold water inlet aperture and, the condensing chamber jacket having at least one warm water aperture near a second end of the condensing chamber jacket, the warm water apertures passing pre-heated water from within the condensing chamber jacket into the outer tank.