Abstract: A heat exchanger furnace includes a firebox, a heat exchanger housing in communication with the firebox for receiving combustion gases therefrom, and a plenum housing surrounding the heat exchanger housing so as to define a plenum chamber therebetween. A plurality of baffles are supported in vertically spaced apart relation within the heat exchanger housing, which baffles include peripheral edges disposed in clearance relation from the housing sidewalls whereby hot combustion gases rising within the heat exchanger housing are directed outwardly adjacent the heat exchanger sidewall for increased heat transfer to the plenum chamber. Exhaust tubes at the top of the heat exchanger housing may be directed through the plenum chamber for providing additional heat transfer surfaces therein. The firebox may have a frusto conical shaped sidewall whereby the combustion surface area may be adjusted with the level of fuel in the firebox.

Abstract: A heat exchanger furnace includes a firebox, a heat exchanger housing in communication with the firebox for receiving combustion gases therefrom, and a plenum housing surrounding the heat exchanger housing so as to define a plenum chamber therebetween. A plurality of baffles are supported in vertically spaced apart relation within the heat exchanger housing, which baffles include peripheral edges disposed in clearance relation from the housing sidewalls whereby hot combustion gases rising within the heat exchanger housing are directed outwardly adjacent the heat exchanger sidewall for increased heat transfer to the plenum chamber. Exhaust tubes at the top of the heat exchanger housing may be directed through the plenum chamber for providing additional heat transfer surfaces therein. The firebox may have a frusto conical shaped sidewall whereby the combustion surface area may be adjusted with the level of fuel in the firebox.