Hot air furnace

Abstract

A compact, high efficiency hot air furnace including a heat exchanger assembly located in a heat exchange chamber through which comfort air is passed to be heated. The heat exchanger assembly includes a drum-like combustion member located such that its axis extends across the flow path of comfort air. A supplementary heat exchanger or condenser is located a spaced distance from the combustion member and is disposed in the comfort air flow path upstream from the combustion member. A transfer channel extends from one end of a cylindrical wall forming part of the combustion member and communicates combustion by-products to the condenser. Heat exchange fins are mounted to the cylindrical wall of the combustion member and along a wall of the transfer member. A diffuser located within the combustion member is cup-shaped and includes a wall portion positioned between a burner and a transfer channel opening which prevents the burner flame from extending into the transfer channel. In addition, a side wall portion of the diffuser forces the combustion by-products to take a circuitous path thereby increasing the dwell time of the combustion products and urging them to flow in close proximity to an inside surface of the cylindrical wall section to increase the amount of heat transferred to the combustion chamber wall.