High efficiency furnace with secondary heat exchanger

In a domestic forced-air furnace having a hydrocarbon fuel burner, the improvement comprising:

• heat exchanger means for receiving the products of combustion from said burner, said heat exchanger means being arranged to extract sufficient heat from the combustion products to cause the formation of condensate therein and being further arranged to pass substantially all of said condensate therethrough;
• induced draft blower means connected to said heat exchanger for receiving the combustion products and condensate therefrom, said blower being arranged to pass all of the combustion products and condensate therethrough;
• and
• means for connecting the heat exchanger means to the blower means to pass all of the combustion products and condensate from the heat exchanger means to the blower means;
• and
• condensate separating means connected to said blower downstream thereof for receiving the condensate and combustion products discharged by said blower means and separating liquid condensate from the gaseous products of combustion.

In a domestic furnace having heat exchanger means for causing sufficient heat to be extracted from products of combustion formed therein to cause formation of liquid condensate therein, and fluid moving means downstream of said heat exchanger means for causing flow of the products of combustion therefrom, the improvement comprising:

• means defining a condensate discharge positon downstream of said fluid moving means;
• and
• means for causing flow of substantially all of said liquid condensate formed in said heat exchanger means through said fluid moving means to said condensate discharge position, including
• means for connecting the heat exchanger means to the fluid moving means, to pass all of the combustion products and condensate from the heat exchanger means to the fluid moving means.