Condensate drainage system for an outdoor condensing furnace

An improved condensing furnace of the type having a burner, a primary heat exchanger, a condensing heat exchanger and a blower for causing air to flow over the primary and condensing heat exchangers to be heated thereby, comprising:

• a drain line connected to an outlet of said condensing heat exchanger for conducting the flow of condensate to a discharge site;
• wherein said drain line passes through a space that is maintained by the furnace heat of combustion at temperatures above freezing during heating operation and further
• wherein said drain line passes through a flue pipe.

A method of draining condensate from a condensing furnace located outdoors and having a burner, a primary heat exchanger, a condensing heat exchanger and a fan for causing air to flow from a return air duct to the primary and condensing heat exchangers to be heated and then to a supply air duct, comprising the steps of:

• providing a drain line for conducting condensate from said condensing heat exchanger to a discharge, routing said drain line through a space designed to be maintained by the furnace heat of combustion at a temperature above freezing during heating operation and routing said drain line through said supply air duct.

A method of draining condensate from a condensing furnace located outdoors and having a burner, a primary heat exchanger, a condensing heat exchanger and a fan for causing air to flow from a supply air duct to the primary and condensing heat exchangers to be heated, comprising the steps of:

• providing a drain line for conducting condensate from said condensing heat exchanger to a discharge site and routing said drain line through a space designed to be maintained by the furnace heat of combustion at a temperature above freezing during heating operation and including the steps of providing a drain pan in a compartment containing said primary heat exchanger and conducting the flow condensate to said drain pan, and placing said drain pan in direct contact with said primary heat exchanger such that the heat from said heat exchanger causes said condensate to vaporize.

A method of draining condensate from a condensing furnace located outdoors and having a burner, a primary heat exchanger, a condensing heat exchanger and a fan for causing air to flow from a supply air duct to the primary and condensing heat exchangers to be heated, comprising the steps of:

• providing a drain line for conducting condensate from said condensing heat exchanger to a discharge site and routing said drain line through a space designed to be maintained by the furnace heat of combustion at a temperature above freezing during heating operation;
• wherein said drain line is routed through a flue pipe.