Safeguard for furnace draft system

Draft safeguard apparatus for use in a multi-poise furnace having an inducer housing for receiving a flow of flue gas from the furnace heat exchanger, said apparatus including:

• an inducer fan assembly mounted upon said inducer housing and being arranged to draw flue gases from said heat exchanger into said inducer housing,
• an elbow mounted upon said housing apart from said inducer fan assembly, said elbow having a first linear inlet section that passes into said housing and a linear outlet section that is connected to a flue pipe,
• an elongated gas sensor housing mounted upon the inlet section of said elbow, said sensor housing having a first opening at one end thereof for placing the sensor housing in fluid flow communication with the inlet section of said elbow and a second opening at the other end thereof that communicates with the surrounding ambient whereby air and gas can flow between the openings, and
• a limit switch mounted adjacent to said second opening for sensing the temperature in the flow moving through said sensor housing, said limit switch being cycled when the flow temperature exceeds a given limit.