MULTI-PASS BOILER HEAT EXCHANGE SYSTEM WITH COILED HEAT EXCHANGE TUBES

摘要

A boiler includes a housing defining an enclosed region; a heat exchanger including a plurality of heat exchange conduits at least partially positioned within the enclosed region of the housing; and a burner positioned to deliver products of combustion into the enclosed region of the housing for heat exchange with water or other fluid contained within the plurality of heat exchange conduits. The plurality of heat exchange conduits includes a first helically-coiled heat exchange conduit that at least partially encircles a second helically-coiled heat exchange conduit. Gaps are provided between the first and second heat exchange conduits through which the products of combustion pass.