Patent ID: 7290503
Filing Date: 2007-11-06
Classification: F24H,Y02B

Abstract:
1. A fuel-fired heating appliance comprising: a tank for holding water to be heated; first and second spaced apart plenum structures external to said tank; a heat exchanger disposed within said tank and including a tubular first pass member, a dividing structure separating said first pass member into a first longitudinal portion and a second longitudinal portion communicating with the interior of said second plenum structure, at least one tubular second pass member having a first end communicating with the interior of said first longitudinal portion of said first pass member and a second end communicating with the interior of said first plenum structure, and at least one tubular third pass member having a first end communicating with the interior of said first plenum structure and a second end communicating with the interior of said second longitudinal portion of said first pass member; and a combustion system operative to flow hot combustion gas sequentially through said first longitudinal portion of said first pass member and then into said first plenum structure via said at least one second pass member, from said first plenum structure into said second longitudinal portion of said first pass member via said at least one third pass member, and then into said second plenum structure from said second longitudinal portion of said first pass member.