Condensing boiler

Abstract

The invention provides a condensing boiler 100 including a heat exchanger 160, the heat exchanger including at least one fluid flow cassette 162a, 162b, 163a, 163b, 164a, 164b, each cassette comprising first 181 and second 182 sheets, wherein at least the first sheet has corrugations 185, 186, 187 along a length of the sheet so as to form a number of grooves extending across a width of the sheet, wherein the second sheet is attached against the first sheet so as to enclose the grooves to form a number of fluid flow passageways 193 extending across a width of the cassette in between the first and second sheets, and wherein the cassette is substantially curved across its width such that the fluid flow passageways are substantially curved along their length. The invention also provides a method of manufacturing a heat exchanger or condensing boiler.

Dependencies are inferred from the claim text.