The exclusivity and high capacity of the Famar heat exchanger, which is optimized for each boiler, brilliantly avoids the typical problem of all water boilers that use woody biomass: the deposition of combustion residues (such as creosote, pitch, and others) on cold surfaces. This layer blocks heat exchange by 5% for each millimeter deposited, slows down combustion, lowers thermal efficiency, and is difficult to eliminate. The Famar heat exchanger has fins welded to the contact surface, making the structure a dry chamber (patented system) that becomes incandescent when gases pass through, exceeding the incandescent temperature of unburned smoke particles and distillates, which are further burned. These combustion deposits burn and produce additional energy, transforming into easily removable ash. The boiler efficiency remains constant throughout its life, from the first to the last day of use, as no creosote or unburned deposits accumulate in the heat exchanger, allowing the combustion of any type of wood or biomass.