a unit for heating the water used in the heating, ventilation, and hot-water supply systems of buildings and other types of structures. Cast-iron sectional hot-water boilers, which heat the water to temperatures no higher than 115° C, are used for heating residential and public buildings. The heat-generating capacity of these boilers does not exceed 1.5 gigacalories per hour (1 gigacalorie per hour = 1,163 megawatts), and the pressure does not exceed 0.4 meganewtons per sq m (MN/m2), or 4 kilograms-force per sq cm (kgf/cm2). There are several different cast-iron hot-water boiler designs, but they are all assembled from separate, specially shaped tubular sections. The inner chambers of each section, in which the heated water circulates, are joined together with sleeves on the top and bottom during the assembly of the boiler. A furnace grate and combustion chamber (sometimes externally fired) are placed beneath the two symmetrically positioned assembled sets of sections. Various types of fuel may be used in cast iron hot-water boilers.
Three types of hot-water boilers are manufactured from standardized sections: the KCh-1, KCh-2, and KCh-3 models, with a nominal heating surface ranging from 7.1 to 156 m2. Steel hot-water boilers are designed to heat water up to 200° C under pressures of up to 2.5 MN/m2 (25 kgf/cm2). These boilers have heat-generating capacities of 4, 6.5, 10, 20, 30, 50, 100, and 180 gigacalories per hour. Hot-water boilers rated at 30 gigacalories per hour and higher are installed in block and district boiler rooms, as well as in central heating and power plants, to handle peak heating loads during the winter. The most commonly used steel hot-water boilers with a high heating capacity are gas-mazut boilers. These boilers are equipped with completely shielded combustion chambers and have convection surfaces.
G. E. KHOLODOVSKII