Cast iron heating boilers are central heating boilers designed for heating private houses, small apartment buildings, offices and shops. Cast iron boilers can use any solid fuel as fuel – wood, sawdust briquettes, coal. Cast iron boilers can also burn wetter firewood. This will not damage the boiler overall, it may only create additional tar deposits on the boiler walls.
Cast iron is an alloy of iron and carbon. Cast iron heating boilers are not affected by corrosion caused by combustion processes, therefore it is resistant to deformation and has high wear resistance – with proper maintenance, the service life can reach up to 30 years.
The construction of cast iron boilers has a shorter flue gas path, which does not give as high boiler efficiency as steel heating boilers. The efficiency of cast iron boilers ranges from 65-75%. Cast iron boilers have a high outgoing flue gas temperature, so it is not necessary to line the chimney and there are no high requirements for chimney draught. Cast iron heating boilers are made up of sections, so if necessary, a damaged section can be replaced or the boiler's output can be increased. Cast iron boilers work in both gravity and forced circulation systems, and their installation costs will be cheaper, as less control fittings are required – the boiler installation and connection does not require creating a complex heating circuit, only one pump and one four-way valve are needed. Cast iron heating boilers can heat areas from 70 up to 500m2. But like any solid fuel boiler, it is advisable to install it together with a buffer tank. The tank makes it possible to ensure a more even temperature in the house, so that it is also warm between firing periods. The operating principle of the boiler together with a buffer tank is that the boiler fires at nominal output, at full power, and the excess heat that is not needed for room heating at that moment is stored in the tank; when firing stops, heat is taken from the tank.