Household double-presusre boilers allow to regulate the efficiency in wide ranges (the efficiency is about from 40% to 100%). What should you do if you need more efficiency of heating. For example you live in a large private house with several rooms for the guests, and in spring when 40% is enough for the heating of the whole house, so you will not have to heat the bare rooms.
Of course, you can use the usual household boiler – when reducing the heat consumption below 40% from rated power, the boiler will work at intermittent operation (it will heat the water in heaiting system until the temperature will not rise up to 1°С). Such method is not economical as the gas consumption at constant switching on and off is increased and its operational life is reduced.
In order to solve this problem, it is necessary to install the cascade from 3-4 heating boilers of less capacity. Their capacity is enough for house heating in severe frost. When using cascade, consisting of 2 boilers, the minimum capacity of such small boiler room is 20%, and when using 4 boilers – 10%.
Cascade of the boilers are used not ony in private houses, combined 16 and more boilers into one cascade, but also at enterprise, public building or residential complex. The main advantages of such boiler room are economical operation, reliability