During operation, particles of dirt, sand, scale, and rust accumulate inside the boiler. The filters, if installed, could not clean them. This adversely affects the condition of the heating elements, the internal walls of the boiler, as well as temperature control and water quality. If the boiler is heavily polluted, the water heating time and energy consumption increase. Overheating of the heating elements with their further burnout is possible. Therefore, flushing the boiler is necessary. For high-quality functioning of the boiler, service cleaning must be performed once a year.