YTKY3G (232-930 KW) Series Solid Fuel Central System Heating Boiler 4 Covers - Half Cylindrical - Pipe - 3 Pass Central System Heating Boiler USAGE AREAS Mass Housing Heating FUEL TYPES Wood, Coal For high efficiency and lower fuel consumption, start using 3-Pass Technology. Increase heat efficiency and reduce fuel costs. Increase the efficiency of the mixing arm Use the fuel more efficiently ... You can use Pellet fuel, which cannot be used in the standard system, with this add-on. Downloadable Content File Name Download link Solid Fuel Central System Heating Boiler Download File