The high-performance industrial boiler is produced with a stress-free welded construction. The thermally insulated door at the front swings out completely permitting free access for cleaning all the boiler flues. The boiler is constructed in accordance with the natural combustion process of the fuel wood. The gasification combustion chamber built on a direct pass principle is fitted with a variable, ceramic (replaceable) radiator roof cladding. High combustion temperatures and a long furnace duration of the gases is the guarantee for a clean burning process. Gilles industrial boilers operate at 93% efficiency. Fuel is fed automatically into the industrial boiler.