Multiple fueled boiler (wood, natural gas, oil) with stainless steel combustion chamber for civil heating purposes. Separate boilers and independent smokestacks. Wood gasification technology combustion chamber style with vertical reverse flame. Combustion air sucked by the smoke drafting fan with air stream distribution and adjusting box on the intake side. THREE EFFECTIVE SMOKE RACES FOR HIGH THERMAL EXCHANGE RATE. Oil combustion chamber with "dry walls" arrangement. Power modulating operation for low condensation and tar levels. Integral outer case. Outer door, vertical axle drafting fan arrangement with double cooling stage.