Central heating boiler

In a central heating boiler for solid fuels according to the invention, the primary and secondary air is automatically regulator-controlled and enters the boiler at the level of the fire bed (6). The primary air guidance (a) takes place horizontally through the fire bed (6). The secondary air guidance (b) takes place through a preheating vertical shaft (10) to the upper region of the filling shaft (1) and from there, directed downwards, through the rear region of the fire bed (6) to the inlet opening (7) and through the stone nozzle (11) to the post-combustion chamber (2). By means of these mutually adapted functional sequences, clean and virtually smokeless complete combustion is achieved.