The steel boilers Pirolambda with a thermal input of 25, 31 and 45 kW are fed with wood with moisture below 25%. Through the principle of pyrolysis fuel is burned completely. The spacious freplace makes it possible to feed the boiler with pieces of wood of length up to 550 mm. A load of wood lasts at least up to 5 hours and it is possible to increase it to all day by working with lower temperatures. The boiler can maintain the embers up to 12 hours and the management of the boiler is controlled by the lambda sensor, installed as a standard device, which acts automatically adjusting the actuators of the registers of primary and secondary air and the speed of the smoke aspirator. The boiler is easy to manage, and is provided with a color display that ensures an easy use of the boiler.