The inner part—a fireplace insert—of the two wall weldment functions as an independent heater. The insert comprises of a combustion chamber—firebox—fitted with fireclay bricks, with a grate on the bottom, closed at the front with a see-through tempered glass stoking door. Adjustable openings on the door frame bring in secondary air which ensures thorough burn of the developed wood gas.
The firebox is separated from the smoke chamber by a throat with a damper. The smoke chamber carries the flue gases to the chimney. The ash pan is located in the lower part underneath the grate. The outer wall finishes with a cover on the top. This cover is open during use to strengthen the stack effect: the cold air is drawn from the bottom and flows upwards to the room.
The water exchanger design includes a hot-water exchanger placed on the back side of the firebox. The rear outlet passes through the centre of the exchanger.