Modern gas boilers for central heating, as well as gas hot water heaters are made of the so-called. closed combustion chamber. Means, that such a device can be installed in any room, which is not equipped with a flue gas pipe, nor in the ventilation area. The exhaust fumes, and the air needed to burn the gas is supplied by a concentric pipe leading from the furnace to the outside through the walls or roof of the building.
