Furnace with draft-limiter and ventilation

Furnace wherein there is connected to the exhaust gas duct after said furnace in the flow direction a ventilation opening with a ventilation flap openable in chronological conjunction with the cut-off of said furnace and closable in chronological conjunction with the switching-on of said furnace, and wherein there is further connected to said exhaust gas duct after said furnace in the flow direction a draft-limiter opening with a draft-limiter flap, whereat said draft-limiter flap is prestressed in the direction of a closing position and is to be opened by the pressure difference incident upon it, p1-p2 (flue draft) between the pressure p2 in said exhaust gas duct and the possibly higher pressure p1 on its outer side, in such a way that when the pressure difference exceeds a predetermined value said draft-limiter flap increasingly opens for the purpose of maintaining a predetermined pressure difference, characterized in that said ventilation opening is formed by said draft-limiter opening (16) and said ventilation flap is formed by said draft-limiter flap (20), whereat said draft-limiter flap (20), during an operating pause of said furnace, is held in an open position independently of said pressure difference (p1-p2) prevailing at said draft-limiter flap (20).