Abstract: Connecting arrangement for a heating boiler, in whose water-bearing sheet-steel housing is arranged an installation casting consisting of a combustion chamber and fuel-gas ducts.For having a good and simple connection between the sheet-steel housing and the installation casting the improvement consists in that the front and rear wall of the sheet-steel housing are provided with an access opening and the opening edges are bent in the form of a collar, the inside diameter of the collar being rather smaller than the outside diameter of the seating faces of the installation casting and the front and rear wall being connected to the seating faces by a press fit.