The generator has an evaporator-passage heating surface (8) formed from evaporator pipes (6) and a superheater-heating surface (12) formed from superheater pipes (10) that are flow-medium sided downstream to the pipes (6). The surfaces are arranged in a heating gas channel (4). A water separating unit (30) is integrated in overflowing pipe sections (20) that connect the pipes (6) with the pipes (10) in a flow medium sided manner.
