A centrifugal pump assembly includes an electrical drive motor (4, 6), an impeller (14) which is driven by the drive motor and a pump casing (12) surrounds the impeller and including two branches (27, 32, 34). A movable valve element (18) is arranged in the pump casing and is movable between two switching positions, in which the flow paths through the two branches (27, 32, 34) are opened to a different extent. The valve element (18) is configured and arranged in the pump casing (12) such that it separates a suction chamber (24) which is connected to a suction side of the impeller (14) from a delivery chamber (26) which is in connection with the delivery side of the impeller (14). The valve element (18) is mechanically and/or hydraulically coupled to the drive motor (4, 6) for at least a movement between the two switching positions.