Disclosed is a filling and recirculation device of a fluid conducting system for blood treatment which has a fluid connector and a three-dimensional four-way valve with a first valve plane on which an inlet connector for the fluid container, an arterial line connector, and a valve-internal coupling connector are arranged and a second valve plane on which an outlet connector and a venous line connector are arranged. The venous line connector is permanently connected with the valve-internal coupling connector. A manually operable valve rotary piston of the four-way valve has a first control section assigned to the first valve plane and a second control section assigned to the second valve plane.