Extracorporeal blood treatment device and method for operating an extracorporeal blood treatment device

A method for operating an extracorporeal blood treatment device having a multi-flow hydraulic system comprising a plurality of flow paths, a dialyzer bypass conduit, and a bypass valve arranged along the dialyzer bypass conduit, wherein, in an operating mode for a hot disinfection of the multi-flow hydraulic system, the method comprises:

• heating a liquid to a predetermined temperature to form a disinfection liquid;
• opening the bypass valve to form a bypass flow path that bypasses a dialyzer;
• providing the disinfection liquid, at the predetermined temperature, to a multi-flow valve, the multi-flow valve comprising a valve inlet, a first valve outlet, a second valve outlet, a third valve outlet, a valve housing body, a valve body, four bores formed in the valve housing body and respectively forming the valve inlet, the first valve outlet, the second valve outlet, and the third valve outlet, and three passages formed in and passing through the valve body and intersecting in a center of the valve body, wherein the valve body is rotatably mounted within the valve housing body and rotatable to
• a first switching position whereby the valve inlet is closed by the valve body, and
• a disinfection switching position whereby a communication is provided between the valve inlet and each of the first valve outlet, the second valve outlet, and the third valve outlet;
• rotating the valve body from the first switching position to the disinfection switching position;
• and
• simultaneously supplying the disinfection liquid, at the predetermined temperature, from the multi-flow valve, through the first valve outlet, the second valve outlet, and the third valve outlet, and via at least a first bypass conduit and a second bypass conduit to at least a first flow path and a second flow path of the plurality of flow paths of the multi-flow hydraulic system.