Dialysis machine and method of operating a balancing chamber system of a dialysis machine

A dialysis machine comprising a dialyzer and a balancing chamber system, the dialyzer comprising a dialyzer inflow and a dialyzer outflow, the balancing chamber system comprising a first balancing chamber, a second balancing chamber, and a control unit, wherein the first balancing chamber has a first balancing chamber first half and a first balancing chamber second half that are separated from one another by a first movable wall, the first balancing chamber first half being provided with a first inflow and with a first outflow, the first balancing chamber second half being provided with a second inflow and with a second outflow, the second balancing chamber has a second balancing chamber first half and a second balancing chamber second half that are separated from one another by a second movable wall, the second balancing chamber first half being provided with a third inflow and with a third outflow, the second balancing chamber second half being provided with a fourth inflow and with a fourth outflow, each of the first, second, third, and fourth inflows and the first, second, third, and fourth outflows is provided with a respective valve that is configured to close or to open the respective inflow or outflow, the first and third inflows are in fluid communication with a source of fresh dialysate, the first outflow is in fluid communication with the dialyzer inflow, the second inflow and the fourth inflow are in fluid communication with the dialyzer outflow, the second outflow and the fourth outflow are in fluid communication with one another so that consumed dialyzate is transferrable from the first balancing chamber second half to the second balancing chamber second half or from the second balancing chamber second half to the first balancing chamber second half, and the control unit is configured to control the valves such that Configuration I is enabled, Configuration II is enabled, or both Configuration I and Configuration II are enabled,

• wherein, according to Configuration I:
• with the first inflow being open and the first outflow being closed, the first balancing chamber first half is filled with fresh dialysate with the second inflow being closed, the second outflow being open, and the fourth outflow being open, the first balancing chamber second half is emptied and consumed dialyzate is conveyed from the first balancing chamber second half of the first balancing chamber into the second balancing chamber second half of the second balancing chamber, and with the fourth outflow being open, the third outflow being open, and the third inflow being closed, fresh dialyzate is conveyed from the second balancing chamber first half to the dialyzer inflow;
• and according to Configuration II:
• with the third inflow being open and the third outflow being closed, the second balancing chamber first half is filled with fresh dialysate with the fourth inflow being closed, the fourth outflow being open, and the second outflow being open, the second balancing chamber second half is emptied and consumed dialyzate is conveyed from the second balancing chamber second half into the first balancing chamber second half and with the second outflow being open, the first outflow being open, and the first inflow being closed, fresh dialyzate is conveyed from the first balancing chamber first half to the dialyzer inflow;
• and wherein the control unit is configured to control the valves such that a volume of fresh dialyzate that is conveyed to the dialyzer inflow is restricted to volumes a volume of between 2 and 15 l/treatment liters per hemodiafiltration treatment.