Blood treatment systems and methods

A system for cleaning a fluid flowpath connected to a pair of diaphragm pumps comprising:

• a first and a second diaphragm pump, each pump comprising a pumping chamber separated from an actuation chamber by a flexible diaphragm;
• each pump actuation chamber selectively connectable by action of a controller to a source of positive or negative pressure;
• a first fluid flowpath connecting an inlet of the first pump through a first inlet valve with an inlet of the second pump through a second inlet valve, and a second fluid flowpath connecting an outlet of the first pump through a first outlet valve with an outlet of the second pump through a second outlet valve;
• the inlet and outlet valves each comprising a valve selectively connectable by action of the controller to the source of positive or negative pressure;
• wherein the controller is configured to direct an application of negative pressure to the diaphragm of the first pump when emptied of fluid and an application of positive pressure to the diaphragm of the second pump when filled with fluid while the first and second inlet valves are open and the first and second outlet valves are closed to clean the first fluid flowpath OR while the first and second inlet valves are closed and the first and second outlet valves are open to clean the second fluid flowpath.