A peritoneal dialysis machine is described. The machine comprises: a housing a mechanically actuated piston head (206) extending from a pump actuator (202) housed by the housing, the mechanically actuated piston head (206) positioned to extend towards and away from a fluid pumping cassette (210), the fluid pumping cassette (210) coupled operably to the housing such that a flexible membrane (203) of the fluid pumping cassette (210) faces the piston head (206) a pressure sensor (214) positioned by the housing adjacent to the mechanically actuated piston head (206) and a vacuum chamber formed about the mechanically actuated piston head (206), the vacuum chamber holding a vacuum that sucks the flexible membrane (203) of the fluid pumping cassette (210) onto the mechanically actuated piston head (206) as the mechanically actuated piston head (206) extends away from the fluid pumping cassette (210).
