A dialysis machine that includes a valve body defining a pressure passage and a sealing cap disposed at a first end of the valve body such that the sealing cap closes off the pressure passage at the first end of the valve body. The sealing cap has a deformable area configured to deform outwardly away from the valve body when pressurized fluid is introduced into the pressure passage of the valve body. The sealing cap is configured so that, when a dialysis fluid cassette is disposed in a cassette compartment of the dialysis machine and pressurized fluid is introduced into the pressure passage of the valve body, the deformable area obstructs a fluid channel of the dialysis fluid cassette to control dialysis fluid flow therethrough.