Abstract: A pump system includes a pump control module and a cassette with a tube including an anti-siphon valve. A valve operates to control free flow situations, and the valve further has a bypass for priming of the system. The valve includes a bypass mechanism including at least one activation member, such as a button, which moves a movable member for disrupting the seal member of the anti-siphon valve. An alternative valve includes a separate bypass pathway around the anti-siphon valve. In this embodiment, operation of the bypass pathway does not disturb or disrupt the seal of the anti-siphon valve. Operation of the alternative bypass pathway is through a bypass mechanism including a button for movement or disruption of a bypass seal. A cap or other holder opens the bypass for each of the valves for gravity priming.