The present disclosure relates in general to an apparatus and method for priming a liquid or surgical cassette. In one embodiment, an infusion system within the liquid cassette is primed using a forward flow of a liquid and a backward flow of the liquid. The forward flow of the liquid creates a first volume of liquid stored within an infusion conduit, which is connected to an infusion chamber via a first valve. The infusion conduit has an infusion port exposed to a non-liquid environment having a first pressure. A second pressure is created in the infusion chamber that is lower than the first pressure. Opening the first valve causes a second volume of liquid within the infusion conduit to flow over the first valve and towards the infusion chamber. The second volume of liquid is less than or equal to the first volume of liquid.