A mover combination (226) for moving and positioning a device (34) includes a mover (328) that defines a fluid passageway (370) and a circulation system (330) having a passageway inlet (374) and a passageway outlet (376). The circulation system (330) directs a circulation fluid (378) into the fluid passageway (370). The circulation system (330) can include a liquid/gas separator (384) that is in fluid communication with the fluid passageway (370). With this design, the plumbing for the liquid (378A) and the gas (378B) can each be optimized. Additionally, the circulation system (330) can include a pressure control device (388) that controls the pressure of the circulation fluid (378) in at least a portion of the fluid passageway (370). With this design, the pressure control device (388) controls the pressure of the circulation fluid (378) near the fluid passageway (370) so that the temperature of the circulation fluid (378) at the passageway outlet (376) is approximately equal to the temperature of the circulation fluid (378) at the passageway inlet (374). Moreover, the circulation system (930) can include a pump assembly (980) that directs the circulation fluid (978) into the passageway inlet (974), and a pressure control device (996) that precisely controls a state of the circulation fluid (978) near the passageway inlet (974). With this design, the phase of the circulation fluid (978) at the passageway inlet (974) can be precisely controlled without restricting the flow of the circulation fluid (978).