Input the known flow rate. You can then toggle through various nominal pipe sizes to find one that meets your design limits—typically keeping velocity under 8–10 feet per second and head loss below 2.5 to 3.0 ft per 100 ft to prevent erosion and noise.
Since McQuay/Daikin doesn’t publish a dedicated standalone sizer today, here are the best alternatives used by experienced chiller technicians: mcquay pipe sizer