R. L. Deppmann Company Monday Morning Minutes addressed corrections to system GPM (gallons per minute) and system friction head during the last three weeks. Today we look at the pump selection. Centrifugal pump curves and the brake horsepower required changes depending on the fluid. In HVAC design we normally assume water is the pumped fluid. There are many times when the assumption is water, since there is no fluid mentioned on the schedule, yet we find a glycol makeup unit attached to the system.