This manual explains the features and operations of the VFDC-
4100 controller which is specifically designed for Pressure Booster
Pump Systems. The VFDC-4100 controller is capable of maintaining
a constant discharge pressure by adjusting the speed of up to 4
Variable Frequency Drives (VFDs), one VFD and up to 3 across the
line (ATL) starters, or one Jockey pump and up to 3 main pumps.