PFC stands for piston flow compensated. It is a piston pump with a valve that controls the flow and pressure of the pump. The pump mounts the the pto gear box supply to it is gravity fed from the hydraulic reservoir. The compensator or control valve mounts to the side of the pump. On one side there is two studs with jam nuts on them . High pressure standby is closest to pump. Clockwise increases pressure. Be careful. Too high pressure and bad stuff happens. Are you checking high pressure standby at cylinders, at the diagnostic port, or on the pro 600/700? I would suggest using the diagnostic port to verify pressure before cranking it up to rule out issues with a lift valve.