A Critical Warning message in AFT Impulse.

Full message is:

FCV/PRV/PSV could not control pressure/flow at Junction X. Pressure was added to achieve control flow. See Valve Summary for more information.

A flow or pressure control valve could not control pressure/flow and the setting is to Always Control (Never Fail). In order to achieve the control flow or pressure, the valve must add pressure and act like a pump.

This warning is useful for resolving operational problems in your system.