A Critical Warning message in AFT Fathom

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 or flow and the setting in the Control Valve Properties window is to Always Control (Never Fail). In order to achieve the control flow or pressure, the valve must add pressure at the junction.

The Valve Summary in the Output window gives more information.

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