A control valve which should go to closed position on control signal failure should be labeled
- FC - Fail-Closed
The control signal may be pneumatic, hydraulic or electric.
Control Valve terminology, bodies, trim, flow characteristics, Cv and Kv sizing, noise, actuators and positioners
A control valve that should stay put if control signal or air fails.
A control valve that goes to open position if control signal or air fails.
Valves and the term Normally Closed.
Valves and the term Normally Open.