Control valve problems can severely affect control loop performance and, unless eliminated, they can make controller tuning a challenging (sometimes impossible) task. Some problems are quite obvious to the trained eye and can easily be detected by loop performance assessment software. Others can be more difficult to detect without running specific tests. Make sure to watch out and/or test for valve problems.
Five common problems with control valves are:
– Dead band
– Positioner overshoot
– Incorrect valve sizing
– Nonlinear flow characteristic