without a positionar can a control valve operate? give the
difference of operating with positionar and without positionar?

Answer Posted / kkrameshkumar

Only the diaphragm actuator type control valves can be
operated without positioners provided that the spring range
of the actuator is within the range of control air pressure.

Cylinder actuator type control valves cannot be operated
proportionally without a positioner. only on/off can be
done.

With positioner we can achive the exact position of the
control valve with speed. If positioner is not there then
the actuation will be sluggish and we cannot get exact
postioning of control valve

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