11
YT-3400/3450 series
7. Check if feedback lever is parallel to the ground at 50% of the valve stroke. If it is not
parallel, adjust the bracket or feedback link bar to make parallel. Improper installation
may cause poor linearity and may create unnecessary hunting during the operation.
8. Check the valve stroke. The stroke marks are indicated on the feedback lever of the
positioner. Position the connection pin at the number on the feedback lever which
corresponds to the desired valve stroke. To adjust, move the bracket, the connection
pin or both.
Fig. 3:
Pin Insertion when valve stroke is 40mm (up) and is 90mm (bottom)
9. After installing the positioner, operate the valve from 0% to 100% stroke by using direct
air to the actuator (manual position). On both 0% and 100%, the feedback lever should
not touch the lever stopper, which is located on the backside of the positioner. If the
feedback lever touches the stopper, the positioner should be installed further away from
the yoke.
Fig. 4:
Feedback lever should not touch lever stopper 0% ~ 100% valve stroke.
10. After the installation, tighten all of the bolts on the bracket, the feedback lever, and the
connection pin.
