Electro-Pneumatic Positioner
When installing a positioner, please ensure to read and follow safety instructions.
Any input or supply pressures to valve, actuator, and / or to other related devices must
be turned off.
Use bypass valve or other supportive equipment to avoid entire system “shut down”.
Ensure there is no remaining pressure in the actuator.
Installation Steps
1. Proper bracket must be made in order to adapt the positioner on the actuator yoke.
Please consider following important points when a bracket is being designed.
Positioner’s feedback lever must be parallel to the ground at 50% of the valve stroke.
Feedback lever connection with the pin of the actuator clamp should be installed in such a way that the valve stroke length coincides with the corresponding figure in “mm” marked on the feedback lever. Improper setting may cause poor linearity and
may create unnecessary hunting during the operation.
2. Assemble the positioner with the bracket made in
previous step by fastening the bolts. Please refer to the
backside of the positioner for size of the bolts. The
standard bolt size is M8 x 1.25P. Please contact Young
Tech Co., Ltd for other bolt sizes.
3. Attach the positioner with bracket to the actuator yoke – DO NOT
TIGHTEN POSITIONER COMPLETELY.
4. Connect positioner’s feedback lever to the actuator clamp. The
hole gap on the feedback lever is 6.5mm. The connection pin’s
outer diameter should be less than 6.3mm.
5. Connect supply pressure to the actuator temporarily. Supply enough supply pressure to the actuator in order to position the actuator clamp at 50% of the total valve stroke.
6. Insert connection pin into the feedback lever. The pin should be inserted when the actuator clamp is at 50% of the total valve stroke.
Proper way to connect feedback lever, connection pin, and lever spring
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
10. After the installation, tighten all of the bolts on the bracket, the feedback lever, and the connection pin.
