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Installation, Operation and Maintenance Manual
MAN 564_EAC Rev. 2 June 2020
Maintenance
Section 5: Maintenance
Seals replacement
Prior to reassemble check that the actuator components are in good conditions and clean.
Lubricate all the surfaces of the parts, which move in contact with other components, by
recommended oil (SHELL OMALA S4 WE or equivalent). If the O-ring must be replaced,
remove the existing one from its groove, clean the groove carefully and lubricate it
with protective oil lm. Assemble the new O-ring into its groove and lubricate it with a
protective oil lm.
1. Replace the O-rings (39-40) of the head ange (17).
2. Replace the O-ring (42) and the guide sliding ring (41) of the piston (21).
Replace the O-ring (40) of the end ange (22).
If the sealing washer (43) has to be replaced, measure the protrusion of the stop screw
(26) with reference to the end ange (22) surface, so as to be able to easily restore the
setting of the actuator mechanical stop in the closed valve position, once the maintenance
procedures have been completed.
1. Loosen the lock nut (25) and unscrew the stop screw (26) until it is removed
together with the nut (25), the washer (44) and the sealing washer (43).
2. Remove the sealing washer (43) from the stop screw (26). Carefully clean and
lubricate the stop screw thread and the surface of the end ange area, on which
the sealing washer works.
3. Screw the new sealing onto the stop screw until it touches the nut (25).
4. Assemble the washer (44) onto the sealing washer (43).
5. Screw the stop screw into the threaded hole of the end ange until it reaches its
original position (the same protrusion with reference to the ange surface).
6. Check that the sealing washer (43) and the washer (44) are in contact with the
ange surface.
7. Tighten the lock nut (25).
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