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c. Lay the retainer ring on the valve body.
d. Use a press or a soft-faced hammer to press the retainer ring into its groove in the valve body.
CAUTION
It takes a considerable amount of force with a hammer to drive the retainer ring into place. Be sure not to damage retainer
ring surfaces when installing the ring.
e. Theretainerringisproperlyseatedwhenthefaceoftheretainerringisflushwiththefaceofthevalvebody.
f. To ensure proper seal performance for metal seals, you may need to use the hammer to drive the disc open for
the first few times. When closing the valve, use the C clamps discussed in the next few steps.
CAUTION
Do not damage the gasket seating surfaces on either the valve body or the retainer ring when installing or removing the
C-clamps. Protect the gasket surface by using a soft material between the clamp and valve body/retaining ring serrations
to avoid damage.
g. UsethreeC-clampstoholdtheretainerinplace.LocateoneoftheC-clampsnearthetravelstopinthevalve
body, and the other two at 120 degrees from the stop.
h. When cycling the disc for the first three times, use a dead-blow hammer, with a soft head to drive the disc
closed. Also, you may need to use the hammer to drive the disc open for the first few times.
5. For valves with screwed retainer rings
a. Match the retainer ring with the holes in the valve by punching two holes in the gasket to locate where the screw
holes are in the valve.
b. Lay the retainer ring over the gasket, while lining it up with the punched holes. Also insert two retainer screws
(key 17). Finger tighten them.
c. Press the remaining screws through the gasket material and finger tighten them. When all retainer screws are in
place, tighten them in a crisscross pattern.
d. The retainer ring is properly seated when the retainer face is flush with the face of the valve.
6. Turn the disc into and out of the seal ring several times, to help break in the seal and reduce actuator torque
requirements during adjustment.
7. If replacing the packing, remove all packing parts from the valve body. Upon re-assembly of the valve, refer to the
Packing Maintenance procedures to replace the packing.
Seal Ring Maintenance for NPS 2
This procedure is to be performed if the control valve is not shutting off properly (that is, leaking downstream). This
procedure does not require removing the actuator from the valve body. Part key numbers are shown in figure 12.
WARNING
Refer to the WARNING at the beginning of the Maintenance section in this instruction manual.
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