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Instruction Manual
D104191X012
seal ring, upper anti-extrusion ring, and back up ring (key 63, 24, 25, and 33) into the plug, as shown in figure 7,
view B. Then install the retaining ring (key 26) by inserting one end in the groove and pressing the ring into the
groove while turning the plug. Again, be careful not to scratch any surfaces of the ring or plug.
NPS 4 design for application up to and including 316_C (600_F) (figure 8): Using a punch, drive the pin (key 5)
further into the pin hole, as shown in figure 9. To prevent damaging the outer diamter of the plug, use a face
spanner wrench to unthread the seal retainer (key 4) from the plug (key 2) using the pin holes on the top surface of
the seal retainer, as shown in figure 9. Once the seal retainer is unthreaded, slide the upper anti-extrusion ring, seal
ring, bi-directional back up ring, seal ring, and anti-extrusion ring (key 63, 24, and 33) off the plug.
Inspect all parts for defects and cleanliness and replace the damaged parts. The removed seal set soft parts should
not be reused. To install the new seal parts, slide the lower anti-extrusion ring, seal ring, bi-directional back up ring,
seal ring, and upper anti-extrusion ring (key 63, 24, and 33) into the plug, as shown in figure 8, view B. Then, apply
anti-seize lubricant (key 45) to the seal retainer threads and flat mating surfaces between the seal retainer and plug
(key 2 and 4). Install the seal retainer into the plug (key 2 and 4) and tighten it with a spanner wrench until the pin
holes are aligned. Retain the seal retainer (key 4) to the plug (key 2) by pinning a new pin (key 5) into one of the
remaining pin holes with 0.025" depth from the surface. Do not insert the pin into a pin hole that was previously
pinned, as shown in figure 9.
NPS 2 and 3 unbalanced design for application above 316_C (600°F) (figure 12 and 13): No seal is required for the
unbalanced design. Inspect all parts for defects and cleanliness and replace the damaged parts.
NPS 4 Balanced Bore-seal Valve Plug Maintenance
Except where indicated, NPS 4 Balanced Bore-seal Valve Plug key numbers are referenced in figure 14. Contact your
Emerson sales office for Bore Seal trim replacement.
Note
Due to the design requirement of this product, the valve and stem are precision-matched and the stem is not replaceable. If
damaged, the valve plug and stem must be replaced as an assembly. The set of valve plug and stem assembly, seat ring retainer
and Bore-seal is designed as a whole assembly trim set, which might need special tool and fixture to remove and install. Contact
your
Emerson sales office
for parts replacement.
CAUTION
To avoid leakage when the valve is returned to service, use appropriate methods and materials to protect all sealing
surfaces of the trim parts during maintenance. Use caution when removing piston ring(s) and the Bore Seal plug seal to
avoid scratching any sealing surface.
Do not remove the valve stem from the plug/retainer assembly unless you are planning to replace the valve stem. Never
reuse an old valve stem with a new plug or reinstall a valve stem after it has been removed. Replacing a valve stem requires
drilling a new pin hole in the stem. This drilling weakens the stem and may cause failure in service.
Follow instructions carefully to avoid damaging the product surfaces, which could result in damage to the product. Protect
all surfaces of the valve plug, valve seat ring, and seat ring retainer during maintenance to ensure control valve accuracy
and choking performance is not affected.
1. With the whole valve plug and stem assembly, seat ring retainer and Bore-seal set (key 2, 4, 7, 8, 17 ) removed from
valve body (key 1), pull the valve stem (key 7) to the top end of seat ring retainer (key 3) as shown in figure 15.
Remove the two graphite piston rings (key18, figure 14). To remove plug retainer for maintenance purpose, locate
the staked thread on top of the valve plug (key 2) between the valve plug and plug retainer. The staked thread
secures the retainer. Use a drill with a 1/8 inch bit to drill out the staked area of the thread. Drill approximately 1/8
CCV-N Valve
October 2018
11
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