Instruction Manual
D101299X012
RSS Valve
July 2017
8
Packing Maintenance
Key numbers are shown in figure 10.
The packing consists of braided packing rings (key 13). The packing box is only a safety measure in case of a leak
through the bellows (key 6). Therefore, the packing follower (key 11) is tightened to 1.13 N
S
m (10 lbf
S
in) of torque
and then loosened one half turn. To detect a leak through the bellows (key 6), the bonnet (key 2) can be provided with
a connection for leak‐off piping.
Replacing Packing and Bushing Inserts
Key numbers are shown in figure 10.
1. Isolate the control valve from the line pressure. Release pressure from both sides of the valve and drain the process
media from both sides of the valve.
2. Exhaust all actuator pressure, and disconnect the operating lines from the actuator and any leak‐off piping from the
bonnet (key 2). Disconnect the actuator stem connector, and then remove the actuator from the valve by
unscrewing the yoke locknut (key 14).
3. Remove any travel indicator parts, the locknut (key 10), and the travel stop (key 16) from the valve stem (key 5)
threads.
CAUTION
Follow the procedures as described in the next steps to prevent damage to the bonnet sealing surface and to prevent
packing box leakage.
4. Remove the packing follower (key 11). Unscrew the cap screws (key 7) and hex nuts (key 8) that secure the bonnet
(key 2) to the valve (key 1). Then, carefully lift the bonnet off and set it on a protective surface to prevent damage to
the bonnet sealing surface. If the valve stem, bellows, and valve plug (keys 5, 6, and 3) come out with the bonnet,
remove these parts from the bonnet.
5. Remove bushing inserts, packing rings, and packing box ring (keys 13, 12, 28, and 29).
6. Clean the packing box, packing box ring, and packing follower.
7. Inspect the valve stem and packing box surfaces for any sharp edges that might cut the packing. Scratches or burrs
could damage new packing or cause packing box leakage. If the surface condition cannot be improved by light
sanding, replace the damaged parts.
8. Install bushing inserts (keys 28 and 29).
9. Install the bonnet (key 2) over the valve stem (key 5). Slide the bonnet down until it properly engages the bonnet
locating diameter (figure 5) of the valve.
Note
In order to ensure accurate positioning of the valve plug (key 3) and seat ring (key 4), clearance between the valve and bonnet at
all bolting locations (figure 5) must be equal and approximately 2.0 mm (0.080 inches) for NPS 1 through 4 valves. Be sure to
measure the clearance in the next step.
10. Tighten the cap screws and hex nuts (keys 7 and 8) in a crisscross pattern to a maximum torque value of 50 N
S
m
(37 lbf
S
ft). To ensure accurate positioning of the valve plug (key 3) into the seat ring (key 4), check the gap between