Instruction Manual
D100425X012
YD and YS Valves
July 2017
6
Packing Maintenance
Note
For valves with ENVIRO‐SEAL packing, see the Fisher instruction manual ENVIRO‐SEAL Packing System for Sliding‐Stem Valves for
packing instructions.
For valves with HIGH‐SEAL packing, see the Fisher instruction manual HIGH‐SEAL Live‐Loaded Packing System for packing
instructions.
Packing Replacement
WARNING
Observe the warning at the start of the Maintenance section.
Table 3. Recommended Torque for Packing Flange Nuts
VALVE STEM
DIAMETER
PRESSURE
RATING
GRAPHITE TYPE PACKING
PTFE TYPE PACKING
Minimum Torque
Maximum Torque
Minimum Torque
Maximum Torque
mm
Inches
N
S
m
Lbf
S
in
N
S
m
Lbf
S
in
N
S
m
Lbf
S
in
N
S
m
Lbf
S
in
9.5
3/8
CL125,
150
3
27
5
40
1
13
2
19
CL250,
300
4
36
6
53
2
17
3
26
CL600
6
49
8
73
3
23
4
35
12.7
1/2
CL125,
150
5
44
8
66
2
21
4
31
CL250,
300
7
59
10
88
3
28
5
42
CL600
9
81
14
122
4
39
7
58
19.1
3/4
CL125,
150
11
99
17
149
5
47
8
70
CL250,
300
15
133
23
199
7
64
11
95
CL600
21
182
31
274
10
87
15
131
25.4
1
CL300
26
226
38
339
12
108
18
162
CL600
35
310
53
466
17
149
25
223
31.8
1‐1/4
CL300
36
318
54
477
17
152
26
228
CL600
49
437
74
655
24
209
36
314
The following procedure covers PTFE V‐ring packing. A similar procedure can be followed for PTFE/composition
packing. However, because PTFE/composition packing comes in split rings, it is possible to replace the rings without
removing the actuator from the valve.
Installation of graphite ribbon/filament packing requires special care to avoid trapping air between the rings. Start only
one ring at a time without forcing the top of the packing ring below the bottom of the entrance chamfer of the
packing box. Thus, when a ring is added, the stack should not be pushed into the cavity more than the thickness of the
added ring.
The arrangement of packing box parts is shown in figures 3, 4, 5, 6, and 7. Key numbers used in the following steps are
shown in figures 13 and 14.
