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Instruction Manual
D102175X012
Packing Maintenance
This section covers PTFE V‐ring, double PTFE, and graphite packing used in extension bonnets (figures 2, 3, and 4).
Note
If the valve has ENVIRO‐SEAL live‐loaded packing installed, refer to the instruction manual ENVIRO‐SEAL Packing System for Sliding
Stem Valves for packing instructions. Figure 6 shows typical ENVIRO‐SEAL arrangements.
Standard packing key numbers are shown in figures 2, 3, and 4. ENVIRO‐SEAL packing key numbers are shown in
figure 6. Bonnet key number locations are shown in figure 7, and valve key numbers are shown in figures 8 and 9.
For spring‐loaded single PTFE V‐ring packing, the spring (key 8) maintains a sealing force on the packing. If leakage is
noted around the packing follower (key 13), check to be sure the shoulder on the packing follower is touching the
bonnet. If the shoulder is not touching the bonnet, tighten the packing flange nuts (key 5), until the shoulder is against
the bonnet. If leakage cannot be stopped in this manner, proceed with replacing packing procedures.
If there is undesirable packing leakage with other than spring‐loaded packing, first try to limit the leakage and
establish a stem seal by tightening the packing flange nuts.
If the packing is relatively new and tight on the stem, and if tightening the packing flange nuts does not stop the
leakage, it is possible that the valve stem is worn or nicked so that a seal cannot be made. The surface finish of a new
valve stem is critical for making a good packing seal. If the leakage comes from the outside diameter of the packing, it
is possible that the leakage is caused by nicks or scratches around the packing box wall. If performing any of the
following procedures, inspect the valve stem and packing box wall for nicks and scratches.
Replacing Packing
WARNING
Refer to the WARNING at the beginning of the Maintenance section in this instruction manual.
Key numbers and sequence of assembly of packing parts are shown in figures 2, 3, and 4. Bonnet key number locations
are shown in figure 7, and valve key number locations are shown in figures 8 and 9, unless otherwise noted.
1. Isolate the control valve from the line pressure, release pressure from both sides of the valve body, and drain the
process media from both sides of the valve. If using a power actuator, also shut off all pressure lines to the power
actuator, and release all pressure from the actuator. Use lock‐out procedures to be sure that the above measures
stay in effect while you work on the equipment. Observe the Warnings at the start of the Maintenance section.
2. Disconnect the operating lines from the actuator and any leak‐off piping from the bonnet. Disconnect the stem
connector and remove the actuator from the valve by unscrewing the yoke locknut (key 15) or hex nuts (key 26, not
shown).
3. Loosen the packing flange nuts (key 5) so that the packing is not tight on the valve stem. Remove any travel
indicator parts and stem locknuts from the valve stem threads.
WARNING
D To avoid personal injury or property damage caused by uncontrolled movement of the bonnet, loosen the bonnet by
following the instructions in the next steps.
EZ-C, ET-C, and EWT-C Valves
July 2017
7
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