Packing Maintenance; Replacing Packing - Fisher EAS easy-e Instruction Manual

ES Valve
July 2017

Packing Maintenance

Key numbers refer to figure 3 for PTFE V‐ring packing and to figure 5 for PTFE/composition packing, unless otherwise
indicated.
For spring‐loaded single PTFE V‐ring packing, the spring (key 8, figure 3) maintains a sealing force on the packing. If
leakage is noted around the packing follower (key 13, figure 3), 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, figure 8)
until the shoulder is against the bonnet. If leakage cannot be stopped in this manner, proceed to the replacing packing
procedure.
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.
1. Isolate the control valve from the line pressure, and release pressure from the valve.
2. Disconnect the operating lines from the actuator and any leak‐off piping from the bonnet. Disconnect the stem
connector, then remove the actuator from the valve by unscrewing the yoke locknut (key 15, figure 8) or the hex
nuts (key 26, figure 8).
WARNING
To avoid personal injury or property damage caused by uncontrolled movement of the bonnet, loosen the bonnet by
following the instructions in the next step. Do not remove a stuck bonnet by pulling on it with equipment that can stretch
or store energy in any other manner. The sudden release of stored energy can cause uncontrolled movement of the bonnet.
If the cage sticks to the bonnet, proceed carefully with bonnet removal.
Note
The following step also helps to provide additional assurance that the valve body fluid pressure has been relieved.
3. Hex nuts (key 5, figure 8) attach the bonnet to the valve. Loosen these nuts or cap screws approximately 3 mm (1/8
inch). Then loosen the body‐to‐bonnet gasketed joint by either rocking the bonnet or prying between the bonnet
and valve body. Work the prying tool around the bonnet until the bonnet loosens.
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Instruction Manual
D100397X012