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8540 Valve
September 2021
Key numbers are shown in figure 12 unless otherwise noted.
Disassembly
Most maintenance procedures will require the actuator to be removed.
1. Isolate the control valve from line pressure, and relieve pressure from the valve body. Shut off and disconnect all
lines from the power actuator.
2. Be sure the disk is in the closed position before attempting to remove the valve from the pipeline or flanges
D For Fail‐Open Actuators: It will be necessary to provide a temporary loading pressure to the actuator diaphragm to
move the valve disk to the closed position. Observe the above Warning when closing the valve. If a loading pressure
is required, use caution when working with the valve. If the loading pressure is disconnected, the disk will open
rapidly.
3. With the disk in the closed position, remove line bolting, then remove the control valve assembly from the pipeline.
R emove the actuator as described in the Packing Maintenance section.
4.
5. Remove the retainer ring (key 2, figure 8):
D Place the valve on blocks with the seal retainer facing down. (Note: Position blocks so they do not restrict the
retainer ring removal.)
D Rotate the disk to the open position as shown in figure 7.
D Locate one of the knock‐out points machined on the retainer ring. Using a hammer and flat end punch the
knock‐out point, pop out the retainer ring from the valve body.
CAUTION
When popping out the retainer ring, be very careful to hit only the knock‐out points. Hitting anywhere else can cause
non‐repairable damage to the t‐slot area.
D Clean all sealing surfaces and parts before re‐assembly.
6. Remove the seal ring from the valve body seal ring slot. Remove the spring from the PTFE seal ring (key 5) as it may
be necessary to re‐install the spring into the new PTFE seal ring.
7. If it is necessary to replace the disk, drive shaft, and the bearings, refer to that section below before proceeding with
the assembly procedures for the seal ring and retainer. The seal ring could be damaged if it is in place while
removing the disk.
Assembly
Place the valve on blocks with the seal retainer facing up. If the replacement disk, shaft, and bearings have not been
installed in the valve body, go to the proper assembly procedures to install them.
CAUTION
Do not install the seal ring without the disk being in place. The seal ring could be damaged while installing the disk.
12
Instruction Manual
D104709X012
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