Flowserve G4 Marathon Sleeveline Plug Valves - Manual (Page 4)

Recommended Precautionary Measures
1. Valves must be relieved of process fluid and pressure
prior to disassembly.
2. Personnel performing disassembly must be suitably
protected and alert for emission of hazardous process
fluid.
3. If there is a pipe plug located at the bottom bowl of
the valve, DO NOT remove the pipe plug until the valve
plug has been removed.
Disassembly Steps
NOTE: Refer to Figure II-1 or VI-1A for parts identification. If
an actuator or gearbox operates the valve, alignment marks
should be noted to assure correct orientation when reassem-
bled. This may best be accomplished by making matching
marks on the plug stem and operator housing with no burrs
on the plug stem.
1. Gradually loosen adjuster fasteners (Part 12A) – DO
NOT REMOVE.
2. Turn plug (Part 2) in order to raise the plug to vent any
material trapped in the valve (see note below).
Note: If there is no upward movement of the plug
(Part 2), it will be necessary to devise a method of lifting
the plug upward. This may require removal of the valve
operator (Step 3). This operation should be undertaken
noting the above precautionary measures. Methods of
plug removal must include protective measures on plug
stem and plug end.
3. WARNING: Do not loosen or remove top cap fasteners
(Part 3A) when removing an operator or accessory.
Remove the operator by unfastening it from the
bracket.
4. Once the plug (Part 2) has lifted, the adjuster fasteners
(Part 12A) can be completely removed.
5. Gradually loosen but DO NOT REMOVE all of the top cap
fasteners (Part 3A). Turn the plug until it is loose from
the sleeve (Part 5) and all pressure has been vented.
(Again, it may be necessary to use a mechanical means
to move the plug upwards.)
6. Remove the top cap fasteners (Part 3A) and top cap
(Part 3) from the plug stem (Part 2).
7. Remove the plug (Part 2) from the body (Part 1).
8. Remove the grounding spring (Part 17) and thrust collar
(Part 11) from plug stem (Part 2).
9. Remove the o-rings (Part 21), backup rings (Part 20) and
the diaphragm (Part 6) from the plug stem (Part 2).
10. Inspect the valve sleeve (Part 5) for wear or damage,
especially scratches near the top, bottom, and port areas.
If wear or damage is excessive, the sleeve should be
replaced.
11. Remove sleeve (Part 5) as follows:
NOTE: Care should be taken not to damage the internal
body bore.
a. Using a screw driver and mallet, cut the old sleeve
through one of the port openings, top and bottom.
b. Grasp the sleeve with a pair of pliers while twisting,
and lift the sleeve from the body.
12. Thoroughly clean all valve parts with an acceptable
cleaner.
13. Inspect parts for damage. Look for marred, scratched, or
rough sealing surfaces on the valve plug (Part 2).
NOTE: Reinstallation of damaged or unclean parts will
ruin any replacement seals installed into the valve.
SECTION III
VALVE DISASSEMBLY – G4 MARATHON, G4Z MARATHON, G4R MARATHON
4
Flow Control Division
Section 1.0