Flowserve G4 Marathon Sleeveline Plug Valves - Manual (Page 3)

SECTION II
OPERATING/MAINTENANCE INSTRUCTIONS FOR
G4 MARATHON, G4Z MARATHON, G4R MARATHON
Maintenance requirements for G4 Marathon, G4Z Marathon
and G4R Marathon valves may vary due to operating condi-
tions of the process. Factors such as operating temperature,
pressure, solids content, and frequency of cycling can influ-
ence valve performance and maintenance requirements.
Seal wear is compensated by adjusting appropriate parts. For
G4 Marathon, G4Z Marathon and G4R Marathon valves, there
are three possible leak paths:
1. Top Cap (bonnet)
2. Stem
3. Line (through)
Corresponding adjustments for each leak path are as follows:
Note: Refer to Figure II-1 or Figure VI-1A for parts identification.
1. Top Cap (bonnet)
Leakage due to thermal or pressure cycling is eliminated
by snugging the top cap fasteners (Part 3A) in a “criss-
cross” pattern. This adjustment is most effective when the
valve is not pressurized. It is important that the top cap
fasteners not be tightened excessively and that torque
values applied be within industry standard for fasteners.
2. Stem
Leakage due to wear of the diaphragm, and/or wear to
the sleeve (primary seal) is eliminated by tightening the
adjuster fasteners (Part 12A) in
1 / 4 turn increments. It is
recommended that the adjuster fasteners be tightened
evenly.
The valve should be operated between adjustments to
assure that the plug properly seats itself into the sleeve.
If leakage persists after repeated adjustments, the sleeve
and diaphragm will require replacement as covered in
Section V A and V B or Section VI.
3. Line (through)
Through leakage due to wear of the primary seal can be
eliminated by tightening the adjuster fasteners (Part 12A)
in
1 / 4 turn increments. It is recommended that the
fasteners be tightened evenly.
The valve should be operated during adjustments to pre-
vent excessive operating torque. Should leakage persist
after repeated adjustments, the sleeve will require replace-
ment as covered in Section V A and V B or Section VI.
3
▲WARNING
To avoid personal injury and prevent damage to equip-
ment, do not operate or repair this valve without observ-
ing the following procedures outlined in this manual.
!
Flow Control Division
Section 1.0
WRENCH (13)
STOP COLLAR RETAINER (19A)
STOP COLLAR (19)
ADJUSTER FASTENERS (12A)
ADJUSTER (12)
TOP CAP FASTENERS (3A)
TOP CAP (3)
GROUNDING SPRING (17)
THRUST COLLAR (11)
TEFLON BACK-UP RINGS (20) &
O-RINGS (21)
DIAPHRAGM (6)
PLUG (2)
SLEEVE (5)
BODY (1)
FIGURE II-1
TYPICAL ASSEMBLY OF G4 MARATHON AND
G4R MARATHON VALVE