ENGINEERED & PROCESS VALVES
16
02/2011 / IOM-WKM-GATE-PRS-01
Installation, Operation and Maintenance Manual
Trouble Probable Cause Remedy
The stem seal is leaking due to a contaminated
stem.
Cycle the valve serveral times.
Leakage is occurring around the stem, yoke tube
drain, or yoke tube to bonnet joint
The stem seal is leaking due to dammage or
abnormal wear.
ALL VALVES EXCEPT THOSE WITH OUTSIDE
PACKING GLANDS (OPG/OS&Y)
Inject plastic packing as follows:
Remove the packing fitting screw and install a
packing injection gun
1
loaded with the proper
plastic injectable. Refer to the
“Recommeded Lubricants and Sealants” (chart).
Using the packing gun, pump plastic to energize
the packing set. 4000-5000 psig (275-345 barg) is
usually sufficient. DO NOT EXCEED10,000 psig (690
barg)
TROUBLESHOOTING
Leakage is occurring around the stem, yoke tube
drain, or yoke tube to bonnet joint.
The stem seal is leaking due to damage or abnor-
mal wear.
WARNING: THE INJECTION PRESSURE IS
TWICE THE HYDRAULIC GAUGE PRESSURE.
Hold for at least 3 minutes. Re-pressurize, as
needed.
Remove the packing gun.
Lubricate the packing fitting screw thread with a
good grade of bearing grease. Thread it into the
fitting.Tighten securely but do not exceed 7 ft-lbf
of torque.
(9.5 N-M).
VALVES WITH OUTSIDE PACKING
GLANDS (OPG)
Tighten the gland bolts in a alternating crossing
pattern to stop the leak. Do not over tighten.
The Grease fitting or bleed plug is leaking. The safety cap or bleed plug screw is loose. Tighten the safety cap or bleed plug screw.
The valve is leaking around bonnet to
body joint.
The bonnet seal is leaking. Insure that the bonnet nuts are tightened prop-
erly. Call CAMERON VALVES &
MEASUREMENT representative if
leakage persists.
A restriction is present in the valve bore. The gate is not properly aligned with the seats. HANDWHEEL OR BEVEL GEAR OPERATED
VALVES: Open the valve fully by turning the
handwheel counter-clockwise.
Tighten securely.
DO NOT BACK OFF THE HANDWHEEL.
MOTOR OPERATED VALVES: Make sure the
operator limit switches are set correctly.
The valve will not open
or close.
The valve is pressure locked
2
. Vent the body pressure by using a pressure
releasing tool on one of the body vent fittings.
The valve is hard to
operate.
The lubrication is not sufficient. Lubricate the bearings, operator, and/or seats
per the Routine Maintenance Section. Lubricate
the operator per the manufacturer’s instructions.
Ice is present in the yoke tube, handwheel unit, or
operator.
Apply heat to melt ice.
Line bind is present. (Pipeline bending
moments distorting the valve body).
Relieve the bind or moment on the valve.
(continued next page)
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