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9500 Valve
February 2019
Table 4. Troubleshooting Guide
Fault
1. Leakage out sides of
a. Hub seals require adjustment.
valve (at thrust plates)
between thrust bushings
b. Taper pins are not sealed.
and shaft.
2. Leakage out sides of
a. Flange gaskets used.
valve (at thrust plates)
between valve body and
b. Partial O‐ring bead on liner faces damaged.
thrust bushings, leakage at
flanges, faces, or both
3. Leakage through
a. Hub seals require adjustment.
disk/liner seal
b. Linkage requires adjustment.
c. Actuator has insufficient torque output to close disk
against pressure drop. (Actuators are selected to have
sufficient torque output to shut off the flow against a specific
pressure drop, not necessarily against the maximum
allowable pressure drop. Be sure that the pressure drop for
which the actuator is selected is not being exceeded.)
d. Liner has been damaged by flowing medium or other valve
parts damaged by being subjected to service conditions
beyond those for which valve is designed.
4. Valve shaft will not
a. If actuator does not stall, but shaft does not rotate, the
rotate
spline teeth on the valve shaft are sheared.
b. If actuator stalls, shaft is binding in bushings due to
linkage misalignment caused by excessive wear of linkage
parts.
c. If actuator stalls and linkage is not misaligned, actuator
may have insufficient output torque to rotate disk against
flow.
5. Valve shaft rotates, but
Taper pins (or drive shaft spline for coated‐disk
valve does not control
constructions) have been sheared due to obstruction to disk
process fluid
rotation or other internal parts damaged by being subjected
to service conditions beyond those for which the valve was
designed.
2. If necessary, pry flanges apart so that liner faces will not be damaged when the valve is being removed. Inspect the
disk (key 3) and liner (key 2) for wear or damage.
3. Remove the actuator from the valve. Follow instructions in the appropriate actuator instruction manual.
4. From both sides of valve, unscrew thrust‐plate cap screws (key 10) and remove thrust plates (key 9).
5. If taper pin (key 15) ends are peened, grind off the peened portions. Driving from the smaller end of the pins, drive
the pins out of the disk (key 3) and shaft (key 4).
WARNING
Once the shaft has been removed, the disk may fall from the valve body, causing personal injury or disk damage. Support
the disk before removing the shaft.
6. Pull the shaft out of the valve body. If the shaft cannot be pulled from the valve body, drive the shaft out but use
care to avoid upsetting the end of the shaft.
7. Remove the disk from the valve body.
10
Possible Cause
Instruction Manual
Correction
a. Adjust using Hub Seals portion of Adjustments
procedures.
b. Remove valve from line and re‐seat taper pins or install
new taper pins using Maintenance procedures.
a. Check to see if flange gaskets are being used; if so, remove
gaskets.
b. Replace liner using Maintenance procedures.
a. Adjust seals using Hub Seals portion of Adjustments
procedures.
b. Refer to Linkage portion of Adjustments procedures.
c. If possible, check shutoff at lower pressure drops. If shutoff
is obtained at low pressure drops, but actuator stalls and
does not produce full disk rotation at service pressure drop,
actuator output torque is too low. For piston actuators, it
may be possible to increase output torque by increasing
supply pressure. Do not exceed maximum allowable supply
pressure of actuator.
d. Inspect and replace parts using Maintenance procedures.
a. Refer to the actuator instruction manual to remove
actuator cover plate. Replace valve shaft using Maintenance
procedures if spline teeth are sheared.
b. Replace linkage parts.
c. Check actuator operation with no pressure applied to the
valve. If valve now functions properly, actuator is too small.
Inspect and replace parts using the Maintenance procedures.
D100380X012
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