Recommended Maintenance Actions; Disassembly And Reassembly; Disassembly - Flowserve Valtek Valdisk User Instructions

10.4 Recommended Maintenance Actions

1. Look for signs of gasket leakage through body and line
gaskets. Tighten flange bolting if necessary.
2. Check for corrosion and damages on the valve.
3. Clean valve and paint any areas of severe oxidation.
Do not overtighten packing. Sudden
exposure of the control valve to full
working pressure and temperature may cause stress
cracks.
4. Check packing box bolting for proper tightness. Tighten as
necessary to prevent stem leakage.
5. If valve is supplied with a lubricator, check lubricant supply,
and add lubricant if necessary.
6. If possible, stroke the valve and check for smooth, full-
stroke operation by observing the disk position indicator
plate mounted on the transfer case or the gland flange.
Unsteady movement of the disk could indicate an internal
valve problem (stick-slip breakout motion is normal
whenever graphite packing is used).
7. Check positioner calibration by observing the gauges and
the disk position. Make sure the positioner is calibrated to
the correct range.
8. Remove transfer case cover plate and make sure the
positioner linkage and internal actuator parts are securely
fastened. Also, check for air leaks through actuator stem
seal, using a soap solution.
Never apply air to the actuator without
the cover plate installed; otherwise, the
unsupported shaft may sustain damage.
9. Be sure that all the accessories like positioner, limit switch,
solenoids and Air filter regulators are securely fastened.
10. If possible, remove air supply and observe stroke indication
for correct fail-safe action.
11. Spray soap solution around the cylinder retaining ring and
the adjusting screw to check for air leaks through the O-
rings.
12. Clean any dirt or other foreign material from the exposed
portion of the shaft.
13. If an air filter is supplied, check cartridge, and replace if
necessary and ensure correct vertical orientation.
VAIOM000286-02 (EN/AQ) May 2023
Valtek Valdisk High-Performance Butterfly Control Valves

11 Disassembly and Reassembly

The Valtek Valdisk control valve is allowed to be
disassembled and reassembled only by qualified staff -
personnel who are familiar with disassembling,
reassembling, installation and commissioning of this
product, and possess the relevant qualifications in their
field of activity.
When performing repairs, personnel are to follow these
instructions using only original equipment manufacturer (OEM)
spare parts and recommended special tools to ensure the
reliability of the Valtek Valdisk control valve.
Only Flowserve trained and authorized personnel are allowed to
repair (disassemble and reassemble) the Valtek Valdisk in
hazard areas.
Valves are provided for oil and grease-less service, or oxygen
service ay only disassembled and reassembled in clean rooms
(ISO 14644- ISO-8, US FED STD 209 E - M 6.5, or equivalent).

11.1 Disassembly

If an internal problem is suspected with the valve and
disassembly is required, remove the valve from the line by
proceeding as follows:
To carry out this operation, it is
essential to disconnect the valve from
the pipework. Depressurize line to atmospheric pressure
and drain all fluids before working on the valve. Failure to
do so can cause serious injury.
1. Make sure valve (disk) is fully closed.
On valves with fail-open action, air pressure
must be supplied under the actuator piston to
close the valve. If the valve is supplied with a handwheel, it can
be used to close the valve.
2. Attach a hoist or some means to support the valve. If lifting
holes are provided in the body, properly installed
shouldered eye bolts or hoist rings to be used along with a
strap around the actuator to balance the entire valve weight
safely.
3. Remove the line bolting. Do not attempt to pry line flanges
apart by pushing or pulling on valve actuator.
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