Troubleshooting - Flowserve Valtek Mark Six Installation, Operation & Maintenance Instructions Manual

9/17/03
TROUBLESHOOTING MARK SIX VALVES

Troubleshooting

Failure
Stem motion 1. Overtightened packing
impeded 2. Service temperature is beyond operating limits
of trim design
3. Inadequate air supply
4. Stem frozen at upper packing
5. Malfunctioning positioner
Excessive leakage 1. Improperly tightened bonnet flange bolting
2. Worn or damaged seat ring
3. Worn or damaged seat or bonnet gasket
4. Inadequate actuator thrust
5. Incorrectly adjusted plug
6. Improper flow direction
7. Improper handwheel adjustment acting as a
limit-stop
Inadequate flow 1. Improper plug adjustment, limiting stroke
2. Malfunctioning positioner
3. Service conditions exceed trim design capacity
Plug slams 1. Incorrect plug adjustment allowing improper
cushion of air between actuator piston and yoke
2. Inadequate air supply
3. Trim sized too large for flow rate
Valve does not 1. Incorrect flow direction
fail in correct
position
Flowserve Corporation has established industry leadership in the design and manufacture of its products. When properly selected, this Flowserve product is
designed to perform its intended function safely during its useful life. However, the purchaser or user of Flowserve products should be aware that Flowserve
products might be used in numerous applications under a wide variety of industrial service conditions. Although Flowserve can (and often does) provide general
guidelines, it cannot provide specific data and warnings for all possible applications. The purchaser/user must therefore assume the ultimate responsibility for
the proper sizing and selection, installation, operation and maintenance of Flowserve products. The purchaser/user should read and understand the Installation,
Operation, Maintenance (IOM) instructions included with the product, and train its employees and contractors in the safe use of Flowserve products in connection
with the specific application.
While the information and specifications presented in this literature are believed to be accurate, they are supplied for informative purposes only and should not be
considered certified or as a guarantee of satisfactory results by reliance thereon. Nothing contained herein is to be construed as a warranty or guarantee, expressed
or implied, regarding any matter with respect to this product. Because Flowserve is continually improving and upgrading its product design, the specifications,
dimensions and information contained herein are subject to change without notice. Should any question arise concerning these provisions, the purchaser/user
should contact Flowserve Corporation at any of its worldwide operations or offices.
For more information about Flowserve and its products, contact www.flowserve.com or call USA 801 489 8611.
For more information, contact:
VLENIM0006-03 (AQ) July 2019
Flowserve is a registered trademark of Flowserve Corporation.
3:22 PM Page 2
Probable Cause Corrective Action
1. Adjust packing box nuts to slightly over finger-tight.
2. Reconfirm service conditions and contact factory.
3. Check for leaks in air supply or instrument signal system; tighten
loose connections and replace leaky lines.
4. Temperature around packing should be increased or a longer
extension may be required.
5. Refer to positioner maintenance instructions.
1. Refer to step 3 of "Reassembling the Body" section for correct
tighening procedure.
2. Disassemble valve and replace or repair seat ring.
3. Disassemble and replace gaskets.
4. Check for adequate air supply to actuator; if air supply is
adequate, reconfirm service conditions and contact factory.
5. Refer to steps 8–10 of "Reassembling the Body" section for
correct plug adjustment.
6. Refer to original specifications or contact factory.
7. Adjust handwheel until plug seats properly.
1. Refer to steps 8–10 of "Reassembling the Body" section for correct
plug adjustment.
2. Refer to positioner maintenance instructions.
3. Verify service conditions and consult factory.
1. Refer to steps 8–10 of "Reassembling the Body" section for correct
plug adjustment.
2. Check air supply to actuator; repair leaks and remove any
restrictions in supply line.
3. Install reduced trim.
1. Reconfirm direction and, if necessary, correct flow direction
through valve.
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