Flowserve Valtek Valdisk Control Valves - Manual (Page 8)

10-8
Failure Probable Cause Corrective Action
Valve moves to failure 1. Failure of actuator O-ring 1. Replace actuator stem O-ring
position, excessive air 2. Failure of sliding seal assembly 2. Repair or replace sliding seal assembly
bleeding from transfer case
Jerky shaft rotation 1. Overtightened packing 1. Retighten packing box nuts to slightly over
finger-tight
2. Improper adjustment of lever arm on 2. Readjust lever arm (see step 1 in the
shaft causing arm to contact transfer case "Remounting Actuator" section)
3. Cylinder wall not lubricated 3. Lubricate cylinder wall with silicone lubricant
4. Worn piston O-ring allowing piston to 4. Replace O-ring; if galling has occurred
gall on cylinder wall replace all damaged parts
5. Worn actuator stem O-ring causing 5. Replace O-ring; if actuator stem is galled
actuator stem to gall on stem collar replace it
6. Worn (or damaged) shaft bearings, shaft 6. Disassemble and inspect parts; replace
bearings or packing followers any worn or damaged parts
Excessive leakage 1. Improper adjustment of external stroke 1. See "Adjusting External Stroke Stops"
stops section
2. Worn or damaged seat 2. Replace seat
3. Damaged disc seating surface 3. Replace disc and shaft
4. Improper handwheel adjustment acting 4. Adjust handwheel until disc seats properly
as limitstop
Leakage through line 1. Dirty line gasket surfaces 1. Clean gasket surfaces and reinstall valve
2. Improper sealing of line flanges 2. Tighten line flanges evenly and
completely (see Table 1 for proper torque)
3. Flange or pipe misalignment 3. Clean body bore and stem, replace packing
Leakage through 1. Loose packing box nuts 1. Tighten packing box nuts to slightly over
packing box finger-tight
2. Worn or damaged packing 2. Replace packing
3. Dirty or corroded packing 3. Clean body bore and stem, replace packing
Disc interferes with body 1. Disc installed upside down 1. Reinstall disc
2. Worn shaft bearings 2. Replace shaft bearings
Disc interferes with line 1. Cement lining or heavy schedule pipe 1. Modify line to allow proper disc clearance
Valve slams, won't open, or 1. Improper valve installation 1. See step 2 in "Installation" section and
causes severe water hammer correct flow direction
Shaft rotates, disc remains 1. Missing or broken taper pins 1. Replace taper pins
open or closed 2. Broken shaft 2. Replace shaft, make sure shaft is not
overstressing on external stroke stop
Actuator operates, shaft 1. Broken internal actuator parts 1. Refer to appropriate actuator Maintenance
does not rotate Instructions
Troubleshooting Valdisk Valves
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, express or implied, regarding any matter with respect to this product. Because Flowserve is continually improv-
ing 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, contact:
For more information about Flowserve and its products,
contact www.flowserve.com or call USA 972 443 6500
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