Flowserve Valtek Mark 14 - Manual (Page 7)


Valtek Mark 14 Control Valves FCD VLENIM0115-00 – 06/06
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4 Quick-check
Prior to start-up, check the control valve by following these steps:
4.1 Stroke the valve and observe the plug position indicator on the stem clamp compared to the
stroke indicator plate. The plug should change position in a smooth, linear fashion.
NOTE: Due to excessive friction, graphite packing can cause the plug stem to move in a jerky fashion.
4.2 Check for full stroke by making appropriate instrument signal changes.
4.3 Check all air connections for leaks.
4.4 Check packing box bolting for the correct adjustment. Refer to the packing installation manual
for specific details on maintaining the style of packing supplied.
CAUTION: Do not overtighten packing. This can cause excessive packing wear and high stem
friction that may impede plug movement.
4.5 Make sure the valve fails in the correct direction in case of air failure. This is done by turning
off the air supply and observing the failure direction.
4.6 After a temperature excursion has occurred, bonnet flange bolting should be re-torqued to
ensure bonnet seals do not leak.
5 Valve Maintenance
At least once every six months, check for proper operation by following the preventative mainte-
nance steps outlined below. These steps can be performed while the valve is in-line and, in some
cases, without interrupting service. If an internal problem is suspected, refer to Section 6, Valve
Disassembly and Inspection.
5.1 Look for signs of gasket leakage through the end flanges and bonnet. Re-torque flange and
bonnet bolting (if required).
5.2 Examine the valve for damage caused by corrosive fumes or process drippings.
5.3 Clean valve and repaint areas of severe oxidation.
5.4 Check packing box bolting for proper tightness. Refer to the packing installation manual for
specific details on maintaining the style of packing supplied.
CAUTION: Do not overtighten packing. This can cause excessive packing wear and high stem
friction that may impede stem movement.
5.5 If possible, stroke the valve and check for smooth, full-stroke operation. Unsteady stem move-
ment could indicate an internal valve problem.
NOTE: Due to excessive friction, graphite packing can cause the plug stem to move in a jerky fashion.
WARNING: Keep hands, hair and clothing away from all moving parts when operating the valve.
Failure to do so can cause serious injury.
5.6 Make sure positioner linkage and stem clamp are securely fastened. If the stem clamp is
loose, check plug thread engagement (refer to the “Reassembly and Installation” section for
the correct procedure on aligning the plug with the seat). Tighten stem clamp nut.
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