Flowserve Valtek ShearStream HP Control Valves - Manual (Page 11)

®
User instructions - Shearstream HP - VLENIM0027-01 03.08

Table V: Troubleshooting ShearStream Ball Valves
Failure Probable Cause Corrective Action
Valve moves to failure position,
excessive air bleeding from
transfer case
 Failure of actuator stem O-ring  Replace actuator stem O-ring
 Failure of sliding seal assembly  Repair or replace stem adapter/
linkage assembly
Jerky shaft rotation  Overtightened packing box  Retighten packing box nut to slightly
over finger-tight
 Improper adjustment of lever arm on
shaft causing arm to contact transfer
case, thus failing to convert torque
 Readjust lever arm; see actuator
maintenance instructions
3 Actuator cylinder wall not lubricated 3 Lubricate actuator cylinder wall with
silicone lubricant
4 Worn piston O-ring allowing piston
to gall on cylinder wall
4 Replace O-ring; if galling occurred,
replace all damaged parts
5 Worn actuator stem O-ring causing
actuator stem to gall on stem collar
5 Replace O-ring; if actuator stem is
galled, replace it
6 Worn (or damaged) thrust bearing,
shaft bearing or packing followers
6 Disassemble and inspect parts; replace
any worn or damaged parts
Excessive leakage
through seal
 Improper adjustment of external
stroke stops on actuator
 Adjust the external stroke stops; see
maintenance instructions
 Worn or damaged seal  Replace seal
3 Damaged ball sealing surface 3 Replace ball (and shaft, if worn)
4 Improper handwheel adjustment
acting as limit-stop
4 Adjust handwheel until ball seals properly
5 Ball not centered in body I.D. 5 Center ball; replace damaged seals
Leakage through
line flanges
 Dirty line gasket surfaces  Clean gasket surfaces, reinstall valve
 Worn gaskets  Replace gaskets
3 Improper torque on line flanges 3 Tighten line flanges evenly and comp-
letely (see Table I for proper torque)
4. Flange or pipe misalignment 4 Realign flanged ends with piping
Leakage through packing box  Loose packing box nuts  Tighten packing box nuts over finger-tight
 Worn or damaged packing  Replace packing
3 Dirty or corroded packing box 3 Clean body bore, stem, replace packing
Valve slams, won’t open, or
causes severe water hammer
 Improper valve installation  See step  in the “Installation”
section and correct flow direction
Shaft rotates, ball remains open
or closed
 Broken shaft  Replace shaft
Actuator operates, shaft does
not rotate
 Broken internal actuator parts  Refer to appropriate actuator
maintenance instructions