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

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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