Troubleshooting Guide - Flowserve Valtek Valdisk User Instructions

12 Troubleshooting Guide

Scenario
Valve moves to failure position excessive
air bleeding from transfer case
Jerky shaft rotation
Excessive internal leakage
(Shutoff/Seat leakage)
Leakage through pipe flange line gasket
Leakage through packing box
Disk interferes with body
Disk interferes with pipe flange line
Valve slams, won't open, or causes
severe water hammer
Shaft rotates, disk remains open or closed
Actuator operates, shaft does not rotate
VAIOM000286-02 (EN/AQ) May 2023
Valtek Valdisk High-Performance Butterfly Control Valves
Causes
Failure of actuator O-ring
Failure of sliding seal assembly
Overtightened packing
Improper adjustment of lever arm on shaft
causing arm to contact transfer case
Cylinder wall not lubricated
Worn piston O-ring allowing piston to gall on
pneumatic actuator cylinder wall
Worn actuator stem O-ring causing actuator
cylinder stem to gall on stem collar
Worn (or damaged) shaft bearings, shaft
bearings or packing followers
Improper adjustment of external stroke stops
Worn or damaged seat
Damaged disk seating surface
Improper handwheel adjustment acting as
limit stop
Loose pipe flange bolts
Worn or damaged gaskets
Dirty or corroded gaskets
Loose packing box nuts
Worn or damaged packing
Dirty or corroded packing
Packing follower contacting the anti-rotation
ring
Disk installed upside down
Worn shaft bearings
Cement lining or heavy schedule pipe
Improper valve installation
Missing or broken taper pins
Broken internal actuator parts
Broken internal actuator parts
Table 5: Troubleshooting recommendations.
Remedies
Replace actuator stem O-ring
Repair or replace sliding seal assembly
Retighten packing box nuts to slightly over
finger-tight
Readjust lever arm (see step 1 in the
"Remounting Actuator" section)
Lubricate cylinder wall with silicone lubricant
Replace O-ring: if galling has occurred
replace all damaged parts
Replace O-ring: if actuator stem is galled
replace it
Disassemble and inspect parts; replace any
worn or damaged parts
Refer to the installation, operation, and
maintenance manual for corresponding
actuator
Replace seat
Replace disk and shaft
Adjust handwheel until disk seats properly
Tighten pipeline bolting to required torque,
Refer to Annex A
Replace pipe flange gaskets
Replace pipe flange gaskets
Tighten packing box nuts
Replace packing
Clean body bore and stem, replace packing
Add a 0.25 spacer or more packing to
prevent contact
Inspect, replace if damaged and Reinstall
disk
Replace shaft bearings
Modify line to allow proper disk clearance
See step 2 in "Installation" section and
correct flow direction
Replace taper pins
Replace shaft, make sure shaft is not
overstressing on external stroke stop
Refer to appropriate actuator Maintenance
Instructions
Page 18 of 22