Cashco 964 User Manual
Page 11
IOM-964
11
VII. TROUBLE - SHOOTING GUIDE
SECTION VII
Possible Causes
Remedies
A. Excess packing friction.
A1.
A2.
A3.
A4.
Realign body - stem - actuator.
Packing follower too tight for optional packing designs.
Install positioner.
Increase bench set by changing to stiffer actuator
range spring. Will require positioner if not installed.
May require different airset.
B. Installed backwards.
B.
Install per fl ow arrow.
1. Valve is “jumpy” in stroking.
Possible Causes
Remedies
A. Excess pressure drop.
A.
Bring pressure drop within design limits.
B. Guide bushing wear.
B.
Re place guide bushing.
C. Misalignment.
C.
Realign body-stem-actuator.
2. Valve makes “screeching” noise.
Possible Causes
Remedies
A. Excess pressure drop.
A.
Bring pres sure drop within design limits.
B. Guide bushing wear.
B.
Re place guide bushing.
C. Excessive cavitation in liquid service.
C1.
C2.
Change operation parameters to relieve causes of
cavitation.
Replace valve with valve equipped for cavi ta tional control.
D. High outlet velocity.
D1.
D2.
D3.
Re duce fl ow rate and/or pressure drop.
Use multiple valves in series or parallel.
Increase outlet pipe size.
3. Valve exhibits “excess” vibration.
Possible Causes
Remedies
A. Excess pressure drop.
A.
Re duce pres sure drop conditions.
B. Improper actuator bench setting.
B1.
B2.
Cali brate actuator-to-valve.
Assure proper engagement of actuator stem-to-valve
stem. Adjust as calibration dictates.
C. Metal seat design instead of composition seat
design.
C.
Convert valve to composition seat design.
D. Excess wear.
D1.
D2.
D3.
D4.
D5.
Oversized valve op er at ing too close to seat; go to re-
duced trim.
Incorporate stellite trim.
Remove particulate.
Possible excess cavitation in liquid service. Change
operation parameters.
Re-lap plug-seat surface.
E. Misalignment.
E.
Realign body - stem - actuator.
F. Composition seat failure.
F1.
F2.
Replace soft seat.
Remove "dirty" portion of fl uid causing failure.
G. Seat ring gasket failure.
G.
Replace seat ring gasket.
4. Valve exhibits “excess” seat leakage.