Table Iii: Troubleshooting Chart - Flowserve Valtek Mark Two User Instructions

Problem
1. Over-tightened packing
2.
Stem motion impeded
3. Inadequate air supply
4. Malfunctioning positioner
1. Improperly tightened bonnet
2. Worn or damaged seat ring
3. Worn or damaged seat or bonnet gasket
4. Inadequate actuator thrust
Excessive seat leakage
5. Incorrectly adjusted plug
6. Improper flow direction
7.
8. Worn or damaged pressure balanced seals
9. Inadequate air supply pressure
1. Improper plug adjustment, limiting stroke
2. Malfunctioning positioner
3.
Inadequate flow
4. Incorrect actuator stroke
5. Inadequate air supply pressure
1.
Plug slams
2. Inadequate air supply
3. Trim sized too large for flow rate
1. Incorrect flow direction
Valve does not fail in
correct position
2. Incorrect actuator fail direction
Valtek Mark One and Mark Two Control Valves FCD VLENIM0001-02-A4 - 05/16

Table III: Troubleshooting Chart

Probable Cause
Service temperature is beyond operating
limits of trim design
. Improper handwheel adjustment acting as a
limit-stop
Service conditions exceed trim design
capacity
Incorrect plug adjustment allowing improper
cushion of air between actuator piston and
yoke
Corrective Action
Adjust the packing box nuts to slightly over finger-tight
Reconfirm service conditions and contact factory
Check for leaks in air supply or instrument signal system;
tighten loose connections and replace leaky lines
Refer to positioner User Instructions
Refer to step 7.11 Assembly and Installation section for
correct tightening procedure
Disassemble valve and replace or repair seat ring
Disassemble and replace gaskets
Check for adequate air supply to actuator; if air supply is
adequate, reconfirm service conditions and contact factory
Refer to steps 7.9 to 7.11 Assembly and Installation section
for correct plug adjustment
Refer to original specifications or contact factory
Adjust handwheel until plug seats properly
Disassemble and replace pressure balanced seals
Check for leaks in air supply or instrument signal system;
tighten loose connections and replace leaky lines
Refer to steps 7.9 to 7.11 Assembly and Installation section
for correct plug adjustment
Refer to positioner maintenance instructions
Verify service conditions and consult factory
Verify actuator stroke
Check for leaks in air supply or instrument signal system;
tighten loose connections and replace leaky lines
Refer to steps 7.9 to 7.11 Assembly and Installation section
for correct plug adjustment
Check air supply to actuator; repair leaks and remove any
restrictions in supply line
Verify the service conditions and actuator sizing, install
reduced trim
Reconfirm direction and, if necessary, correct flow direction
through valve
Consult actuator User Manual and change fail direction
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