Troubleshooting - Flowserve Valtek VL-C User Instructions

Troubleshooting

Problem
High air consumption or
leakage
Actuator does not move to
fail position upon loss of
air supply pressure
Jerky or sticking stem
travel
10
Probable Cause
1. Leaks in the air supply or instrument signal system
2. Malfunctioning positioner
3. Leaks through O-rings or adjusting screw gasket
1. Air pressure in cylinder not venting because of faulty positioner
2. Spring failure
3. Internal valve problem
1. Insufficient air supply pressure
2. Unlubricated cylinder wall
3. Worn or damaged stem bushings
4. Improperly assembled spring
5. Internal valve problem
Valtek VL-C Spring Cylinder Linear Actuators FCD VLAIM054-01 – 06/13
Corrective Action
1. Tighten connections and replace any leaking lines
2. Refer to appropriate positioner maintenance bulletin
3. Replace O-rings or gasket
1. Refer to appropriate positioner maintenance bulletin
2. Replace spring
3. Refer to valve's maintenance bulletin
1. Check air supply and any filters or regulators;
check for leaking O-rings
2. Lubricate cylinder wall with silicone lubricant
3. Check actuator stem for damage; replace actuator
stem, O-ring, and stem bushings, if necessary
4. Disassemble actuator and check cylinder and piston
for damage; reassemble actuator correctly
5. Refer to valve's maintenance instructions