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