Trouble Shooting-Linear

Sr.No.Description of troubleProbable causePossible Solution
1Less than rated or no valve travel even though proper air pressure is applied to actuator diaphragm.1. No air signal or incorrect air signal to actuator1.Check the controller and correct.
2. Air leakage through the tube wall or connections2.Check the piping system and repair.
3.Rupture on the actuator diaphragm.3.Replace diaphragm.
4. Dirt or foreign matters restricting rotor movement4.Disassemble valve, clean and polish
trim parts.
2Leakage at Body Joint.1.Improper Tightening of the Body-Bonnet Joint.1.Tighten the bolts in a consistent manner.
2. Damage to the body and bonnet flange’s sealing surface.2.Repair the sealing surface of the body or bonnet where damage is observed.
3. Gasket failure or metal sealing ring damage.3.Replace or replace the gasket or metal sealing ring.
3Leakage around valve stem.1. Wear or damage on the packing.1.Replace packing.
2. Extreme wear or damage on the valve stem.2.Replace valve stem.
4Inadequate flow1.Improper plug adjustment1.Refer ‘ASSEMBLY OF VALVE’ section of the manual shared
2.Malfunctioning valve positioner2.Bypass valve positioner and check valve operation with direct signal
3.Service conditions exceeds trim design capacity3.Reconfirm service conditions and contact factory
5Control valve hunting1.Input signal fluctuations1.Provide steady signal through controller
2.Backlash error in moving parts2.Remove backlash
3.Moisture in air line3.Provide dry air supply
4.Improper tuning of controller4.Adjust the controller settings
6Excessive noise1.Flashing or Cavitations1.To ensure that adequate care has been taken at design stage
2.Loose supports2.Tighten the supports sufficiently
3.Damaged trim assembly3.Replace the trim parts
7Handwheel cannot be turned flexibly.1.Damage to the stem nut due to Dirt /Foreign Particle1.Replace the stem nut with a new one.
2. Wear or perforation of the stem nut’s screw thread.2.Clean the debris from the screw thread of the stem nut.
8Gland Leakage1. Packaging is not sufficiently tightened (Gland Nut Loose).1.Equally tighten the Gland nut.
2. Worn out Gland Packing.2.Change the packing with a fresh one.
9Seat Leakage1. Sealing Edge of Seat Damaged1.Replace Soft Seat.
2. Valve Pressurized to High Pressure.2.Reduce Line pressure to rated Pressure.
3. Fluid is abrasive & Eroding away Seal.3.Replace worn-out parts suitable with abrasive Media