| Area | Purpose | Procedure | Frequency |
| Body | Prevention of leakage and improper action. | Visual check of seating surface and gasket contact surface for damage. | At the time leak is detected or every four (4) years. |
| Disc | Prevention of leakageat seat and improper action. |
Visual check of seating surface for damage. |
At the time leak is detected or every four (4) years. |
| Stem, PackingWasher& Gland |
Prevention of Stem and packing leakage and improper action. | Visual check for scoring and seizing, especiallyalong sliding surfaces of stem and packing. | At the time leak is detected or every four (4) years. |
| Bolts &Nuts |
Ensure proper tightness of joints. |
Check for tightening force or retightening. |
At the time looseness is detected or everyfour (4) years. |
| Packing |
Prevention of leakageand improper action. |
Check the Gland bolt for looseness and retighten as necessary.Replace packing. |
At the time of leak or every two(2) years. |
| Gasket |
Prevention of leakage |
Check the nuts and bolts for looseness. Retighten as required. Replace the gasket. |
At the time of leak or every two(2) years. |
| Seal Ring |
Prevention of leakage |
Check nuts and bolt for looseness and retighten as necessary.Replace SealRing |
At the time of leak or every two(2) years. |
| Problem | Cause | Repair Procedure |
| Packing Leakage |
PackingCompression Worn Packing Stem Damage Stuffing Box Damage |
Tighten Packing Replace Packing Repair or Replace Stem Repair Stuffing Box |
| Body-Bonnet/ Cover JointLeakage |
Insufficient Bolting Tightness Gasket Worn or Damaged |
Check Bolting Torque Replace Gasket |
| Seat Leakage | Damaged Seating Surfaces | Lap Disc and Seat Ring |
| Stem Binding |
Insufficient Lubrication Packing Too Tight Damaged Stem Threads Damaged Sleeve |
Lubricate Stem Adjust or Replace Packing Repair or Replace Stem Repair or Replace Sleeve |
| Valve Seat Leakage when fully closed | Differential pressure is larger than design condition Inadequate method of stopping valve Damage to valve seating surfaces |
Decrease differential pressure Change method of stopping valve
Change method of stopping valve Disassemble valve and lap seating surfaces |
| Seat Leakage | Damaged Seating Surfaces |
Lap Disc and Seat Ring |
| Motor does not start operation | Wrong electric power supply source or low voltage Damage to motor due to buring, Disconnection of wire and deterioration of insulation Differential pressure is larger than design condition |
Change to proper electric power supply source Exchange motor Decrease differential pressure |
| Motor stops during middle of opening or closing operation | Improper lubrication of threaded of stem
Galling in threaded part of stem Galling or foreign matter in sliding parts inside of valve |
Clean up threaded part and apply grease Lap engagement of threads or replace stem and stem nut Disassemble valve, inspect and repair the sliding part |