Manual Valves
1. Manufacturing defects in body, bonnet, stem, and wedge.
2. Leakage through body or bonnet joints under normal operating pressure.
3. Coating/lining defects (if factory-applied).
4. Proper operation of handwheel/gear actuator under rated conditions.
1. Wear and tear on sealing surfaces due to abrasive/slurry media.
2. Damage from cavitation, water hammer, or operation outside design pressure/temperature.
3. Corrosion/erosion due to aggressive chemicals not specified at ordering.
4. Improper storage, installation misalignment, or lack of periodic maintenance.
5. Use of non-OEM spare parts.
1. Body casting/forging defects.
2. Leakage through body joints or seat under rated service conditions.
3. Handle/lever mechanism integrity under normal use.
4. Surface coating defects.
1. Seat wear from abrasive particles.
2. Damage due to overtightening beyond torque limits.
3. Failure caused by continuous throttling (ball valves are isolation valves).
4. Chemical attack from unapproved media.
5. Freezing damage due to retained liquid.
1. Body, cover, and plug casting defects.
2. Leakage past seats under rated operating conditions.
3. Gland packing performance (if installed correctly).
1. Wear from high-cycle or abrasive service.
2. Damage from lack of lubrication (in lubricated plug valves).
3. Misalignment from incorrect installation.
4. Thermal shock from sudden temperature variations.
1. Fabrication and welding defects in gate frame and leaf.
2. Leakage beyond permissible limits at closed position.
3. Corrosion protection (galvanizing/epoxy) defects.
4. Proper functioning of lifting mechanism (manual/gearbox).
1. Damage from debris jamming in sealing surfaces.
2. Distortion from uneven loading or improper anchoring.
3. Damage from impact, flooding, or overtopping.
4. Operating outside rated head pressure.
1. Body and disc casting/forging defects.
2. Leakage past seats within specified leakage class.
3. Shaft and bushing integrity under normal use.
4. Coating/lining defects.
1. Seat wear from throttling abrasive/slurry fluids.
2. Damage due to excessive torque or improper actuator installation.
3. Cavitation/erosion damage outside design limits.
4. Failure due to reverse pressure or vacuum if not designed for such service.