MY4CY, MY4

Common issues

• Seat or seal wear causing internal leakage when the valve is closed
• Stem seal or packing leakage to atmosphere
• Seizure or stiff operation from corrosion, scale or deposits
• Ball or seat damage from abrasive particles or debris in the line
• Handle, actuator or position indicator looseness or damage
• Body or end-connection corrosion where the valve is exposed to seawater or humid air

Inspection checklist

• Operate the valve through its full travel and check for smooth movement
• Inspect the stem seal and body joints for leakage
• Check the valve for internal leakage when closed, using downstream test or pressure decay
• Inspect body, connections and fasteners for corrosion and damage
• Check the handle or actuator and the position indicator for correct operation
• Verify that markings and identification plate are legible and match the approved type
• Confirm that the valve is correctly positioned in the line and that supports are intact

Service intervals

Typical wear limits

Ranges are typical for this design class. Always confirm against the manufacturer documentation for your serial number.

Critical spares

• Seat and seal set matching the valve type
• Stem seal or packing set
• Gaskets for body and end connections
• Spare handle or actuator fitting
• Fasteners matching the original material

Safety

• Relieve pressure and drain the line before opening the valve
• Hot, toxic or flammable media require isolation and appropriate PPE
• Do not use cheaters on the handle - stems and balls can be damaged
• Valves in fuel lines are part of fire safety arrangements and must close reliably

Class survey

Held under DNV type approval certificate TAP00002K1 as a ball valve. Surveyors typically check that valves in class-relevant piping carry the right approval and markings and that remote and quick-closing functions, where fitted, operate; pressure test records after overhaul are commonly requested.

Estimated lifetime: Not applicable in running hours; seat and seal life depends on cycle count, media and operating conditions, with the body expected to last for the vessel's service life when kept free of corrosion.