VAF instruments OILCON MARK 6M - 15.9 PNEUMATIC VALVE PROBLEMS

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15.9 PNEUMATIC VALVE PROBLEMS
For repair procedures of pneumatic valves consult section 8.2.5.
15.9.1 Valve not functioning
Probable causes Action
1
No air supply

Check the air supply unit regulator in the air supply line
to the valve, normally set to 4.0 bar (0.4 MPa).
 Check all air connections for leakage.
 Check the ship’s control air system.
 Check the functioning of the solenoid valve. See
section 15.8.
2
Pneumatic valve failure

Check the actuator housing for leakage.
15.9.2 Valve gland leakage
Probable causes Action
1
Worn gaskets

Damaged or worn gaskets or damage of the valve
gland.
Replacement of the gaskets is required.
The unit should be returned to a qualified service
centre for repair.
15.9.3 Valve leakage
Probable causes Action
1
Leakage between the valve plug
and seat

Damaged or worn valve seat and plug.
Replacement of the valve seat and plug is required.
The unit should be returned to a qualified service
centre for repair.