VAF instruments OILCON MARK 6M, Technical Manual

Page: 102 / 175

101
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.