Malfunction:
1. Leakage of the sealing surface, discs and seals of the butterfly valve are mixed with debris.
2. The disc ,seal of the butterfly valve close position is not correct.
3. The outlet of the flange bolts are either forced imbalanced or not pressed.
4. The pressure test direction is not as required.
Elimination Method
1. Eliminate impurities, clean the valve cavity.
2. Adjust the limit screw of the actuator such as worm gear or electric actuator to achieve the correct closing position.
3. Check with the flange plane and bolt compression force, should be uniform compression
4. Pressure test in the direction of the arrow
Fault: Leakage at both ends of the valve.
4.1 The gaskets on both sides fail.
4.2 The pressure on the flange of the pipe is not uniform or not pressed.
5. Elimination method:
5.1 Replace the gasket.
5.2 Press the flange bolt (uniform force).
