Thank you very much for your kind suggestion.
For comments on increasing air pressure at the actuator, we have tried rising the pressure to 6 bar (25% increase from normally 4.8 bar), unfortunately, this could not help.
For comments on valve siezed, it might be possible. However, why the...
We have found one 18” Metaltite ball valve (full-bore, fail-close), from KTM, cannot be operated (cannot command to open), even though the equalize valve was already opened and the differential pressure across the valve was already 0 bard. Please be noted that there was no fault in actuator...
