Hi
Hope you have taken all possible steps to locate the leaks , nice. One clarification is required whether checked the connecting pipe between the air evacuation header running in the top near the ST Exhaust duct . There will be minimum 2 to 4 connecting pipes for each module. Sometime found cracks in that causing vacuum drop. Also exactly in the ST exhaust penetrating portion sealing portion also gave problem. All syphon loops, vacuum breaker etc maybe checked. Thanks.Regards
