By retrieving data further, It has been found no directly relationship between IG1S surging and dump plug water opening. Vacuum surging is 10minutes ahead dump water supply to circuit. SEE attachment 1. Also, The ITE IG1S start to behavior unusual in middle of Feburary. See attachment 2. Today,  ITE IG1S is still slowly climbing up. I decide to leak check ITE vacuum vessel. Before  leak check, for more information and trouble shooting. I closed water supply to ITE to see if vacuum has response on it. I will return water supply to ITE  tomorrow morning.

Water supply to ITE is returned this afternoon at 2: 10 PM.  Everything works fine so far

I leak checked ITE secondary vessel vacuum. A leak have been found in March 09th noon which is located between entrance module and TM2 top tank flange o-ring seal( on tank flange). It could not be confirm on which side of the o-ring the leak is from.

During last night, ITE IG1S reading went back to normal low E-7 range and stays in this range now. So I leak checked same area again this morning. The leak disappeared now. The o-ring works sometime , but not all the time. The plan for this issue: Change ITE target module side o-ring when TM2 is move out., and watch on the ITE IG1s when TM4 is moved back to ITE and pumped down.