17-Oct-2022 Comment by David Wang: On OCt 14th, Replaced a flexible hose on MP1S pump exhaust port,but did not solve the issue. High frequency vibration was sensed by hand on MP1S pump inlet and outlet ports. Pump height and position in pit are adjusted slightly in pit to reduce vibration. After, ITHCG2 and ITW CG4SA got a huge improvement in past 3 days. All back up line pressure are stabilized at normal operation status. Still, close watching on this issue is needed to ensure the present status is stabilized in long term.

The issue was returned after shielding block installation Monday morning at 8:30am. Investigated further,  I temporarily installed a turbopump used cooling fan on MP1s to improve pump heat dissipation. And a room fan is put outside on shielding blocks opening hole to increase air circulation into pit. Since then,  everything is perfect. All secondary turbo pumps current draw is around 0.5 to 0.6A which is the best.  I guess that short duo 10 pump life we observed in past could be related to high pump operation temperature in pit as well. We may increase the pump life if air circulation around the pump could be improved. A permanent solution is needed for it.