How to remove air from running chilled water system

[ashsabi2006]

we have 1100 tons chilled water system which was recently been drained for tie in of chilled water line for the expansion of accommodation building after that water was filled during water filling & after startup of chillers we were purging air from the systems for about 10 to 15 days & then there were no air coming from the air vents. we thought that system is free from air & since it was winter there where no cooling issues. But Now in summer less cooling in rooms complain started coming 7 we observed there is still air in the system. Accommodation complex consist of 6 blocks of ground +1st floor with approximately 300 rooms & 30 AHUs.please advice the best way to remove air from the system. Accommodation complex consist of 6 blocks of ground +1st floor with approximately 300 rooms & 30 AHUs

[timebuilder]

Bleed the remaining air from each of the 30 air handling units individually.

After doing so, recheck the main system at the top.

Don't forget to check your water chemistry.