Liquid hammering problem on screw compressor in ammonia refrigeration system

Dear friends in one of my plant there 6 nos. SB series Grasso make screw compressors in which 4 nos. has been running since 10 years and 2 compressor are new just added to the system.All of them are connected by -2 deg c and -5 deg c common header.Suppose i have select 2 existing compressor and 1 new compressor on -5 deg c system. At the same time 1 existing and 1 new compressor are running but the ammonia liquid comes on the existing compressor only.their discharge temp falls down and compressor make abnormal noise while the new compressor are running well. Kindly gives yours valuable suggestion as earliest as posible.

Liquid carry over due to greater swept volume from the comps?
Try lowering your Surge / inter cooler Drum working level.
Is the affected comp nearest the drum suction?

Just a complete guess given the little information you give.
What's a refrigeration executive?
Grizzly

I agree with Grizzly about possible increase in swept volume causing liquid carryover. If you lower liquid level it might help. If it is a low pressure pump receiver be careful not to lower level too much and cause pump[s] to cavitate.

Did you add more end users that required you to add compressors. If so, do any of the end users cause violent flood back of liquid to low presure receiver causing slopover.