Air centrifugal compressor surging issue

[Moutaz Hamed]

Hello,
I'm working at Ammonia plant and we are suffering from surging of Process Air centrifugal compressor so I would like to ask about the balance line from the balance piston to the suction

 

[georgeverghese]

Pls repost in Mech Engineers / Gas Compression Forum, and also state what is the concern with balance drum/piston / line.