Hi, Priti,
Just I few quick sugestions.

1/Refrigerant charge
2/Expansion valve/level control problem
3/Reduced water flow due to dirt blocking a pump strainer
4/Damaged pumped.

I would try to establish pump flow rates on the Glycol/Brine side. If you have a flow meter on your system this is very simple, otherwise you are depending on commisioning data, such as temps in and out of the chiller and pump Amperes.
Regards. Andy.