Cooling water network simulation

Hi there, I have created a EPANET model using its guide and tutorials. But can not understood correctly that, which vale I should use to indicate exchanger. I used GPV type and entered pressure drop which I actually found but flow going through it is high.
Another option I had that to use FCV with fix flow. It is slowing same flow as I require but unable to confidently say that what I did is correct.
please guide me in this matter.