On a typical system with an expansion tank, the make-up water line connection point to the chilled water system is the point of zero pressure change. The pressure at this point is the same whether the pump is running or not.
I'm guessing this holds true for a system without an expansion tank.
In your case, the pressure drop on the pump suction, when the pump is energized, should be the same as the water pressure drop (friction, loss through valves, etc.) from the make-up water line connection point to the pump suction.
I'm guessing this holds true for a system without an expansion tank.
In your case, the pressure drop on the pump suction, when the pump is energized, should be the same as the water pressure drop (friction, loss through valves, etc.) from the make-up water line connection point to the pump suction.
