Determining existing Chilled Water System Min and Max Differential Pressure

[ReyB]

Hello,

I'm trying to modify the current controls of the chilled water pump on my project that run on a fixed differential pressure setpoint. I'd like to reset the setpoint from min to max depending on the AHU valve position. However, I don't have a water balancing report that will tell me the minimum and maximum DP of the chilled water loop. I remember in the past I was able to find this value by doing a test on the system through the AHU chilled water valves. Does any one here knows the exact process of determining the min and max DP by doing the test of some sort? Thank you.

Best Regards,
Brian

 

[HVAC-Novice]

How many branches with control valves do you have? Do you have a reliable flow meter?
If you control target dP based on valve positions, technically the maximum pressure setpoint is just to stabilize the loop and a safe keep in case the valve or coil has a problem. Valve typically controlled based on DAT. So if the DAT sensor fails, valve would just stay open since it doesn't know set point is already met. Pump would maintain that max pressure.