Hi,
We have a chilled water system. Primary pump loop and secondary pump loop. There are three secondary loop pumps "pumps are supplying the buildings". They the pressure gauge at every pump is reading 100 psi at their suction and 48 psi at their discharge. We do not have high pressure head and according to our calculations it should be around 50psi. The primary pumps have a pressure of 45 psi at each pump "there are three pumps". My question is: why the pressure before the secondary pumps is high? Does this mean that the secondary pumps selection is wrong? could it be that the secondary pumps gallon per minute is smaller than what is running through them?
Please help

Thank you

Mack