How to calculate chiller pump head

how to calculate chiller pump head
It is the total pressure lost plus 5 to 10 psig: head pressure(vertical piping: you need 0.433 psig to push the water 1 ft height or 1 ft of water,WC, is equal to 0.433 psig)... horizontal piping( it rate in ft of water at per 100ft of pipe) and its associated valves and fittings, and the coil.. . plus you need to know what is your design (intended) flow, you need to get a hold of the chart for friction lost for your pipe and fittings and valves