I am trying to understand how to solve the hydraulics for looped mains. If I have a system that has a looped main and two zones are opened and I have to figure the head pressure for a certain head. The head in question is closer to the main and meter that the other zone that is running. Do I figure the total gpm for the farthest zone all the way to the main line that has the zone operating that I need to now the head pressure and then figure the loss with of total gpm and pressure loss to the main? We did not cover this in class and when asked this in the state test I really had no way of knowing how to start. I am taking a refresher class on Dec. 12 and then the retest on Dec. 15 and would like to pass this time. Thanks in advance.