I have several PRV's in my model and most of the PRV's have a 2" loop (bypass). Should I try to model the bypass, or should it be ignored in the modeling?
It is not uncommon to have two PRV's in a vault. It is best to model this as one effective PRV because two PRV's next to one another have a bad influence on convergence.
Most of the time, the setting on the small valve will control discharge. However, when there is a big demand, like a fire, the pressure will drop and the big one will open. For example, the small PRV will hold the pressure at 65 psi, but when it can't hold this pressure and the pressure drops to 60 psi, the big one will open. If you are going to use two PRV's, you will need to guess at which one is in control before you start a run.
How does the Pressure Reducing Valve (PRV) work in WaterGEMS and WaterCAD?