PRV'S in EPA NET

[jeepeng]

I have got my model up and running, but I'm still having issues, so if someone could chime in on the following I would appreciate it.

My model has a high point and a low point. The low point needs to have PRV'S in place to keep the pressure down. I have 5 prv's in the model all set on 80. Also, the model only has one source, a reservoir with an HGL. I am attempting to tie onto another offices model without fully re-creating their model.

Question Number 1: Is it correct to put the actual pressure you want the PRV set to, or should it be set to an elevation?

Issue #1: the nodes close to the PRV's are at 80, but as I go down the pressure creeps up to 110. This is over 4,500 L.F. and a elevation difference from 5416 to 5360. The PRV is near the 5416 elevation.

Issue #2: only one of my PRV's are opened by the model, all of the others have been closed by the model after I run it. Therefore, I am not getting the flow I think I should be getting because the water is having to come half way around the world to get to the node rather than through the PRV.

I hope that I have been clear and I hope someone can help me.

Thanks Rich

 

[hydrae]

PRV's are set to a pressure which is added to the elevation to get a 'boundary' point hgl, if it can be supplied.
Since your PRV's are set to 80 but are at different elevations only the highest one will be open unless friction losses drop the pressure locally to activate a second PRV.
80 psi would be a high set point for a PRV. A common application for the PRV is pressure entering at 80 psi and exiting at 45 psi.
80 psi being the maximum pressure per the plumbing code and 45 psi being a good minimum target pressure for services to provide full service while allowing for upsets such as fire flows to maintain the minimum of 20 psi

Hydrae