3 PRV’s in a Row, Plus a 4th down the line, Why?
So 3 prvs in the pump room, a 4th prv located further down the system (serves a dry valve riser water supply). The 2 are in a row after the pump, that feed into the same exact spot in the system side piping.
Then a smaller prv on that smaller middle line, no jockey or anything on that line, it is fed from the same pump discharge piping as the other 2 prvs and it feeds the same exact spot on the system side pipings as the other 2. So you really have three PRV‘s being supplied at the same exact point of the system and relieving pressure at the same exact point of the system.
They also have a prv down the line for the dry riser supply (have a series of dry valves directly above on the floor above).
I am honestly lost on why you would need that smaller prv. I could see needing multiple prvs, especially needing a separate PRV for your dry valve water supply (if it branched off of your discharge side piping prior to a prv, so you would need a PRV for your supply for the dry riser and then a prv for your supply for the rest of the system), but this seems pretty excessive. Especially the small PRV and then having an additional one for the dry riser down the line when you’ve already had the water going through three separate PRVs.
Does anyone understand why that small PRV is in place? Or why they would this building would need 3/4 prvs serving the same discharge piping/point in the system?
I work in test and inspection so my installation knowledge is a little limited and I know the answer could heavily be reliant on hydraulic calculations. I was just wondering if anyone had any insight.