Thanks so much for jumping in with some great points and questions.
Here is more information: The valve is a Watts LF25AUB -Z3 2" Details can be found on this page (
https://www.watts.com/products/plum...ves/water-pressure-reducing-valves/lf25aub-z3).
My system is supplied from an unmetered 2" line coming of a Reclamation District main header. I have a 2" ball valve at the main connection then 600 feet of 2" line dropping 100' in elevation to a second 2" ball valve then the pressure regulator followed by a couple of 3/4" tee's and three hose connections. This is all a temporary setup until we put in the irrigation/sprinkler system after the winery is built. Last year I had 85 psi at the line in and the 40' of head increase gave me 125 psi at the pressure regulator. I don't currently have a connection on the upstream side or the PR to measure pressure but since I have water flow and the 100' elevation change physics says I have to have a minimum of 40 psi at the PR and it's highly likely a lot more than that. I do know that when I accidentally opened the 2" ball valve just before the PR and blasted a huge trench in a pile of dirt si I am confident I have unrestricted flow at a fairly high pressure to the PR valve. The internal inlet screen is clean.
Today I tried it a gain and it seems to be working normally but at the lower pressure. When I slightly open one of the hose bibs pressure drops down to zero then quickly recovers to 20. When I open the hose bib fully pressure drops to zero with good water flow. When I close the hose bib pressure bounces up to 30 psi or so then settle in at 20. All would, in my mind, be expected if pressure is set at 20 psi. When I tighten adjusting screw and subsequently the internal spring I would expect the output pressure to increase but it doesn't.