Water pressure regulators come in some different types
Standard: (3/4 inch brass or plastic cylinders female & male hose conneciton on end)
These do regulate pressure to around 50 PSI, but they can not handle full flow and thus restrice.
HI-Capacity or HI-Flow,, like above but either wings on body (Camco) or bright plastic grip on female end,, Better, but not much
Sur-Flo, often used as the inlet regulator on Motor Homes and trailers with built in pressure regulators.. Much better when new, but read on Still not 100%
Watts, Valterra or Zurin.
Valterra is an adjsutable with gauge sold for RV use, I have not had a chance to test one but others say it is good and I trust them.
Watts, the smallest one is basicaly the same as the sur-flo, Good, but not quite 100%,, Mine was 3/4 inch New it was very nice.
Zurin, mine is a 3/4 inch (See note below).
Testing: Hooked up the Sur-Flo, as I recall it went down to 10 or 20 PSI under load (Adjusted for 50 static), Now I recall testing 3 regulators, But my Watts is damaged and missing a part (must have had the part that day).
The watts held at 20 under load (50 static) it is nearly 9 years old, it worked much better new.
The brand new ZURIN Rock solid at 50 under load
Load was the outside shower Full open.
So the answer is yes.. They do wear out and begain to restrict flow.. The Watts I have taken apart so I can describe it.
A spring presses on one side of a diaphragm. Water pressure on the other side. (Outlet side pressure) when the spring pushes harder it opens a valve, When outlet presure goes back up the valve is closed.
THEORY: The Diaphragm gets "Stiff" with age. and thus is harder to bend, This will not affect static pressure, but as the outlet pressure drops it means the valve does not open as far.
Why 3/4 inch instead of 1/2 inch.... Turns out they cost less, plus the adapters are easier to fit. But lower cost is the prime factor on the last one.
