all was well until
Waterline replaced outside of home along with PRV (2 times in 2 days brand new - watts brand).

Current values:
street pressure - ~180psi
PRV preset - 50psi
expansion tank psi - 49.5 ( checked with pressure gauge, no bleeding) tapping tests shows no problems.

Problem: when water not used for a while psi creeps up to 70-80psi.
while using or soon after using water psi = 50. then very slowly it creeps up.

one scenario: psi measured inside 75. flush toilet. psi comes down to 45. water meter gauge spins at normal speed, when toilet water refills. psi reads 50 then magic happens - it does not stop there. watermeter starts rotate very slowly, can hear hiss sound from near the prv/meter area (meaning water is very slowly flowing). this process continues until 70+ psi then spinning stops, hiss sound stops. psi steady.

any expert help please. desperate.

 

What model PRV? You may need to use two PRVs in series since your inlet pressure is so high. First valve from 180 to 90 say, and second down to 50. Watts recommends this when ratio approaches 4 to 1 and you are pretty close to that.

 

Thanks.
Model i use is 3/4 LF25AUB-Z3.
I hear you. No one does double PRV around here though. I also had single PRV all these years. PRV life goes shorter to 7-10 years. but it did work until the recent waterline PRV/replacement.