Ballvalve
General Engineering Contractor
If you look at post #30, I said if everything is static and the pressure rises, the PRV is bad. This is not bad advice.
A bypass, if it exists in the PRV, won't open until the house pressure exceeds the incoming pressure. This could be quite high. Plus, it may not work. An expansion tank is required when the system is closed, and will keep the internal pressure essentially constant. In most places, you have a PRV, you are supposed to have an expansion tank. It will also prevent the house pressure from rises, which was indicated was 130# at the street, which is TOO high, even with a bypass that MIGHT limit it to that value.
Yes, you got that correct, but he doesnt have a closed system, there is no check valve. He does not need the tank. He didnt have it for 20 years. He is with 20 million others in the same situation.
In my experience the bypass opens at some point close to the set-point house pressure, but I have no documentation at the moment to back it up. I do have a few houses with the same situation and with a pressure gauge in the house and I never see a pressure rise even after a 3 week vacation with two water heaters on. Incoming is 100psi and inside stays at 55.
As I noted, an adjustable 1/2" $8 well pressure relief valve set to 80 or 100 psi will announce the regulators demise.
I would buy the Cash-Acme, made in America, cheaper than the Chinese Watts, and get the plumber to come out and install it. Better fit and finish too.