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Water Pressure Valve Gone bad?

Author: wwwdrew (CA)

Home is built in 1989 with copper plumbing in CA; Two-story, 3000sqft, in case it matters. I just moved into the home so not sure of the history, but the water pressure is currently at 103 PSI in a "closed system" (all fixtures closed); tested at a hose bibb next to the PRV and tested at another hose bibb at the opposite side of the house. Both test at 103. Since the Rainbird Water Pressure gauge seemed a little shakey I exchanged it for a Watts gauge. same results: 103 PSI

I adjusted the PRV (counter clockwise turn) and it definitely lowers the "flow" of water in an "open system" (fixtures opened). Backed off the PRV considerably and the sprinklers and faucets barely work. Tighten it back up (clockwise) and it all works great again. In an "open system", when the PRV is backed off the pressure lowers more (to 20-30 psi) than when it is tightened.

What concerns or confuses me is the Water Pressure in a "closed system" does not go below 103. I would expect backing off the PRV would also lower the PSI in a "closed system" test.

I also closed the valves to the water heaters (two in-line water heaters, each 30 gal.), to help ensure they were not affecting anything. Got the same results.

Before I hassle replacing the PRV, is it likely bad? And out of curiosity, why does the PRV adjustment not lower the water pressure in a closed system but definitely does affect pressure readings when fixtures are opened?

Thanks, and hope I gave enough info without being too wordy.

Re: Water Pressure Valve Gone bad?
Author: hj When you lower the pressure, the original pressure is still in the piping and until you release it by opening a faucet, it cannot go anywhere, You always adjust a PRV with a faucet running. Then, if the pressure increases when the faucet is turned off, the valve is bad.

Re: Water Pressure Valve Gone bad?

Author: wwwdrew (CA)

Thank you much HJ. During the tests, I did try opening and then re-closing the faucet to let the pressure out and the gauge went back up to 103.

However I did not try the same method you described (adjusting PRV with a faucet opened), which makes a lot of sense as a good rule-of-thumb. I just did that test and the same results: PSI back up to 103.

I'll replace the PRV. Again, thanks much for your help.

Re: Water Pressure Valve Gone bad?

Author: sparkitsolution21 (CA)

Excess Pressure in water supply can cross 150psi. We need water pressure decreasing valves on domestic systems where the supply water pressure crosses 85psi. Higher water pressure can damage or crack pipes, break fixtures,and hurt the people using them. So we need to install pressure valve but to keep the pressure valve of we can test water pressure with a gauge.
We can use a pressure regulator.

Thanks

[www.drdrip.com.au]

Re: Water Pressure Valve Gone bad?
Author: sparkitsolution21 (CA) Heavy water pressure cuases the valve to damage, so i think its better to use faucets which fecilitates proper flow. The valve when gets damaged must be changed by a plumber to avoid spilling of water and spreading mess all around. [www.drdrip.com.au]

Re: Water Pressure Valve Gone bad?
Author: sparkitsolution21 (CA) Heavy water pressure causes the valve to damage, so i think it’s better to use faucets which facilitate proper flow. The valve when gets damaged must be changed by a plumber to avoid spilling of water and spreading mess all around. [www.drdrip.com.au]