Hello,

My water pressure was at 110 psi and I decided to put in a pressure reducing valve with some help from my step-dad. The mainline is coming in so tight to the foundation with a 90 degree angle that we thought it was best to get some clearance from the wall with more 90 degree angles. While we were at it we replaced the main gate valve with a ball valve and the hose bib that is going off to the left. Everything eventually started working and I set the pressure to about 75 psi.

The issue is that there is now a loud whistling/humming sound after toilet flushes or when the washer is filling (heard upstairs and in other finished area of the basement) and it bothers my wife a lot. It was unnoticeable before this but now I'm seeing about 47.5 dB of noise. I thought maybe the PRV was faulty so I replaced it with the same model Zurn 3/4" 70XLDU and had the same results. Is this normal to get this type of noise? What can I do to reduce it? Is this model just noisier than others?

As of now I'm considering getting rid of the PRV since it was fine at 110 psi and the neighbor says he hasn't had any issues for decades with the same pressure. My concern is that it might not even be the PRV now, but all the 90 degree turns we added. It was such a pain sweating all of the copper pipe and my step dad is worried about that initial main 90 degree turn as it's bent on the inside and thinks messing with it too much could cause a leak. It's under the stairs in a void where it can echo, but it must be vibrating to reach farther areas.

Thank you for the help.

1)where is expansion tank????????????
2) 75 psi is too high, lower it to 50


the sound you hear is common then there is no expansion tank, the PRV will allow excessive pressure to back into the public water system. it quite an annoying sound. You "must" have an expansion tank.

one like this, it must be size write

THERM-X-TROL ST-5 Expansion Tank



Edited 1 times.

oopsie if you have a dented and/or 'crimped' fitting installed

take it all apart and redo with 45 degree fittings

or

take it all apart and redo with LONG RADIUS 90 degree fittings



or

call a licensed, insured, bonded plumber

==============================================

"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638

NoHub,

Why does he have to have an expansion tank ?

only if the PRV has a built in check valve

because when water is heated it expands. The Prv acts as a check valve. Read any PRV install info and it will say you need to install an expansion tank.

Thanks NoHub- I do not have an expansion tank, but I plan on installing one now and I'll reduce to 50 psi. Thank you for the help!



Edited 1 times.

Remember...whatever you set the prv at (50 psi is good) you'll have to pump the tank pressure to 50 psi to match it, I just stop at one of those gas stations with the adjustable air pressure gauges on the air station it's really easy, and make sure you get a tank for domestic and not heating...good luck.

FIRST try 50 # setting


'some' PRVs are 'pressure balanced' and do NOT require a compression tank

==============================================

"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638

quote: "As of now I'm considering getting rid of the PRV since it was fine at 110 psi and the neighbor says he hasn't had any issues for decades with the same pressure."

high pressure = higher velocity = more power to erode your copper piping.
also way higher risk of having a supply line rupture in the home - probably when you are gone on vacation.

Your step dad did a very nice job. Installing plumbers were dumb with that 90 buried in the concrete.
If it was me that did that work I would have planned on the new copper piping to be 1-5/8" off the concrete so I could I install strut and a strut clamp. The weight of the new valve, new PRV, pipe and fittings is now all being supported by one soldered 90 fitting.



Edited 2 times.

Quote

..... Watts makes a PRV with a standard bypass feature - which I'm guessing means no thermal expansion tank is needed. .....

PRECISELY


albeit, technically: it is a thermal expansion relief port a/k/a 'small hole/orifice in the disc'




==============================================

"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638

bernabeu, it works but a horrible feather. You get some very loud and annoying sounds from the PRV and the Pressure goes really high before it starts to creep down. It also beats the hell out of and shortens the life of the unit in my eyes. No Plumber I know just installs a PRV without an expansion tank.

I did not recomend it (for typical residential use), I merely confirmed its existence.

Said valves are WIDELY used in situations where there is continuous, or nearly continuous, cold water usage.

==============================================

"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638

Pressure reducing valves have rubber that eventually cracks and seats that need to be replaced. They must be maintained or you have problems

I reduced the pressure to 50 psi, and finally installed an expansion tank set to 50 psi above the water heater tank on the cold side. This unfortunately didn’t fix the noise from the pressure reducing valve. What else could I try to reduce the whistling noise? Is this some kind of resonant frequency?

try one of these:

"The innovative design also eliminates the water whistle or harmonic hum associated with most PRVs, thanks to innovative "micro-fingers" that dissipate noise as water flows across the seat."
EB25 Double Union PRV



available through our sponsor: [www.plumbingsupply.com]

==============================================

"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638

I put in an EB25 and it helped significantly. Thank you so much! There’s just a bit of leftover noise that I will try to reduce with some hangers or pipe insulation.



Edited 1 times.