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ari_one 08-22-2012 01:32 AM

Foghorn sound after install of PRV
New to the forum, so thanks to any replies. I'm in Arizona and last week on Thursday I had a plumber come and install 1) a new electric water heater and 2) a pressure reducing valve (watts x65b). The PRV was installed on the 1" line outside where it comes into the house. There is now the PRV, new shut off ball valve, t to house and other side to hose bibb (old). The pressure was above 80psi before the prv and the prv came pre-set at 50psi. All was fine for first 12 hours but late at night when turning on a faucet in the bathroom a foghorn sound was evident while faucet was on. It got worse the next morning. If flushing or showering no sound, only when opening a single faucet. If opening two faucets at one time then only sound when opening and closing. I called the plumber and talked him into coming and replacing the PRV. All was well for about 24 hours, then the same routine started. Now the plumber has talked with his boss and wants to come change out my toilet fill valves, if it stops the problem I will have to pay $125, if it doesn't then I don't have to pay. I've recently changed both valves.


bob22 08-22-2012 07:54 AM

With a PRV you need to have an expansion tank in the system. Do you know if you have one?
If not, I'd get that installed and see if the fog horn disappears.
Expansion tank allows for the increase in pressure that results from hot water being heated in your water heater. Your system with the PRV is a closed one and the pressure increase needs to be addressed. Otherwise, your temperature/pressure relief valve on your water heater could start to discharge water (as designed).

ari_one 08-22-2012 10:40 AM

Thanks for the input Bob. The watts x65b does have a "Bypass feature in spring cartridge assembly controls thermal expansion pressure" so as I understand it I don't need an expansion tank.

TheEplumber 08-22-2012 10:49 AM

199 Attachment(s)
What does a toilet flushvalve have to do with a noisy faucet?
Test the water pressure at the water heater's drain valve to verify the expansion design in the PRV is working. Also verify the PRV factory pressure setting.
Partially closed fixture shut off valves can make the noise you describe too- make sure they sure 100% open

ari_one 08-22-2012 01:20 PM

Checked the water pressure at the rear of the house and it is 55psi on my gauge, couldn't check it at the water heater because my gauge hits the drip pan when trying to screw it in. I'll try to find and extension after work today to see if I can measure there too. Verified that all sink, toilet, washer, etc. valves are fully open. As I went through every thing I hadn't thought about the anti-siphon unit going to the pool, it is 15 years old, but have no idea how to test to see if that could be the culprit.

ari_one 08-24-2012 12:08 AM

Ok, I just replaced the anti-siphon unit for the pool cause at least one of the ball valve was broken. Also got an extension on the water heater drain and it is currently measuring 2 psi more than the pressure at the rear of the house. The fog horn sound is still there but not as noisy at this point in time. If there is a change I'll post back. Any other ideas??

ari_one 08-31-2012 11:00 PM

I removed the cartridge on from the PRV and put it back on this time just hand tightening it. It helped for a day and a half but the noise started to come back. Did it again and repositioned the metal strainer and it again helped for a few days but sound started coming back again. Talked with my plumber and he came back out and changed from the X65B to a N45B and now the sound is gone. I believe the N45B is a cheaper unit and not as precise on the pressure but the fog horn sound is completely gone :) So for us it was two different watts X65B both making noise, now replaced and noise gone.

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