After I flush the toilet, use the shower, or run the washing machine, there is a loud screaching/moaning noise coming from my prv. I can even feel the vibration in the cold water pipe in my garage. I assume this is water hammer. The guy at Lowe's said I needed an anti-water hammer device so I bought it. I can't remember what it's called but it looks like about a 4 inch copper tube and it captures added pressure in the water line.

Well, I shut off the water supply, opened a faucet to drain the line, and crawled up under the house to install this thing after the prv but wouldn't you know it: my fittings were too small. Funny thing is, when I turned the water back on so I could come back to it later, the noise had stopped. That was a week ago, and now it's back and louder than ever.

My questions are these:
1. Will I need to install a new prv (is this one clogged up or something?).
2. Is the prv okay but just needs adjusting? How much and how can I tell when it's okay? Just flush the toilet and adjust until the noise stops I guess?
3. Did the Lowe's guy know what he was talking about, and should I try to install this thing anyway (once I get the right sized fittings) immediately after the prv? Or should I just put it aside for now?

Thanks to anyone who can help. This noise is starting to annoy me pretty bad.

After I flush the toilet, use the shower, or run the washing machine, there is a loud screaching/moaning noise coming from my prv. I can even feel the vibration in the cold water pipe in my garage. I assume this is water hammer. The guy at Lowe's said I needed an anti-water hammer device so I bought it. I can't remember what it's called but it looks like about a 4 inch copper tube and it captures added pressure in the water line.

Well, I shut off the water supply, opened a faucet to drain the line, and crawled up under the house to install this thing after the prv but wouldn't you know it: my fittings were too small. Funny thing is, when I turned the water back on so I could come back to it later, the noise had stopped. That was a week ago, and now it's back and louder than ever.

My questions are these:
1. Will I need to install a new prv (is this one clogged up or something?).
2. Is the prv okay but just needs adjusting? How much and how can I tell when it's okay? Just flush the toilet and adjust until the noise stops I guess?
3. Did the Lowe's guy know what he was talking about, and should I try to install this thing anyway (once I get the right sized fittings) immediately after the prv? Or should I just put it aside for now?

Thanks to anyone who can help. This noise is starting to annoy me pretty bad.

Hi Greg,

The Lowe's guy sold you a shock absorber/air chamber,(see image) for water hammer. Unfortunately you do not have water hammer which is a loud "bang" when you shut the water off or close a faucet. What you have is "chatter" and is completely different. Chatter's caused by a loose object vibrating against a seat as the water rushes by. Something's loose in your pressure relief valve and you are faced with two options. (1) Replace the prv valve or (2) open it up and find the loose object. Let me know, Tom

Thanks for the help Tom. I'll be crawling under again in a day or two (I'm dreading it since it's a tight squeeze and about a 30 ft crawl). I will return here to tell my results so maybe someone with a similar problem can get some advice.

Thanks again,
Greg

Well, I replaced the prv yesterday and no more noise. Thank God, it was driving me nuts and waking me up when the wife got ready for work in the mornings.

I learned another valuable tidbit in doing this: CPVC cement does not work well on the white water line (not sure what that is called). I hooked it up once using the CPVC cement and had a leak at one of the joints of white pipe. So I went back to the hardware store for more fittings (buy twice as much as you think you'll need--it's cheap anyway) and got the multi-purpose cement. Worked great and would work better if I could wait the recommended 24 hrs before exposing the line to pressure. Who could do that unless the house was being built at the time of glueing and nobody would be using the water anyway?

So thanks for the help Tom and I hope this experience helps someone else.

Well, I replaced the prv yesterday and no more noise. Thank God, it was driving me nuts and waking me up when the wife got ready for work in the mornings.

I learned another valuable tidbit in doing this: CPVC cement does not work well on the white water line (not sure what that is called). I hooked it up once using the CPVC cement and had a leak at one of the joints of white pipe. So I went back to the hardware store for more fittings (buy twice as much as you think you'll need--it's cheap anyway) and got the multi-purpose cement. Worked great and would work better if I could wait the recommended 24 hrs before exposing the line to pressure. Who could do that unless the house was being built at the time of glueing and nobody would be using the water anyway?

So thanks for the help Tom and I hope this experience helps someone else.

Thanks for the input Greg.

Glad you're all fixed up. Regards, Tom