Ask Me Help Desk - Unground sprinklers very noisy

I found what may be an answer to my question but need help to figure out if it in fact is. Someone asked a few years ago what was causing noise in house and was told that a Double Check. What does a double check look like and where would it be installed? Also Would a Pressure Reducing Valve be necessary in all sprinkler systems? We have 3/4 inch copper pipe inside and outside. Thanks for any help.

Sorry didn't proof my question. Other poster was told a Double Check probably wasn't installed. Here's the other post and answer. Quote:
Originally Posted by spid4me
House is on city water in San Jose, CA. All plumbing inside (1/2") and outside (3/4") is new copper pipe except sprinkler pipes (3/4" PVC). Each sprinkler station has anti-siphon valves.

There is a continuous loud noise like water is rushing or gurgling in all pipes inside house for the duration when sprinklers run. Noise comes only if main valve for sprinkler line is half open. If sprinkler's main valve is completely open then there is no noise while sprinklers run. I do not want to open it completely as sprinklers throw water too high and more water is wasted. I will try adjusting sprinkler heads to see if that helps but am wondering if there is something basic wrong with plumbing.

Thanks
Aside from the woefully under sized piping in the house -- It sounds like the installer omitted the Double Check on the sprinkler system.

And no -- The anti-siphon valves are not the same thing.

Also -- A properly calibrated Pressure Reducing Valve (one with a 15 to 25 PSI pressure range) on the sprinkler system would negate the need to limit the flow via the shut-off valve.

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Originally Posted by ;

What does a double check look like and where would it be installed?

A double check valve is just another name for a
Backflow preventer, (see images) and, by all codes, you should have one installed on your water service to avoided contaminating the water in your house.

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where would it be installed?

A backflow preventer or double check valve installs just after the meter on your water service line.

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Would a Pressure Reducing Valve be necessary in all sprinkler systems?

A PRV valve is used to lower your house PSI from high pressure coming from the city main to a acceptable PSI for home use. What's the PSI coming into your home. It sounds like it might be too high. The average home PSI ranges from 40 to 80 PSI with the average being 45. They make a hose bib pressure gage and I would like you to get one and let me know how much house pressure you have.

The noise sounds like it may come from the valve, Have you tried replacing it? Let me know about the Pressure. Cheers, Tom

In addition to Tom's response...

What kind of noise is it ? Is it water friction noise ? Or banging noise ?

Milo did you miss the part where he said,

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There is a continuous loud noise like water is rushing or gurgling in all pipes inside house for the duration when sprinklers run. Noise comes only if main valve for sprinkler line is half open.

Faulty valve or excessive pressure? Or do you have a different take on this? Regards, Tom

Tom, I think Poster should not hear water inside the house unless:

1. There is no pressure regulator installed
2. Sprinkler supply was tapped into house water ( was not taken directly from the main in front of the house ).

You are absolutely correct: most likely, there will be a faulty valve that generates the noise and transfers through the house...

Thank you for all of your responses.

It's a constant banging noise while sprinklers are on. Not like knocking which we also have a problem with when water running into washing machine and dishwasher turns off. It's only inside where the shut off valve and meter are located but it's loud enough that we hear it in the rooms above that area.

I don't see anything like the valve in the picture. Just the shut off near the water meter in our basement. I remember my bro-in-law saying he had to install a backflow valve but I thought that it was outside by the manifold.
Sprinkler guys redid manifold and buried it in underground box. I'll let you know when I get a pressure gage what the reading is.

The shut off valve I'm talking about is for the sprinklers.

Bro in law originally installed our sprinklers 14 years ago. Sprinkler contractor just replaced PVC manifold with copper piping. I asked him about noise and he said nothing could be done.

Also water pressure is decrease a lot everywhere in the house while the sprinklers are on.

I am having the same problem. We had sprinklers installed a few years ago and the noise has always been unbearable. We run them at 4 am because the water pressure drops when they're on. Our water meter is in our basement and that's where they put the valve to turn on the water supply for the sprinklers. I don't know what water pressure is. We have 3/4 inch copper pipes. Could that turn on valve be a backflow valve or is the one in picture the only kind? Is there any hope for peace in my house?

Water pressure 80psi
If we have the double check or backflow preventer and a pressure reducing valve installed will we still have the banging noise?

I had a plumber come today to give me a price on installing a backflow preventer and a pressure reducing valve. He said the my the pressure should be more like 55-60psi for the house and that the sprinkler system is fine at 80psi. I have a gas hot water heater. He said in addition to the 2 valves I need to have an expansion tank installed for the house plumbing and he also suggested a 2nd expansion tank for the sprinkler system plumbing. He said he can't guaranty this will totally get rid of the hammer problem (I also have the problem when the water stops running into my new washing machine and dishwasher) since the pipes may be loose in spots behind walls.

Can I get your thoughts on this please? I plan on having a couple of more estimates so I want to be sure I'm getting estimates for the correct work. Thank you.

Why isn't my question being answered instead of being combined with my old info?

For the same reason I'm merging this one! You don't start a new post any time you have something to say. You edit and add it to the original post

If the question is on the same situation,the moderators can combine the posts together as to not overlap information already given.

Posting a new question is for HAVING a new situation,not to update your situation.

Hope this clears it up a little for you:)

No it doesn't help. I guess this forum is not as helpful as I thought it would be. I'm asking for more advice on same problem because a plumber came to my house and I have no idea if what he's telling me is totally accurate. It's a matter of spending a few hundred based on what I was previously told or over a thousand dollars based on what this plumber told me. Thanks for nothing.

"A question well asked is half answered"

No one wants to go all over the board to find all of the information about your problem. What the plumber told you sounds quite logical. A thousand dollars does not.

First, you have gotten good help so far. Second, you've been told not to start a new thread, but to add to the existing thread. When you add a new response to a thread it DOES bump it on the new Activity listing.

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I guess this forum is not as helpful as I thought it would be.

Gee! It just breaks my heart that you're unhappy with us. (sob! )
Having said that let's get back to business shall we?

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I had a plumber come today to give me a price on installing a backflow preventer and a pressure reducing valve. He said the my the pressure should be more like 55-60psi for the house and that the sprinkler system is fine at 80psi. I have a gas hot water heater. He said in addition to the 2 valves I need to have an expansion tank installed for the house plumbing and he also suggested a 2nd expansion tank for the sprinkler system plumbing. He said he can't guaranty this will totally get rid of the hammer problem (I also have the problem when the water stops running into my new washing machine and dishwasher) since the pipes may be loose in spots behind walls.
Can I get your thoughts on this please?

I like the way this plumber thinks.
By all codes you should have a backflow preventer install on your water service and a PRV valve to reduce the pressure to a acceptable level. The expansion tanks are what I'd recommend to cushion the shock.
If you don't like the price get s few more estimates but follow the first plumbers advice.
Good luck, Tom