Sharkbite Water Hammer Arrestors

Water Hammer Arrestors

I have a question here to see if anyone has successfully used these Sharkbite Water hammer arrestors. I am contemplating trying one to try and fix an issue that has recently popped up. Was just wondering if these worked for anyone in solving the issue.

TIA

What is the issue that recently popped up besides the obvious. Details¿

Roughly a week ago, I started hearing sort of a 'pushback' or hammer noise coming from around the water heater. Noticed this everytime the dishwasher upstairs stopped the supply of hot water going into it. Thinking it was the dishwasher, I then tried the kitchen sink. When you abruptly shut off the water, and you are holding the hot supply line at the water tank, you can definitaly feel it, and hear it. You do not hear it at the sink/dishwasher area, but at the tank itself. If you slowly shut off the hot water at the sink, you do not get this type of action. I crawled under the house to see if the pipe was still connected (this is all in a farily tall crawlspace) and it appears to all be in fine shape. If I hold the line in the crawlspace while the water is abruptly stopped, I do not hear or feel it. I seem to only hear/feel it back at the hot water side of the tank. House was replumbed around 6 years ago with wirsbo/pex with crimp style fittings. Up to this point, everything had been hunky dory.

I did a little reading on here and did the whole turn off the water, open the hot/cold to drain the air/water out. I did this a couple of times and this didn't seem to make any difference. The cold water line doesn't seem to show this symptom, or at least it isn't apparent as much as the hot line.

I hope this is a decent explanation from a small brain like myself... Hope this helps. I was just hoping to cut in one of these arrestors on the 1/2" line before it enters the sink shutoff valve down in the crawlspace, or would a 3/4" one at the water tank make a difference?

hammer

Water hammer is caused by high velocity and rapid closure of a valve. If you piped the system with 1/2" PEX then you not only reduced the size of the pipes, but increased the flow velocity. An arrestor at the sink should at least minimize the shock. However, sometimes its effectiveness even depends on HOW it is installed at the sink. In other words, sometimes it makes a difference whether it is mounted to the end of a tee, rather than the center of the tee.

I guess I should have clarified. This is a leg that stretches out to our kitchen sink area. It is the longest run for the entire house, which when I trace it back to as far as I can see in the crawlspace, it comes from a 3/4" 'main' line. The house was done be a professional plumber when we had our house remodeled.

So it should be placed as close to the hot water stop (or right at the stop) for the faucet and dishwasher, as opposed to say 4-6 ft away in the easy access crawlspace?

arrestor

A shock arrestor is completely useless unless it is installed as close to the point causing the problem as possible. The term "as possible" meaning right at or within a foot, not 6' away.

Well, wen't a different route and installed a PPP arrestor with a 'T' at the faucet. This didn't correct the problem. I still get that hammer/air sound back at the hot water line of the tank. I did buy a hose bib style water pressure gauge and used it. It shows around 90psi. I checked it over at the neighbors as well and they were around 80-82.... I'm guessing that this is high, but I can't imagine that this would be causing the problem on the hot side outlet of the hot water tank...

Anyone have any thoughts here?

Dinger928 said:

Well, wen't a different route and installed a PPP arrestor with a 'T' at the faucet. This didn't correct the problem. I still get that hammer/air sound back at the hot water line of the tank. I did buy a hose bib style water pressure gauge and used it. It shows around 90psi. I checked it over at the neighbors as well and they were around 80-82.... I'm guessing that this is high, but I can't imagine that this would be causing the problem on the hot side outlet of the hot water tank...

Anyone have any thoughts here?

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90 PSI is WAY too high. There is no need to run your house @ 90 psi. 60 psi in my experience for a residential house is plenty.

1st step you need to take here is reduce your pressure by 1/3 and see how that goes. It's quite likely both yours and your neighbours PRV's have failed hehe.

And the pressure in the system when static is the same everywhere. This includes inside and outside of the hot water tank.

When our house was replumbed, I'm doubting there was even a PRV installed. If there is one out there, I have never seen it. Where do these get installed? At the street? I know our main water shutoff valve doesn't have one anywhere near it.... Is it worth calling the water department and ask what the static pressure should be for my neighborhood?

Dinger928 said:

When our house was replumbed, I'm doubting there was even a PRV installed. If there is one out there, I have never seen it. Where do these get installed? At the street? I know our main water shutoff valve doesn't have one anywhere near it.... Is it worth calling the water department and ask what the static pressure should be for my neighborhood?

Click to expand...

It depends on your situation.

Usually in new homes they are installed by the main shut off as soon as the water enters the house.

Some older places are out on the street. But maybe in your area all of them are out on the street.

It's not usually common to have a communal PRV but they are out there in some high density areas.

But if you call the water department they should beable to tell you if you need to supply your own or if they have one out at the street etc etc.

If you do install a PRV you will also need to install a expansion tank at the same time...

Ok, had the water department out today while I was at work. They did a water pressure test and recorded 80psi. They left the door hanger on the door with a note commenting on whether or not I had a PRV installed or not. So that tells me that they did not see one at the street.

Hrm, this problem is driving me nuts, the wife can live with it, now curiosity is making this my obsession....

Dinger928 said:

Ok, had the water department out today while I was at work. They did a water pressure test and recorded 80psi. They left the door hanger on the door with a note commenting on whether or not I had a PRV installed or not. So that tells me that they did not see one at the street.

Hrm, this problem is driving me nuts, the wife can live with it, now curiosity is making this my obsession....

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Well then it's obvious you don't have a PRV installed!!

Get a PRV installed.

I believe in your code you guys need an expansion tank installed between the discharge of the PRV and the cold inlet of the tank, with NO valves installed in between.

This should fix your problem.

Wow, that sounds like a foreign language to me there!

I believe in your code you guys need an expansion tank installed between the discharge of the PRV and the cold inlet of the tank, with NO valves installed in between.

This should fix your problem.

Doherty Plumbing said:

Well then it's obvious you don't have a PRV installed!!

Get a PRV installed.

I believe in your code you guys need an expansion tank installed between the discharge of the PRV and the cold inlet of the tank, with NO valves installed in between.

This should fix your problem.

Click to expand...

Correction...You should have valves between the PRV and tank...Many times they are placed right after the PRV and above the expansion tank also to make future changes easy.