Water Hammer Arrestors

[jacksmith7]

I plumbed a bathroom in my basement and did not put in hammer arrestors. I've heard so much about how site-built arrestors (consisting of a length of copper with a cap on it at each faucet) become ineffective very quickly that I elected to leave them out.

If I have a hammering problem in the future, all the water lines are easily accessible from an unfinished part of the basement and I could add arrestors if I have to. I've plumbed several bathrooms without hammer arrestors and have not had a hammering problem. My question is, can there be damaging vibration of the pipes without there being an audible hammering noise?

 

[Jadnashua]

There are millions of homes built without any arrestors. The only time they are needed are for fast acting valves. A valve you manually close can cause loose pipes to bang, but the install has to be pretty poor.

 

[Sponsor]

 

[Got_Nailed]

Any arrester will fill with water if there is not a piston so if you do have a problem you’ll have to drain your lines so they will work again. This has been talked about a lot but there is a good pic of what I’m talking about on this post.

https://terrylove.com/forums/showthread.php?t=18603

 

[Seaneys]

There are millions of homes built without any arrestors. The only time they are needed are for fast acting valves. A valve you manually close can cause loose pipes to bang, but the install has to be pretty poor.

I'm using PEX near Chicago. My inspector has pretty much insisted that I have arresters. I can't argue with him (and really wouldn't want to), but this differs from what the manufacturers require.

I'd love know what brand you go with. I ended up using a brand available from a big box home store. I could not find a source for a professional grade arrester.

Steve

 

[Terry]

I use Sioux Chief, but I'm sure there are others that work fine too.

fixtures that you would expect to see arrestors on are,
Ice maker
Dishwasher
Clotheswasher

The one on the left is for a washer.
The one in the center can be soldered onto a tee.
The one on the right can be used inline like for a lav supply or an icemaker line.

 

[Slimjim43]

Terry,

I have a water hammer problem in my 3-unit complex.
I believe I know where the problem is. In the early morning,
when Unit A, shuts off water after taking shower, I can hear
a loud noise, it gives me a heart attack ever time I hear the sound. I already
installed Sioux Chief at the washer and the sound still exist. I plan
on installing Sioux Chief in Unit-A bathroom and kitchen at the Lav/Sink
that is attached to the water shut-off valve. I prefer this because I do
not need to shut-off the water for the whole complex. Do you think this
will resolve the issue I'm having? Or do you think I need to install it to the water line that is leading up to the shower, that means I need to turn water off to the whole complex and craw under the house.


Water pressure seems fine 50psi and I craw under the house last weekend, all pipes seem secured.

Thanks,
Eric

 

[Wrex]

The first step before installing any arrestors is to verify that the pipes are clamped to the joists properly.

I recently had this problem at my house in the basement it turns out all they used were those nail up (loop type) pipe hangers.

They do a good job securing the pipes to the ceiling to prevent them from falling down. However they don't hold the pipe from moving laterally and making those awful banging noises.

Whenever a faucet was turned off rapidly it was clearly obvious that the pipe was banging.

Using copper clamps screwed directly into the face of the joists solved the problem.

The noise you describe sounds like banging from improperly secured pipes.

Have someone quickly turn on the suspected faucet and turn it off rapidly while you observe the pipes.

If the noise you describe was as bad as mine you should observe some movement.

 

[Terry]

If you install the arrestor near the shower, say withing six feet on a lav or kitchen, it should help.

Normally, shutting off a shower wouldn't bang the pipes that much.
Is it something like the old Moen faucets that allow you to just shove it in to shut it off?

 

[Slimjim43]

I check all the pipes, they seem secure. I don't have banging in my pipes.
Just loud sound, like there is too much pressure in the pipes. My water pressure is fine 50psi. It only happens very early in the morning on cold days when unit A turns off shower.

 

[Wrex]

Then go with Terry's advice place 2 arrestors on the hot and cold line no more than 6 feet from the shower.

Note:

Don't buy the sweat on arrestors you will melt the O rings or destroy the piston when soldering if you don't do the soldering quickly and overheat them.

Buy the thread on arrestors then buy a female threaded T fitting Sweat X Female Thread X Sweat it has sweat connections on both ends and a threaded female fitting for the arrestor.

Like this:

http://www.pexsupply.com/img/categoryImages/Copper Copper Female Tee.jpg

The other way to make this T is to buy a standard Sweat X Sweat X Sweat T and solder a stub pipe onto it then solder a sweat to female fitting onto the stub pipe.

Since that requires more soldering and more time I recommend the fitting above so you only will have to solder 2 joints.

Don't forget to wrap the threaded male fitting on the arrestor with teflon tape and only tighten it until its snug no overtightening.