water hammer questions

[Kai]

Hi Everyone,

I really enjoy this forum. Thanks in advance.

I am re-plumping my house now. It is time to considering to install water hammer arrestor. I have few questions.

1. Which appliance should I install arrestor for?

2. If I install a arrestor at basement (the point to upstair bath), will it effective to help reduce shock on upstair bath (second floor)? Or should I put the arrestor under the counter of bathroom?

3. Should I install any arrestor on main pipe (3/4)? I split the 3/4 to 1/2 when it go into each appliance or upstair.


By the way, I am in CT.



Kai

 

[Clayton]

1. most important IMO would be the washing machine, dishwasher and Ref./Ice maker. (code in my area requires arrestors for every quick closing valve, which includes all single lever and 1/4 turn faucets.)

2. and 3. Find out what water hammer arresters are available in your area and read the manufacturers recommended installations.


I use Sioux Chief arresters. I generally install valve boxes with the built in AA size arresterr for the washer and ice maker. I also use the AA on isolated fixtures such as the kitchen or utility sinks. Then usually use the B size 3/4" arresters to cover one or two bathroom groups instead of installing individual arresters at each fixture. Each arrester should be installed as close as possible to the fixtures being served.

 

[Sponsor]

 

[Master Plumber Mark]

hammer arresters

install the pre built box at the laundry and the icemaker if you are really worried about this issue. I feel the icemaker is overkill, but they do make one that is not too expensive.


the best and most easy way to do the rest of the house is to just install a couple of long pipes going up behind the water heater 24 inches tall and put caps on them.

Technically that is an air arrester and it that works great. and really is all that is needed.

But if you absolutely feel the need , do the same thing at your tub and shower faucets too, jsut install a couple of tees and run some pipes up the wall a foot or two with caps on the end.

The same thing under the sinks too if you really want to beat a dead horse.

Its cheap , cheap, cheap and works forever, and it cant hurt.

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.

 

[Clayton]

Technically that is an air arrester and it that works great. and really is all that is needed.

Technically that is an air chamber and is not a recognized method of controlling water hammer shock, at least not in my area. Air chambers will not pass an inspection for use as a water hammer arrester here.
Text published by the international code council: "Note the distinction between water-hammer arrestors and simple air chambers. An air chamber, typically constructed of a capped section of vertical pipe, is ineffective in controlling water hammer. An air chamber located at the supply to every fixture was assumed to help control water hammer; however, air chambers become waterlogged in a short time. Air chambers allow a direct interface between the trapped air and the water, which allows the air to be absorbed or diplaced in a short period of time."