Air Chambers on a Moen Mixing Valve

Hi Folks...My first post. I am installing a Moen Posi-Temp L82680 shower control in a remodel and I need to know how and where to install the air chambers. I've never done it with a single mixing valve before. I think I would just install a vertical "T" fitting at the ends of the short pipes coming from the valve and install the supply lines to the bottom of the hot & cold T's and then rise the air chambers 12 inches from the top of the T's. Is this correct? The sooner I get an answer to this the better and I appreciate any help I can get. THANKS!!
Mike

The posi-temp doesn't need air chambers or hammer arrestors.
It's not a quick closing valve.

Quick closing valves are
dishwasher
icemaker
clothes washer

Most codes call for hammer arrestors, not air chambers.

If you use an air chamber on the valve, you can use tees.

I've used 3/4 x 1/2 x 1/2 tees, with a 18" 3/4" pipe and 3/4" cap.
It's not code anymore, but will work until it waterlogs, which is pretty quick.



What we did in the 70's but no longer done with the current batch of pressure balanced valves that are slow closing. A slow closing valve doesn't need hammer arrestors or air chambers.

WOW....an answer from the guru. THANKS, Terry!
UM....well...I have used air chambers (don't know what a hammer arrestor is??) throughout the house because they were used prior to my remodel. I hope that's ok because most of the house is drywalled. I guess, since you say that I don't need the chambers in my shower set up I will just leave them off and do without them. Hey...you're the boss. Wish I knew what hammer arrestors were. And I hope I haven't screwed up this remodel by trying to do everything right. BOY ... do I ever hope that!
Thanks again, Terry....thanks a LOT.
Mike

A hammer arrestor is a little chamber with either an air bladder or a piston in it...there is no direct air to water interface. With what you have, very shortly after you turn on the water, the air is disolved into the water, and they become useless.

Thanks, Jim....I ran into a plumber friend and he told me the same thing Terry told me about the items that need the arrestors. I put them in everywhere so far because they were there in the old installation. My friend told me that it wouldn't hurt anything...for which I am happy. Just more work for nothing.
Thanks again for the help......hey Jim....I'll see you again over at the John Bridge site.
Mike

I spend more time than I should on these two forums...

What? No time for Mike Holt?