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-   -   woud an air admittance valve help here? (

cephalopodian 05-20-2008 10:50 PM

Would an Air Admittance Valve help this problem?

i posted the following to Cragislist (chicago) today:

"I've got a washing machine draining into the P trap of a kitchen sink in an upstairs apartment. (connected by about a 10' run of heavy gauge hose). The machine is not fully draining on spin cycle.
The machine is still under warranty. I had a service guy out from the appliance company and he said there's nothing wrong with the machine, that the problem is how I've got the drainage set up.
I need someone who can help me figure out a better way to do this. I can probably (depending on what you advise) do the job myself -- I just need someone to tell me what to do...."

I got a bunch of responses indicating that the run was too long to be pushed through the hose, and that I'd need to run a pitched drainpipe line through the wall.

This is not what I wanted to hear for reasons of time, money, and mess...

But one guy suggested installing an air-admittance valve in the line:

"You need to vent the drain as sudsy water displaces air in the pipe.
You can vent the drain pipe by installing a "air admittance valve" or
punching a hole through the roof and venting it properly."

I'd never heard of an AAV before, so poked around Google, and learned a little about what the are...
But I don't really understand if/how it would help in this situation.

Does this guy know what he's talking about?
If he does, where should I put the valve (close to the machine, close to the P-Trap, or in the middle?)
If he doesn't, does anyone else have any ideas how this can be done without me needing to tear up walls to run pipe?


Alan 05-20-2008 11:57 PM

Actually, if i'm not mistaken, running a clotheswasher into a UTILITY sink is ok, but running it into a kitchen sink is a violation of code.

It sounds to me like your service man was right. Seems like there must be a reason they make those clotheswasher drain hoses so short. Your best bet is to actually put in a proper drain for your clotheswasher with its own trap, standpipe, and vent. Your other option is to move the clotheswasher close enough to the kitchen sink to use the factory hose on the clotheswasher, even though you shouldn't actually do that in the first place. Utility sink only.

Mike Swearingen 05-21-2008 05:00 AM

As stated, to do this properly would involve plumbing in a washer standpipe with trap and vent pipe. (I don't know why you aren't having clogging issues on a kitchen sink drain system with all of the washer lint that they put out.)
However, if you want to try an AAV, which I agree should help, you can plumb it into the hose near the washing machine.
You need to rig the AAV above a T with king nipples going out in both directions to go into both incoming and outgoing sides of the hose (clamp those with stainless steel hose clamps). This is just one way to do it.
Good luck!

8 Ball 05-21-2008 09:18 PM

An AAD does not compensate for poor plumbing. It simply allows you an alternate to venting thru the roof, provided you use one thats approved by your local plumbing codes, and installed instructions. Do the plumbing correctly, and avoid the property damages that you will be responsible for.

Dude think about it, youv spent a lot of money on a washing machine, but your still washing your underwear in the kitchen sink. Its not so funny after college.

Alan 05-22-2008 09:26 AM


Originally Posted by 8 Ball (Post 124928)
An AAD does not compensate for poor plumbing. It simply allows you an alternate to venting thru the roof, provided you use one thats approved by your local plumbing codes

Around here, they are illegal. :yes:

majakdragon 05-22-2008 10:04 AM

An AAV is not going to help in your situation. The run is too long. If it is a newer washing machine, the drainline should be 2" and not the traditional 1-1/2". Newer Plumbing codes are changing the size of washer drains because they pump the water at a faster rate than the older ones. Installation of an AAV is between the trap and the main drainline. It is meant to allow air into the sewage pipe to facilitate drainage and prevent the water in the trap from being sucked out.

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