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Pro Vent under the sink


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I inspected a remodeled 1917 home that had no vent for the sink drain, just a black device that is mounted horizontally. (I believe Air Admittance Valves are mounted vertically.) The markings are "pro vent AB8-1". I looked at the pro vent website, and see only one venting product, that is not even close to this device. Can anyone tell me more or guide me to a site with the information?


(whew! My first post)

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Regardless of who made it, it is not installed properly. It needs to be as high as possible under the sink to allow for proper operation. This also is tied to an "S" trap which is no longer legal. It also is not as water tight as it needs to be in that configuration. The springs and rubber closers are not meant for any substantial pressure, which could occur the way this is installed.

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Originally posted by tbird

I see those installed in kitchen island type applications in new homes. They are not just for manufactured homes. But, they need to be installed in an upright position.

There are two different designs. An air admittance valve is ok in a site-built home under the IRC (except in Oregon where they're outlawed).

The thing in the picture isn't an air admittance valve, it's a cheater valve (check vent) - a different design - that's made for use in a manufactured home. Cheater valves cost about $3.00. Air admittance valves cost about $30.00.

They both have to be installed vertically.

- Jim Katen, Oregon

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Never heard the term "check vent" before. After a quick stop at Google, the only pictures I could come up with look similar to an air admittance valve. Any more information Jim?

Next, I must be blind 'cause I don't see a check vent or air admittance valve. I see an S trap and what looks like a sanitary tee (I presume it goes off to a vent stack maybe?). It looks like the tail piece has some writing on it but I can't make it out. If the tail piece is the valve itself then they do need to be installed in the vertical. Also, they can't be buried behind a wall as they might need to be replaced/serviced in the future.

Thread drift alert::

Any freeware out there where you can right click on a picture and then zoom in?

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I did a lot of searching on the web, and found mostly that it is $4, and the only sites that sold them referred to Mfgd homes and RV.

One reader board mentioned that they were unreliable. They are a spring and rubber flapper. The flapper doesnt last long, and the spring breaks. Found no info regarding installation.

So, wrote up that:

1. unreliable

2. may be mounted in wrong orientation

3. may need to be higher than highest water level of sink.

4. call qualified plumber.

I would still like to find the installation instructions.

I will call the local code official soon and get their take.


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  • 3 years later...

Just to let you know while I was doing a google search for pro - vent I found the link to this post about half way down the first page.

It is the first time I have seen this type. it is yellow and said ABS on top of it. It is made to use in a mobile home.

Here are a few pictures.

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Terry, if you're using FireFox with a wheel mouse, hold down the Ctrl Key and roll the wheel forward or use Ctrl + to enlarge and Ctrl- to reduce.

In Internet Explorer, just use the percentage at the lower right corner to enlarge.


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