AAV issues... doesn't seem to work.

[slanter]

So I picked up this "AAV kit" from home depot today to finally fix my sinks drain problem. My house is a converted garage (mother in law house sorta thing) and the pipes for the kitchen sink never had a roof vent put in, and since the whole place is made of cinder block, its rather hard to put one in so I decided to try a AAV.

its made by "Oatey" and its a "Sure-vent." I have two sinks, both drain to the same pipe, then go into a J-bend, then into straight pipe then down a metal pipe to the sewage. For years this sink would drain horribly slow, and a plumber told me it was because of the lack of venting. So I installed this AAV on the straight pipe between the J-bend and the sewer pipe with a T-fitting, turned on the sink, and checked it and nothing. same as before. I unscrewed the AAV, and as I unscrewed it I could hear the hiss of air rushing into the pipe as I was unscrewing the aav. So I tested the AAV by cupping my hand over the AAV, then putting my mouth to my hand and sucking in, and sure enough the valve opens with the slightest pull of air. So any ideas on why this thing doesn't want to work?

 

[slanter]

So i've tried a few other methods, tried extending the riser that the AAV is attached to another six inches, making it almost a foot tall and higher than the sinks themselves, still nothing, still nothing. Do you think the AAV is just faulty? I don't understand how it doesn't work when mounted on the pipe, even though theres a bunch of vacuum that I can FEEL and hear when I unscrew the AAV with water in the sink, but it works fine with I just try suck air through it. this is driving me insane!

 

[mogget]

The sink draining slowly implies air not being able to escape, as opposed to air not being able to get in (ie, vacuum)

An air admittance valve will help trap seal loss due to vacuum gurgling. It will do absolutely nothing to help a slow draining sink.

You need a vent somewhere on the system to let the air out. In the UK this is usually achieved through the use of a soil and vent pipe, I have no idea how it's done in the states.

 

[grndamgt4]

This is an old thread but I have the same problem as slanter and had come to the same conclusion about the air admittance valve not working right, I could feel and hear the air when I took off the AAV and the water would drain almost instantly while it was not attached. I had also extended it higher than the sink .

However, mogget was right, air was actually blowing out not sucking in.
I tested by taking the AAV off and putting a rubber glove over the hole held on by a rubber band. Filled up the sink and pulled the stopper, the rubber glove blew up like a balloon. Eventually when all the water had gone down, the rubber glove slowly went down and then was sucked into the pipe (which showed the AAV would still be needed to prevent water from being siphoned out of the trap).
I had snaked the drain several times with a 25ft snake in case there was a partial blockage preventing air from being pushed down the pipe fast enough but that did not help.

 

[bolshy]

Depends where you connected the AAV. It's not going to admit air until a slug of water draws a vacuum downstream of where it connects.