I had a guy install a vent (black Portion in picture) under my two bowl kitchen sink but it does not seem to work when I have a full sink of water. When I go to let the water out, it just flows into the other sink bowl and drains very, very slowly. If I stick my finger in a small hole in the black vent, I feel a small rubber flap, and when I press down on it and allow for air, the sinks start draining. I have no clue whether it is installed correctly, at the right height, or what my problem could be. Does anyone have any suggestions? I am attaching a picture to show the plumbing set up...

And if you hold that rubber flap long enough water will come out. You are not letting air in, you are letting air out.

You have a blocked drain. Snake the line.

Once more "The Widget Maker" nailed it!
Harold's correct. You have a blockage located in the drain line.
Sponge the water out of the sink, remove the last "U" bend and snake from there. Good luck, tom

Hello Clyde,

The way it looks to me that you need to get rid of The S-Trap, see the drawing below, but wait until Tom, Mark, and Milo gets on and what will be their recommendation, Thank.

John

Johns layout's better but there's a problem. The drop through the floor looks to be directly under the continuous waste. There wouldn't be room for a San Tee and a AAV. I imagine that's the reason the AAV was off set. Regards. Tom

Thanks for the photo ! Excellent way of explaining your situation...

Sorry to say, but your pic shows incorrectly installed drain. You have two traps installed on top of each other. Afaroo has the solution to your problem. Do as he suggests and your sink will drain properly.

Milo,
Take another look at the picture. What he has is a "S" trap with a san tee downstream elbowing up to a AAv. I guess you could off set the AAV If you changed the configuration but you're correct, the vent should be repositioned. Regards, Tom

I would suggest having a different guy come in and redo the under sink drainage. Two things, the aav is not high enough to do you any good, and is also improperly piped. Afaroo has the correct drawing for correct install. You did say that if you push on the rubber flap in aav the sink drain just fine?? If so, this is strictly a venting problem, Should be sucking in air through the aav when sink is drianing. Try this, remove the aav completely, fill one side of the sink, then let it drain, while it draining, make sure to get under the sink and be ready to guickly screw back in the aav, in case water starts to over flow from aav fitting. If water overflows from this fitting, then Harold and Tom are correct, you have a partially plugged drain line. Please let us know how you make out. Lee.

Repiping of sink drain (tubular with aav in correct position) can easily be done by someone that knows what they are doing, and have the correct fittings. May take a 45 or two, but this should be an easy fix.

I'm not sure I am using this website correctly to answer all you guys. Thanks so much for all the directions. I had Roto Rooter snake my drain before this problem and they said they cleared anything that might have been in the pipes. I will have them come out again to eliminate that possibility and then I will get someone to look at the plumbing. I think it is a venting problem because normally my water drains fine. It is only when I fill one sink bowl and then try to let the water out. It backs up and fills both sinks. Ugh... I will let you guys know what works! Thanks so much for the help.

Tom, my suggestion is same as John's. Here is the visual... I would keep the AAV above all drains and as high possible...

Clyde123,

I agree with you that it is the vent problem and it can be checked very easy remove the AAV like Mygirlsdad says run the water for a while if the water runs good with no back up, then this defiantly the vent problem.

Then I will suggest to get red of the S-Trap and do your plumbing per Milo's or my drawing both are similar and you will be OK, Thanks.

Regards,
John

Hi all:

I popped in on this 'cause I noticed that almost everyone seems to be suggesting that the AAV needs to be run up as high as possible.

In fact, the AAV can be installed between 4" to 6" of the crown of the trap... see image. It can also be installed as high up as possible... just not required by AAV manufacturers... ;) In this case, with the STRAP in place, it should be moved a bit higher for sure.

If this was me, I would raise/replace the AAV first... may just be a defective AAV. If that didn't work, I would snake the drain. Finally, I would repipe this the NEXT time there is an issue under the sink... otherwise, I would leave it alone.

Just my input...

MARK

I think it's just easier for the water to run to the other sink than it is to get through the S trap. My suggestion would be to trap both sinks.

I like it Herald,
Great job of imaging. A skill I haven't mastered yet. Tom

Quote:

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Originally Posted by hkstroud

I think it's just easier for the water to run to the other sink than it is to get through the S trap. My suggestion would be to trap both sinks.

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He could also offset the line coming up through the bottom of the cabinet by cutting it as low as possible and then offset with 2 60's to the back of the cabinet, install a San-Tee on top of the 60's, install the AAV in the top of the San-Tee and then use a center outlet continuous waste and trap.

It's less than ideal, but it eliminates the S-Trap and eliminates the need to double trap the drain.

I like them all and it will work, Lee you have done a great job, Thanks.

John

Thank you John. Lee.