island vent

Discussion in 'Plumbing Forum, Professional & DIY Advice, Tips & ' started by data, Nov 28, 2007.

  1. data

    data New Member

    Messages:
    2
    The attached photo shows the island vent in my kitchen. It was taken during construction years ago. There is a small hole about 1/8 X 1/4 inch at the location marked "hole" in the PVC pipe. The hole was hidden in the 2-inch hole in the 2X4, which was discovered during remodeling. The pipe size is 2 inches. From what I read, this loop vent appears a bad vent and is likely not in compliance with the code. Is there a simple solution to improve the vent? I am thinking about replacing the loop vent with a Studor Mini Vent Air Admittance Valve by doing the following:

    Remove the two elbows and the pipe at the top. Seal off the pipe on the left at the top. Install a Studor Mini Vent AAV at the top of the pipe on the right.

    Is this better than the loop vent?

    Thanks for your help in advance.

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  2. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,618
    Location:
    Cave Creek, Arizona
    vent

    It is not better than a loop vent, and can cause misdiagnosis of a drain problem. What you have there is not a loop vent, it is someones own concept of a loop vent. If it worked then conditions were such that the drain would have worked even without the "loop", because it is completely ineffective.
  3. Cass

    Cass Plumber

    Messages:
    5,980
    Location:
    Ohio
    2 things.

    The loop vent should have a C/O on the other side.

    If you switch to an AAV I would check to see if it is code approved in your state and it will have to be exposed so it can be replaced, the T on the left will have to be changed to a Y. Or eliminate it and install a 90.

    Personaly I would change it to a Y and add a C/O above it
  4. Cass

    Cass Plumber

    Messages:
    5,980
    Location:
    Ohio
    hj is right the loop vent is wrong to begin with, the T on the left should not be there.

    They should both (left and right pipes) drop through the floor and connect in 2 different spots to the drain below.
  5. construct30

    construct30 New Member

    Messages:
    590
    Location:
    NorthWest PA
    Terry posted a really nice picture on the yet another island thread a day or so ago. An AAV is never a good idea unless all other options are out.
  6. data

    data New Member

    Messages:
    2
    Thank you very much, everyone, for your help. I found the picture that construct30 mentioned and saw what a proper island loop vent looks like. Since the basement is finished and the existing vents in the basement that go through the roof are far away and not in the nearest wall, it would be very time consuming to do a proper island vent. So I'll follow Cass' suggestions. The AAV will be installed in the wall with an access panel. By installing the AAV in the wall, it can be installed above the top of the sink.

    Thanks again for your help.
  7. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,618
    Location:
    Cave Creek, Arizona
    Aav

    Just remember with an AAV, if the sink does not drain, it may not be that sink drain that has the problem.
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