Adding fitting to existing drain

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by chukakid, Feb 24, 2009.

  1. chukakid

    chukakid New Member

    Messages:
    9
    Location:
    colorado
    Okay, you probably have answered this a million times but I couldn't locate what I needed to know so here goes. I'm going to finish my daughters basement and have run into a little problem. She wants a bar sink which unfortunately is not going to be on the same way as the bathroom so I have a problem with the waste line from the sink. There is a drain line from the kitchen sink that is close that I would like to tie into. The pipe is white PVC with a clean out just above the basement floor level. So I think I can add a 3x3x1 1/2 combo tee - wye as long as I get the drain line from the sink high enough. My question is how to I cut into an existing drain line and add a the new tee? I really don't want to redo the whole drain line. thanks:confused:
  2. nhmaster

    nhmaster Master Plumber

    Messages:
    3,189
    Location:
    S. Maine
    slip couplings, fernco's take your pick. Make sure you vent it.

    [​IMG]
    Last edited by a moderator: Feb 24, 2009
  3. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,815
    Location:
    Cave Creek, Arizona
    drain

    Back up a bit. Your SECOND problem is making the connection. Your FIRST one is that you cannot just connect to that pipe without making some provisions for venting, which you have not even considered.
  4. chukakid

    chukakid New Member

    Messages:
    9
    Location:
    colorado
    Adding to existing drain.

    Sorry should have included that fact. The house and the basement rough use the AAV valves for venting so I will tee off the sink drain with a new valve. Also, any recomendations on the heigth of the sink drain after the p-trap?
  5. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,815
    Location:
    Cave Creek, Arizona
    Aav

    An AAV will NOT work properly in this situation because it is a negative pressure vent, and your sink will be subjected to POSITIVE pressures which an AAV cannot handle.
  6. chukakid

    chukakid New Member

    Messages:
    9
    Location:
    colorado
    Oh oh, I was afraid of that. So since this sink is in the basement how could I vent it? I cant' get thru the upper floor.
  7. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,129
    Location:
    New England
    While you don't have to run a new line all the way to the roof, you do need to make the connection 6" above the flood plane of the highest drain served by the vent.
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