Bubbles and slow draining kitchen sink

Discussion in 'Canadian Plumbing Code Questions' started by Inav, Jul 3, 2017.

  1. Inav

    Inav New Member

    Joined:
    Jul 3, 2017
    Location:
    Ontario
    Newbie here in Ontario.We renovating and due to new kitchen cabinets, we had to redo the plumbing under the sink.

    The venting stack is about 2 to 3 feet from sink drain.

    With the faucet fully open the sink slowly fills up and bubbles start coming up as it drains.

    We thought it was leaves in the vent stack on the roof. So flushed that with a garden hose. We noticed that when the garden hose is running in the vent stack, we do not have the bubbles in the sink.

    That seems to indicate that it is a venting issue. Seems like the "current" from the water coming down the venting stack is dragging the water from the sink with it. I guess the vent has a lower pressure with garden hose running in it???

    Looking at the P-trap, I think that the right side should have been higher by an inch or two. Btw, we are using 1.5" and. Will this fix the issue I am having?

    I have included a picture showing the current configuration.
     

    Attached Files:

  2. Reach4

    Reach4 Well-Known Member

    Joined:
    Sep 25, 2013
    Location:
    IL
    I would think that when you run the dishwasher, that would push up into the sink.

    I suspect a partial blockage where the drain line under the vent goes horizontal. That should have been a long sweep.

    If you redo, maybe feed the dishwasher into a tail piece meant to receive a dishwasher output. Put a long sweep on that vertical to horizontal if practical.

    Add a cleanout so that you could clean that elbow area.

    I don't know why no suds when you are running water down the vent.
     
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  4. Inav

    Inav New Member

    Joined:
    Jul 3, 2017
    Location:
    Ontario
    What do you mean by "Put a long sweep on that vertical to horizontal if practical"?

    In the picture attached, would that be #1 or #2?

    Don't you think that #2 should be higher than #1 by maybe 2"?

    Also by " bubbles", I mean air bubbles, not suds.
     

    Attached Files:

  5. Reach4

    Reach4 Well-Known Member

    Joined:
    Sep 25, 2013
    Location:
    IL
    #3.
     

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  6. Inav

    Inav New Member

    Joined:
    Jul 3, 2017
    Location:
    Ontario
    #3 is 2 pieces of 45 degree elbow followed by about 6" horizontal run into the verticsl drain. #10 is connected to the vertical stack.

    What should be the minimum horizontal run at #3?

    Also, do you think that the height of #1 and #2 are ok?
     
  7. Reach4

    Reach4 Well-Known Member

    Joined:
    Sep 25, 2013
    Location:
    IL
    OK. I mis-interpreted 3.

    I am not a plumber. I hope somebody has a good prescription for you.
     
  8. Highlander

    Highlander Member

    Joined:
    Dec 21, 2016
    Location:
    Ontario
    Possible blockages aside you have some s-trap/running-trap strangeness and the dishwasher is feeding into that backwards as well.

    Out of the sink #11 should go down directly into a vertical tailpiece where the dishwasher will also connect to, end of tailpiece goes right into one end of the p-trap, exit of p-trap then goes horizontally to the san-t #5 (add a 22 or 45 elbow as needed to get things to lineup).

    Connection at #10 and what it connects to could be suspect as well (is it a true vent or a stack that gets waste from, say, a bathroom above?).

    Adding a clean out fitting above #5 would be wise while you're in there reworking it.

    (not a plumber either)
     
  9. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Joined:
    Sep 2, 2004
    Occupation:
    Retired Systems engineer for defense industry.
    Location:
    New England
    My guess is that you wanted to maximize space under the sink, so you ran the drain back towards the wall before running it into the p-trap...not a great idea especially in a kitchen sink that can have food debris that might sit in that horizontal prior to the p-trap. It also slows the waste flow down. A straight shot to the p-trap, then run that outlet to the stack with the vent above, and it will probably work better.
     

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