Little Help Routing Drains

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by winklebe, Oct 19, 2009.

  1. winklebe

    winklebe New Member

    Messages:
    10
    Location:
    Cleveland Ohio
    I am currently in the process of a master bath remodel, and I have a question regarding the venting / drains for the new double sink vanity that I plan on using. I will be moving the vanity to the opposite wall and building a lager shower in its place. On the new wall there was previously a toilet and one side of a corner tub. The toilet is being moved down the wall from the right side to the left side and the vanity will be on the right (all when looking at the wall).

    When I look at the existing plumbing, there is a drain that was used for the corner tub that I would like to use as the drain / vent line for the new double vanity. When I look at this set up I see that the vent pipe is offset to the left from where the center of the sinks will be. I am looking at my best option for plumbing the two drains to this existing stack.

    Please see the photo that I have attached for the 3 options I have been thinking of.

    1) To run two drain lines from the stack basically parallel (red Lines)
    2) To run a loop that spits the sinks and has a left and right branch (Blue Lines)
    3) Going in the room behind this wall and tearing up some more floor so that t can get to the lower portion of this drain (currently it is blocked by a Joist directly at the base of the wall that is hiding all of the lower components) once in the floor I will move the vent stack over to the right (green Lines)

    [​IMG]

    I am not sure what option is the best or if I missing something here (like the two drains have to enter the same fitting.

    Also if anyone has a comment as to the moving of the toilet you can see that in the photos as well. The stack goes up to the attic at the right and down to the sewer at the left end of the room. I was just going to move the Y fitting and the flange closer to the drain side.

    Thanks in advance. As I know I will have more question as time goes on (this is only the beginning)

    [​IMG]
  2. Doherty Plumbing

    Doherty Plumbing Journeyman & Gas Fitter

    Messages:
    810
    Location:
    Penticton, BC
    You are actually better off to to use one branch that picks up both fixture drains.

    IE something like this:

    [​IMG]

    The little green drawing is the top down view of the drainage. You can see that the 1st sink is picked up by a WYE not a tee. The end sink could be picked up by a 90 or two 45 degree bends.

    From where I am from this would be perfectly acceptable.
  3. dcelite

    dcelite Plumber

    Messages:
    132
    Location:
    Los Gatos, CA
    This is not acceptable in our area. You can not have two p-traps on the same trap arm and the second sink would become the vent for the first sink. We would use either the blue or the green piping system. I guess you'll have to check your local code.
  4. Doherty Plumbing

    Doherty Plumbing Journeyman & Gas Fitter

    Messages:
    810
    Location:
    Penticton, BC
    How about this?
    '
    [​IMG]
  5. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,267
    Location:
    Cave Creek, Arizona
    vent

    Still not acceptable here. The second sinks flow will be past the left hand sinks trap connection WITHOUT a vent. And the vent location shown in the second one is cosmetic, but does not perform any function. THe original drawing is correct, as long as the vent ties back 42" above the floor. Have no idea about the toilet because I do know if there are other factors that would prevent you from doing it.

    [​IMG]
    Last edited by a moderator: Jun 2, 2010
  6. winklebe

    winklebe New Member

    Messages:
    10
    Location:
    Cleveland Ohio
    HJ,

    Thanks for the input, One quick question. When you refer to the orriginal design are you refering to a situation where the drain is routed at the base over the the center of the two sinks then a vertical section is ran up and the two sinks are split off one to the right and one to the left then the verrtical is tied back to the orriginal vent (as the drawing in the beginning that is in Blue)??


    For the toilet what other items would you be concerned of? Its easier fro me to provided more information than to tear apart a faulty job because I was clueless.

    Thanks
  7. Doherty Plumbing

    Doherty Plumbing Journeyman & Gas Fitter

    Messages:
    810
    Location:
    Penticton, BC
    You guys don't allow for wet vents in your systems? I see my drawing as the far right sink wet venting the 2nd sink....
  8. dcelite

    dcelite Plumber

    Messages:
    132
    Location:
    Los Gatos, CA
    The wet vented section is horizontal (flat). Even a dry vent shouldn't be horizontal at that height.
  9. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,267
    Location:
    Cave Creek, Arizona
    drain

    Yes, the blue one. The right hand sink flowing past the left one's trap, can create a venturi effect and compromise the trap. It may NOT happen in real life, but we could cause it to happen in the testing laboratory. And IF it can happen there, then we assume it is possible to happen in the real world, which is why it is not allowed.
  10. GeronimoDF

    GeronimoDF New Member

    Messages:
    25
    Location:
    Long Island, NY
    So blue is the best option right?
  11. winklebe

    winklebe New Member

    Messages:
    10
    Location:
    Cleveland Ohio
    The blue routing from the original pic is what I have put together, I will post a pic or two tomorrow night after I put it in. Thanks again for all of the input all.
  12. Doherty Plumbing

    Doherty Plumbing Journeyman & Gas Fitter

    Messages:
    810
    Location:
    Penticton, BC
    Great thanks
    Last edited: Oct 22, 2009
  13. winklebe

    winklebe New Member

    Messages:
    10
    Location:
    Cleveland Ohio
    Ok all here are a few pics of the drain system that I have installed.

    You will notice I have also routed in an additional vent from the left for a toilet that was moved to that end of the room. As the toilet is connected to a 3" pipe that was running horizontal I was told that it was in fact a "Flat vent" and in case of a situation where the system backs up into the vent and clogs the primary vent (the 3" pipe) I needed to add a vertical vent.

    Let me know your thought and concerns as the wall is still open and I can make changes if something looks like it is not correct.

    As I am just an amateur at all of this your input is always greatly appreciated.

    [​IMG]

    [​IMG]

    [​IMG]
  14. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,267
    Location:
    Cave Creek, Arizona
    drain

    1. You used a sanitary cross instead of the proper fitting.
    2. You should ALWAYS have a cleanout either above or below the junction of the two lavatory drains, BUT you DEFINITELY need one when you use a cross.
  15. winklebe

    winklebe New Member

    Messages:
    10
    Location:
    Cleveland Ohio
    HJ,

    Thanks for the input, when you say the "Proper fitting", what would that be? Are you recommending a double Y fitting instead? If so what is the Benefit of the double Y vs. the risk of using the Sanitary?

    I have read that the only down fall to the sanitary cross is that a drain auger has a tendency to pass through the fitting instead of making the turn and heading down. If this is the basis of your concern then I will add a clean out just above the Junction and leave it exposed behind the vanity. (I am assuming this will just be a T with a Cap)

    I was of the understanding the as these are wet vents that a Y could lead the vent becoming broken when the water makes the turn as there is not enough air space at the top half of the fitting to allow the air to enter the pipe above the flowing water. (I hope this make sense).

    Let me know your thought.

    Thanks
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