back to back toilets

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by se215, Jul 3, 2008.

  1. se215

    se215 New Member

    Messages:
    9
    do you think there will there be any venting or vacuum problems
    if the 2 toilets are installed back to back with a double combo wye
    with one 4" vent
    (the code in philadelphia allows us to pipe the other toilet in without
    an additional vent as long as it is within 8' from a vented line)

    should i use a double combo wye or a double san tee?

    Attached Files:

  2. kordts

    kordts In the Trades

    Messages:
    551
    Location:
    exurban Chicago
    If it's horizontal it has to be wyes.
  3. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,235
    Location:
    Cave Creek, Arizona
    toilets

    It is allowed EVERYWHERE not just Philadelphia, but in some cases it has to be a double fixture fitting, not a double combo which is similar but different. The tub and lavatory, however, are no where near correct as drawn.
  4. se215

    se215 New Member

    Messages:
    9
    philadelphia has its own plumbing code
    i thought the IPC would require an additional vent for the toilet
    on the right side

    the tub and lav lines are connected to a 4" ideal bend with (2) 1 1/2 taps
    which is legal in philly as long as it is within 48" from the stack
  5. se215

    se215 New Member

    Messages:
    9
    double fixture fitting?
    is that a double san tee

    Attached Files:

  6. you have the wrong fitting...

    what you need is a double tee like you have but
    with 2 inch side outlets

    it is called an Double Ideal Cross ans we used to use hundreds of them for this actal application.

    you tie in the fixtures into the two side outlest on the double tee and it basically is vented by the stack...

    teh pvc fitting I am talking about costs about 20 bucks


    I have a bunch of them sitting in mothballs....

    this is about the best pic I could find of a sanitqary tee with a side outlet

    now just immagine it in a cross tee with two side outlets.....


    [​IMG]
    Last edited: Jul 4, 2008
  7. jimbo

    jimbo Plumber

    Messages:
    8,997
    Location:
    San Diego
    I guess I have a question.....in the drawing, is the main drain actually vertical, as shown, or is that an overhead view of a horizontal drain ??
  8. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,235
    Location:
    Cave Creek, Arizona
    fitting

    double fixture fitting?
    is that a double san tee

    No. A double fixture fitting is similar to a double combo. However, since the branches are connected at a 60 degree angle instead of the combo's 45 degrees, it creates a shorter fitting between the two branch hubs, and also connects to the riser sooner eliminating the creation of an "S" trap configuration, which is caused by using a double combo.
  9. hj, I dont know what it is called

    I dont really know the real name for a
    double cross with two side outlets....


    It used to be called a
    "double cross ideal tee with two side outlets "
    by men of "true grit" when I was 13 years old....
    and we installed thousands of them......

    they still pass code here, and were UPC approved way back in the 60s,

    I still got some of those ideal crosses made out of brass that date back to when
    men were really men and soldered them together in crawl spaces...


    but wether they would apply well to the drawings this fellow left here is anybodys guess....

    I should jump in my car right now and go take a picture of
    one of them but the gas is too high to do that today

    maybe tomorrow when I got to go down there.......


    HJ... I know just you cant wait to see them....
    Last edited: Jul 4, 2008
  10. se215

    se215 New Member

    Messages:
    9
    the main drain is the horizontal pipe
    the 4" stack is vertical (the bathrooms are on the second floor)
  11. se215

    se215 New Member

    Messages:
    9
    the bathroom group on the left is exsisting (i am not worried about the tub and lav drain lines,they are tyed into a 4" cast iron ideal bend,which is legal here in philly)
    i am trying to add the toilet on the right side
    i just was not sure if i should use a double combo wye or a double san tee

    thank you for all your answers so far
  12. it depends

    of course a combo wye would be better ,
    but the combo tee would work ok too...

    it really depends on how much room
    you have to work with...

    if you have a drop ceiling underneath this mess
    , with plenty of room to play with.

    you will have it easy ,
  13. se215

    se215 New Member

    Messages:
    9
    do you think there will be any problems with trying to
    snake the drain with a double san tee
  14. once in a million....

    their wont be a problem because the odds are
    you will never have to snake a drain that size on
    a second floor in the first place....

    of course a double wye would make a snake work better
    but you are talking about some very high odds here.....

    we literally installed thousands of them
    without a single complaint in well over 40 years

    if that actually were to ever happen,
    if somehow some sort of GI joe toy were
    to make it through the toilet and down
    into the stack and lodge in that cross........
    it would be like a 10 millon to one chance.....

    If it did ever happen , I suggest you go out
    and buy yourself some lottery tickets,
    Last edited: Jul 5, 2008
  15. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,235
    Location:
    Cave Creek, Arizona
    tee

    IF you had to snake through a sanitary cross, you would have one big problem, namely that you could not do it, at least unless you were very, very lucky. That is why they make back to back fixture fittings. It is also the reason few codes allow the sanitary cross for that purpose.
  16. se215

    se215 New Member

    Messages:
    9
    what about a drop head auger?
    that would not work
  17. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,235
    Location:
    Cave Creek, Arizona
    snake

    The only drop head augers I have ever seen were on snakes which were to small for a 3" or 4" stack. The proper snakes are too stiff to turn down the center stack. In fact because they are stiff, they prefer to make a complete 180 turn and go up the stack, rather than perform an "S" turn and go down it. These comments, of course, refer to a sanitary cross, not a double fixture fitting which eliminates this problem.
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