Back-to-back toilets -- how do I know whether I have cross or Y fitting?

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by sbcheli, Jun 12, 2013.

  1. sbcheli

    sbcheli New Member

    Lincoln, NE
    The guy finished grouting the new tile in our bathroom this morning. Tonight my husband went to install our new Champion toilet, and saw something in the instructions about needing a Y fitting if it was a back-to-back toilet. Now they tell us!

    I happened to take a picture of the torn-up floor before the tile was installed. Not knowing I'd need to see the toilet plumbing, I didn't get a good angle on the picture, but maybe an experienced plumber will be able to tell which fitting we have?

    I sincerely hope we don't have to rip up our new tile!!! Maybe we'll just have to return the toilet and get one with a less powerful flush. I was so looking forward to no more overflows!

    Please help. Photo attached. I can zoom in on it with Windows Live Photo Gallery, so I hope y'all can too. DSCF0501.jpg
  2. Terry

    Terry Administrator Staff Member

    Bothell, Washington
    I can't tell from that photo what fitting you have.
    A double fixture fitting will fairly well, a double santee isn't so good.
    Better is to have the wye fitting.

    Last edited: Oct 3, 2013
  3. hj

    hj Moderator & Master Plumber Staff Member

    Cave Creek, Arizona

    Your picture does not show the junction of the two toilets. That is where you should have the "back to back fixture fitting. A "sanitary cross" is ALWAYS a bad fitting although it will usually work without problems. A "double Y" can cause "siphonage" problems for the second toilet. Install the toilet and see how it works.
  4. Tom Sawyer

    Tom Sawyer In the Trades

    Since its not new construction I have to assume that the piping has been there for awhile and unless you have had problems in the past I wouldn't anticipate problems now.
  5. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    New England
    The older, higher flow toilets flush much slower than the new ones, so I'm not certain this is correct. The only way to tell is to install the new ones and bet is that it will have issues...the (highly) recommended fitting requires more space to install, and wasn't used much back when your house was built. The manufacturer's installation instructions put in the warning for a reason. If you do a search here, you'll find you are not alone...people do have problems updating their toilets when the proper back-to-back toilets do not have the proper fitting between them. It is not a problem if they are not back-to-back.
  6. Gary Swart

    Gary Swart In the Trades

    Yakima WA
    On the installation instructions for back to back Toto Drakes, it states the following: "Double sanitary tee-wye only, in vertical waste stacks..." There is a diagram showing that fitting, but I can not copy it. You can see the installation instructions by going to Toilet Reviewthen Shoppingthen Toto Toilets The key terms here are "Tee-Wye".
  7. Tom Sawyer

    Tom Sawyer In the Trades

    Perhaps one in several thousand. :)
    Having been at this for darn near 40 years now, and having done more back to back toilet installations over the decades then I can even begin to remember I'd bet there won't be any issues here either.
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