Leaking ABS to PVC fitting

Discussion in 'Plumbing Forum, Professional & DIY Advice, Tips & ' started by zimm0who0net, Nov 1, 2011.

  1. zimm0who0net

    zimm0who0net New Member

    Messages:
    17
    Location:
    Arizona
    So I just installed a bathtub and I've got a leak! The floor is slab on grade. I used some of that green PVC-ABS transition cement. Obviously I couldn't do the normal 1/4 turn when I dropped in the tub, so I just sort of crossed my fingers as I dropped the tub in and as it dropped in, guided the ABS tube into the PVC elbow.

    As you've probably guessed, when I filled the tub the next day, the damn thing leaked from that fitting. Not a huge leak, mind you, but enough to get some spots on a "witness paper towel" i folded around the joint when I drained the tub.

    So, now what do I do? I can't really move the tub at this point (set it in a bed of mortar and adhesived down the leveling feet). This is a crazy tight location. Part of me wants to say, "Heck, it's underground, just ignore it." but that part of me knows I'll always be thinking about it. I'm considering perhaps cutting the PVC tube that runs up to the overflow and trying to glob some cement over the inside of the joint, and then repairing the overflow tube with a Fernco.

    Help!

    Here's a picture of the situation
    IMG_0320s.jpg

    Here's a link to a larger version of the picture: http://i.imgur.com/milQ2.jpg
  2. Terry

    Terry Administrator Staff Member

    Messages:
    14,767
    Location:
    Bothell, Washington
    You could cut out the fitting and go with a banded coupling.
    Adding more solvent isn't likely to do anything for you.



    [​IMG]
    Last edited: Nov 1, 2011
  3. zimm0who0net

    zimm0who0net New Member

    Messages:
    17
    Location:
    Arizona
    You mean something like THIS?
    [​IMG]

    Will there be enough "meat" on the PVC pipes and the ABS pipe to make it into the coupling after I cut it out?

    EDIT: Also, does just leaving it leaking underground give you as much heartburn as it does me? My Father just told me to just cover it up. "A few drops of drain water in the Arizona soils (basically 100% sand) won't harm anything."
    Last edited by a moderator: Nov 1, 2011
  4. Tom Sawyer

    Tom Sawyer In the Trades

    Messages:
    3,052
    Location:
    Maine
    You can't glue ABS to PVC
  5. Jerome2877

    Jerome2877 In the Trades

    Messages:
    397
    Location:
    BC
    He used transition cement that is meant for joining the two materials however it may not be permited in some places by code. The real question is why not just use an abs waste and overflow in the first place?
  6. zimm0who0net

    zimm0who0net New Member

    Messages:
    17
    Location:
    Arizona
    I used Kohler K-7272 overflow drain which is the only drain that will work with this tub. It's all PVC. The overflow housing is PVC and is welded to the overflow downtube. The drain ell is PVC and is welded to the waste PVC tube. At some point I have to connect PVC to ABS. Not sure how else to do it other than I guess with a Fernco, but I'm very curious at this point!
    Last edited: Nov 1, 2011
  7. Terry

    Terry Administrator Staff Member

    Messages:
    14,767
    Location:
    Bothell, Washington
    [​IMG]

    We use a shielded coupling between the two materials.
    Proflex is one, or a no-hub coupling.
    This is a rubber coupling with metal wrapping around it to prevent the pipes from shifting out of position.
    If you use a rubber fitting without the support, wait a few years and find out that the fittings have sagged out of position and you no longer have a clear passageway for water.
  8. zimm0who0net

    zimm0who0net New Member

    Messages:
    17
    Location:
    Arizona
    Thanks Terry. I couldn't find a Tee version of the "shielded" coupler, only the non-shielded version. I cut out the old PVC fitting and put the new rubber T thingie in there. Seems I'm leak free for now. Do you think I'll have problems in the future because of the fittings "sagging out of position"?
    IMG_0322.jpg

    Also, why would Kohler create such a bath drain assembly out of PVC instead of ABS?

    EDIT: just saw that you edited my earlier post saying specifically that this is a BAD fitting for me to use. Hmmm. How about I pipe-clamp a few straps of steel around the sides of this thing to make it stay more straight?
    Last edited: Nov 1, 2011
  9. Terry

    Terry Administrator Staff Member

    Messages:
    14,767
    Location:
    Bothell, Washington
    A homeowner can use a non-supported fitting like that, because a plumbing inspector hasn't looked at it.
    A coupling can be made so that it doesn't shift; the pipe is rigid inside and then you wrap it with a metal band.

    What you have is a rubber fitting without any interior or exterior support. It may be fine over time, or it could shift.
    I've seen pipes after a few years that have dramatically shifted, those were lengths of pipe that caused one side to droop down.
  10. Winslow

    Winslow Plumber

    Messages:
    450
    Location:
    Hawaii
    You will be fine with thar repair. Don't lose any sleep over it.
  11. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,253
    Location:
    Cave Creek, Arizona
    Just remember, rubber ROTS and/or gets hard and cracks, therefore, you should make sure you can ALWAYS get to that fitting to replace it. There are several "good" ways you could have installed the drain. Using that "rubber tee" was not one of them.
  12. zimm0who0net

    zimm0who0net New Member

    Messages:
    17
    Location:
    Arizona
    Thanks everyone. I'll keep an access panel from the room next door.

    I am curious here about what the "right" way to do this would have been. hj, you mentioned that rubber rots, but I don't know of a way to connect my PVC tub drain to the ABS drain other than with rubber (which rots) or with transition cement (which apparently is against code and not a good idea regardless). Never a better time than right now to cut the whole she-bang out and do it the "right" way.
  13. Tom Sawyer

    Tom Sawyer In the Trades

    Messages:
    3,052
    Location:
    Maine
    Male and female adapters is the best way to go about this.
  14. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,253
    Location:
    Cave Creek, Arizona
    Transition cement is NOT bad, our gas utility used it to convert from ABS to PVC high pressure gas mains all the time. The problem is HOW you used it. But "transition couplings" would have been one of the proper ways to do it.
  15. zimm0who0net

    zimm0who0net New Member

    Messages:
    17
    Location:
    Arizona
    Thanks hj. Yeah, I certainly see that a better solution would have been to use a PVC tee and then a shielded transition coupling like Terry mentioned. However, aren't all the transition couplings rubber (that will crack over time, as you mentioned)?

    I really screwed the pooch on the transition cement for sure. The instructions said to assemble the drain, install the tub and the attach the drain to the trap. I dropped the tub in and tried to attach the drain at the same time because my trap was partially buried in some concrete so I didn't really have any play with what I was attaching to. That transition cement is not viscous at all. Not like PVC or ABS cement which is really goopy and probably would have bridged hairline gaps and sealed properly. Had I to do it over again I would not have assembled the PVC ell until after the tub was set, regardless of what the instructions actually told me.
  16. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,253
    Location:
    Cave Creek, Arizona
    The rubber in a shielded coupling is NOT exposed to the air, or the water, so it does not deteriorate.
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