Leak at P-trap/drain connection with new kitchen sink

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by jmaland, Feb 27, 2007.

  1. jmaland

    jmaland New Member

    Messages:
    9
    Hi,

    My issue is that I installed a new sink that is deeper than the previous sink, where my output pipe from the garbage disposal is slightly lower (almost an inch) than the drain out thru the wall.

    I tried to add an extension between the drain out and the J-pipe connection, but had a single leak at the point where I hacksawed the extension pipe to get it right at where the J-pipe connected to it. I've never messed with plumbing before, but I'm thinking you can't just add a movable washer to the end of a sawed off pipe for the tip of the J-pipe connection.

    I've only gone to Home Depot for parts, so I'm hoping that maybe a specialty plumbing store will have an expanded parts section.

    My exact measurements with this problem are:

    - drain out to floor distance: 16 & 1/2 inches
    - garbage disposal output to floor distance: 15 & 1/4 inches
    - drain out to garbage disposal output distance: ~6 inches

    Any advice would be great.

    Thanks,

    Jim
  2. coz

    coz New Member

    Messages:
    91
    Location:
    MA
    if your sinks lower you would have to cut down the 90 that comes out of the disposal and shorten your tailpiece if you have a double bowl. i dont understand what you are extending
  3. TedL

    TedL New Member

    Messages:
    604
    Location:
    NY Capital District
    Stuff does not flow uphill. You need to lower the inlet at the wall, raise the sink, or lose the disposal.
  4. coz

    coz New Member

    Messages:
    91
    Location:
    MA
    he may be able to build a slightly larger trap to make up the diff
  5. coz

    coz New Member

    Messages:
    91
    Location:
    MA
    is it a single bowl sink?
  6. jmaland

    jmaland New Member

    Messages:
    9
    It's a deep single bowl with a garbage disposal, where the outlet straight out of the garbage disposal is an inch lower than the drain out thru the wall.

    It does seem funny to think that the water should flow uphill by an inch, but I was hoping that by the nature of the p-trap (to keep water blocked between the sewer and your sink drain) that the less than an inch differential wouldn't matter that much.

    Other people must have similar problems like this, right? Or am I the only guy who lets the wife pick out an sink without measuring the drain outlet?

    Is my only course of action to move the drain in the wal down by an inch or two?

    Thanks,
    jim
  7. coz

    coz New Member

    Messages:
    91
    Location:
    MA
    use a regular 90 into the trap instead of the street 90. you can add a small piece of pipe inbetween giving your trap an extra inch.
  8. markts30

    markts30 Commercial Plumber

    Messages:
    630
    Location:
    Phoenix, AZ
    I would think the best bet would be to cut into the wall and lower the drain to make this piping work...
  9. TedL

    TedL New Member

    Messages:
    604
    Location:
    NY Capital District
    Larger in what dimension? Making the trap larger vertically would only drive the outlet further away from where it needs to be. And larger horizontally wouldn't change the height.
  10. jmaland

    jmaland New Member

    Messages:
    9
    The problem with moving the drain is that it's encased in a brick wall (which seems like it would be a huge pain to break into to move it down only an inch).

    Our other option of not having a garbage disposal seems easiest to fix the problem, but not a good thing to do (with the dishwasher we just added).

    I think I'm starting the consider replacing the sink I installed with a slightly shallower sink. The wife already found a similar one that is an inch less deep than the one I put in already (which is all I need to get the garbage disposal output lined up with the drain). Are there any problems with have a straight output from the garbage disposal into a p-trap?

    Or I just bridge the pipe gap and have some water always sit at the bottom of the garbage disposal. I know this isn't optimal, but would this cause major problems with the functioning of the garbage disposal over time?

    Thanks for the help everyone,

    Jim
  11. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,143
    Location:
    New England
    The outlet of the P-trap to the wall should slope down at 1/4"/foot. Sounds like the shallower sink is the best option here.
  12. TedL

    TedL New Member

    Messages:
    604
    Location:
    NY Capital District
    It is especially problematic to try to get solid stuff to flow uphill, and sending solids down (up?) the drain is the modus operandi of a disposal.

    You have solid brick between the sink base cabinet and the pipe?
  13. markts30

    markts30 Commercial Plumber

    Messages:
    630
    Location:
    Phoenix, AZ
    If the drain line is in a brick wall and you don't want to go to the trouble of moving it down a couple inches, go with the shallower sink...
    Make sure the disposal outlet is slightly higher (1/2" or so) that the drain inlet at the wall to allow for fall..
  14. jmaland

    jmaland New Member

    Messages:
    9
    Hey, just a follow up on what I did to solve my problem ...

    I got a sink 2 inches shallower and everything fits great now (had to use one of those flex-end p-trap for the bend from the garbage disposal into the Jpipe though, since no a lot of spare room).

    We've been running water and garbage thru it for a few days now and everything seems fine.

    Thanks to eveyone for helping me realize that the p-trap wasn't a magical device that would puch water up an inch ...

    Jim
  15. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,831
    Location:
    Cave Creek, Arizona
    P trap

    It sounds like you did it almost right. That flex P trap is bad news.
  16. jmaland

    jmaland New Member

    Messages:
    9
    Why is the flex p-trap a bad thing to use? Is it not up to code? Does it get clogged easily? Leak, break, ...? I tried googling around and could not find any info on the subject.

    I first tried the fit using the 90 deg bend pipe that came with the garbage disposal, but it looked like the regular p-trap Jpipe would have been a hair off (eighth inch) of the drainage output pipe, so rather risk a leak by forcing it together I grabbed the flex ptrap and it fit great with a pipe straight out of the garbage disposal instead.

    If this really is a big issue (using the flex ptrap or forcing it together with a regular ptrap), my backup plan is to get a compact garbage disposal that will add an additional half inch to the connection and solve this problem. Is this really necessary though?

    Any advice would be great ... thanks

    Jim
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