Reducing 2” to 1 1/2” kitchen pipe

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by Akadb, Jun 26, 2020.

  1. Akadb

    Akadb New Member

    Joined:
    Jun 26, 2020
    Location:
    Ohio
    I am a complete beginner so please forgive my ignorance. I am replacing the kitchen sink and disposal in a house I’m renovating and as I was removing the old ones I realized the pipes are 2” instead of the 1 1/2” I was expecting. Is there a reducer that will fit the end of the tailpiece coming out of the wall to transition to a 1 1/2” J-trap? I could not find anything at the local home improvement stores or any information online about those specific sizes. If not, what else can I do here? Should also add that I’m moving from a double basin sink to single basin.
     

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  2. Terry

    Terry Administrator Staff Member

    Joined:
    Aug 17, 2004
    Occupation:
    Plumber
    Location:
    Bothell, Washington
    1.5" pipe that is ABS or PVC is about 2" on the outside diameter.
    The p-trap below is a standard 1.5" tubular trap that fits into a trap adapter that glues onto the pipe from the wall and fits inside sealing with the slip joint washer and nut.

    [​IMG]
     
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  4. Sylvan

    Sylvan Still learning

    Joined:
    Sep 23, 2004
    Occupation:
    plumbing - fire suppression - boiler inspector
    Location:
    New York
    If your using a disposal I would use a 2 x 1 1/2 P trap not reduce the size of the traps outlet
     
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  5. Terry

    Terry Administrator Staff Member

    Joined:
    Aug 17, 2004
    Occupation:
    Plumber
    Location:
    Bothell, Washington
    If the disposer is less than eight years old, the blades are still sharp enough to make small little chips.
    After eight years, things get dull and you wind up with big problems downstream when the size of the chips get much larger. Ten years is the max age for a disposer if you want it to actually work like it's supposed to. They may spin, but they also need to chip that stuff into little bits for you too.
     
  6. wwhitney

    wwhitney Well-Known Member

    Joined:
    Mar 17, 2019
    Location:
    Berkeley, CA
    How does that sort of trap comply with, e.g. UPC 1003.3, which says in part "The trap shall be the same size as the trap arm to which it is connected." Is it considered a 2" trap with a 1-1/2" inlet?

    Cheers, Wayne
     
  7. Reach4

    Reach4 Well-Known Member

    Joined:
    Sep 25, 2013
    Location:
    IL
    I don't think IPC has that. It says
    1002.5 Size of fixture traps. Fixture trap size shall be sufficient to drain the fixture rapidly and not less than the size indicated in Table 709.1. A trap shall not be larger than the drainage pipe into which the trap discharges.​
    Maybe there is somewhere else that speaks to the trap arm and the trap being the same size, but I did not find it.
     
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