Should hot and cold pex pipes be separated? Or can they touch?

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by ironspider, Mar 5, 2010.

  1. ironspider

    ironspider Member

    Jul 26, 2008
    Greetings all,

    I am installing some pex-a piping and I've got several lines to run through a room about 30'. My plan is to run these pipes through a PVC conduit just to keep them neatly contained and organized.

    My question though is whether pex pipe must be kept in a state where the hot and cold don't touch? Or is pex constructed such that if a hot pex pipe was touching a cold pex pipe they wouldn't affect each other enough to be noticeable in any way at the fixtures?

    The reason I ask is because I'd like to run ONE pvc conduit through this space and attach it ot the ceiling with some hangers instead of TWO conduits.

    But obviously this is out if the pipes touching each other will have a negative impact.

    Thanks in advance!
  2. johnjh2o1

    johnjh2o1 Plumbing Contractor for 49 years

    Aug 9, 2009
    If they are touching each other for the better part of the run you could get a heat transfer from the hot to the cold.

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  4. nhmaster

    nhmaster Master Plumber

    Jul 30, 2008
    Tech. Instructor
    S. Maine
    By code they must be separated.
  5. hj

    hj Moderator & Master Plumber Staff Member

    Aug 31, 2004
    Cave Creek, Arizona
    If you want "warm" cold water, and "tepid" hot water run them together so they can affect each other. Otherwise separate them.
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