Hard seat and soft seat

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by dx, Oct 22, 2010.

  1. dx

    dx General Contractor

    Messages:
    156
    Location:
    Michigan
    Last edited: Oct 22, 2010
  2. jimbo

    jimbo Plumber

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    8,997
    Location:
    San Diego
    Hard seat means metal to metal contact. A soft seat would have a seating surface with a rubber gasket, or maybe a teflon ring, or such.
  3. hj

    hj Moderator & Master Plumber Staff Member

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    When it comes to check valves, a soft seat will not make as much noise when it closes. The hard metal to metal contact of the hard seat can cause be quite loud, especially if there is a lot of back pressure "slamming " it shut. The hard contact can also cause it to "rebound" creating a chattering noise.
  4. dx

    dx General Contractor

    Messages:
    156
    Location:
    Michigan
    Thanks guys. Related question: some swing checks are labeled "for horizontal installation only". I do understand why. But why aren't all of them labeled that way? Can some of them be installed vertical or is it just that some manufacturers fail to label them properly?
  5. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,811
    Location:
    Cave Creek, Arizona
    I cannot imagine why they would be labled that way, since gravity and the weight of the liquid would close them in a vertical orientation. When they are installed horizontally, some have a label to show which side should be on top, because the hinge location is not obvious.
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