(206) 949-5683, Top Rated Plumber, Seattle
Page 2 of 2 FirstFirst 12
Results 16 to 17 of 17

Thread: Crown-Vented Laundry Drain Trap?

  1. #16
    In the Trades Tom Sawyer's Avatar
    Join Date
    Nov 2010
    Location
    Maine
    Posts
    2,938

    Default

    I turned the photo on it's side so that you could more clearly see the S configuration there. The 2x the pipe diameter from the weir to the inlet is what makes a P trap a P trap. Where the trap vents from is incidental. That trap in that configuration will siphon just fine with or without that vent. I have set that exact same thing up in the lab many many times using clear 2" PVC and fittings. given enough velocity (which a washer has) it siphons every time. Increase the weir to inlet by 2x pipe diameter or more and it never siphons. I can't think of a single plumbing code that will allow that configuration and again, there's not a plumbing inspector either state or local that would let that go around here including me.
    [B]No, plumbing ain't rocket science. Unlike rocket science, plumbing requires a license[B]

  2. #17
    Moderator & Master Plumber hj's Avatar
    Join Date
    Aug 2004
    Location
    Cave Creek, Arizona
    Posts
    25,632

    Default

    Thou dost protest too much. You are trying to justify the unjustifyible. You could not make that trap siphon even if you put a suction pump on the bottom of the drain riser. And that is how we tested traps and vents at the Chicago Cabrini Street Testing Laboratory. We did not just depend on gravity to create enough suction. And there are tens of thousands washer drains installed just like that and NONE fo them have "siphon problems", nor could they have them.
    Licensed residential and commercial plumber

Similar Threads

  1. Laundry drain pipe help for s-trap location. Canada
    By klrman in forum Canadian Plumbing Code Questions
    Replies: 11
    Last Post: 06-03-2010, 02:40 PM
  2. Laundry drain pipe help for s-trap location, Canada
    By klrman in forum Plumbing Forum, Professional & DIY Advice, Tips & Tricks
    Replies: 11
    Last Post: 06-03-2010, 02:40 PM
  3. Is this water closet drain vented properly?
    By mjsmith0 in forum Plumbing Forum, Professional & DIY Advice, Tips & Tricks
    Replies: 13
    Last Post: 02-15-2010, 02:51 AM
  4. is this drain adequately vented?
    By adrianmariano in forum Plumbing Forum, Professional & DIY Advice, Tips & Tricks
    Replies: 5
    Last Post: 02-01-2007, 05:41 AM
  5. Laundry Tub with No Visible Trap
    By sbaitso in forum Plumbing Forum, Professional & DIY Advice, Tips & Tricks
    Replies: 13
    Last Post: 06-05-2006, 10:07 AM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •