(206) 949-5683, Top Rated Plumber, Seattle
Results 1 to 3 of 3

Thread: sealing unions?

  1. #1
    DIY Junior Member hmarkn's Avatar
    Join Date
    Jan 2012
    Location
    British Columbia
    Posts
    1

    Default sealing unions?

    Hi:

    I was wondering if any more experienced plumbers can assist me with this. I recently witnessed a company that was applying teflon tape and pipe dope to a brass union on an antiscald valve for a bath tub. In my experience (I have only been plumbing for less than 5 years) with brass unions such as those on a pressure reducing valve, the rubber (or fibre) gasket was sufficient for sealing it. Am I correct in thinking that the small rubber gasket with built in strainer on these unions is sufficient for the seal, and that the tape and dope is not necessary? Or am I wrong. As I said, I have only been plumbing for a few years and welcome any more experienced feedback. Also, I am plumbing in Canada so not sure if any Canadian plumbers can correct me if the code here says otherwise. I don't remember reading it but I haven't received all the updates since I got my ticket.

    Thanks.

  2. #2
    Retired Defense Industry Engineer jadnashua's Avatar
    Join Date
    Sep 2004
    Location
    New England
    Posts
    21,399

    Default

    The only time you need to seal the pipe joint with pipe dope or tape is on a tapered pipe thread. Any other connection is sealed with some sort of gasket (like a hose on a hose bib). It doesn't hurt to put a little pipe dope on the mating surface of a union, but tape will often create a leak.
    Jim DeBruycker
    Important note - I'm not a pro
    Retired Defense Industry Engineer; Schluter 2.5-day Workshop Completed 2013, 2014

  3. #3
    Moderator & Master Plumber hj's Avatar
    Join Date
    Aug 2004
    Location
    Cave Creek, Arizona
    Posts
    25,633

    Default

    Putting tape or compound on a gasketed joint does absolutely NOTHING to help it seal. Compound on a ground joint union help seal any small imperfections which could cause leaks.
    Licensed residential and commercial plumber

Similar Threads

  1. unions and pex
    By ginahoy in forum Water Heater Forum, Tanks
    Replies: 1
    Last Post: 09-12-2009, 05:08 PM
  2. Brass Unions
    By BimmerRacer in forum Plumbing Forum, Professional & DIY Advice, Tips & Tricks
    Replies: 6
    Last Post: 08-21-2009, 01:13 PM
  3. Unions. Yes or NO?
    By Master Plumber 101 in forum Plumbing Forum, Professional & DIY Advice, Tips & Tricks
    Replies: 297
    Last Post: 06-25-2009, 10:21 PM
  4. Water heaters and unions
    By Agu in forum Plumbing Forum, Professional & DIY Advice, Tips & Tricks
    Replies: 7
    Last Post: 06-22-2009, 08:00 AM
  5. Using Unions
    By BimmerRacer in forum Plumbing Forum, Professional & DIY Advice, Tips & Tricks
    Replies: 5
    Last Post: 04-22-2009, 02:06 PM

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
  •