(206) 949-5683, Top Rated Plumber, Seattle
Results 1 to 4 of 4

Thread: WC Hammer - can't fix this

  1. #1
    DIY Junior Member mystreba's Avatar
    Join Date
    Mar 2008
    Location
    highland, md
    Posts
    16

    Default WC Hammer - can't fix this

    Break it down...

    I recently installed a WC/Urinal combo in my bath. Fixtures, plumbing and flushometers are all brand new.

    Name:  IMG_2622.JPG
Views: 106
Size:  81.6 KB

    I ran a dedicated 1" supply line directly from my 86-Gal, 40/60 pressure tank to feed these two fixtures. A reducing sleeve in the 1" tee right between the two fixtures sends 3/4" supply over to the urinal. All supply lines are held very securely to the framing with clamps. Supply lines are CPVC all the way to the flushometers.

    WC has a Sloan 136 1.5' top spud flushometer (yes, it's the squat toilet model but the tech at Sloan informed me it was the same as the 110 model except the vacuum breaker tube is longer and just required cutting to size). Urinal has a Kohler K-13519 3/4" top spud flushometer.


    Kohler urinal flushometer works great.

    When I installed and adjusted the Sloan WC flushometer, it worked well for 3-4 flushes. Then the supply line began hammering violently behind the wall. I closed off the stop valve, pulled the piston and re-installed it. Once again, after initial adjustment the flushometer worked well for 3-4 flushes, then the supply line began hammering violently behind the wall. I verified that the piston is correctly sized for the 1.6 GPF Kohler WC. The troubleshooting guide in the installation instructions says "the size of the orifice in the 'bypass' is critical for proper metering of water". Unfortunately they don't bother to indicate what/where said "bypass" is.

    Sometimes the hammering settles into a rhythmic knocking - you can hear the vacuum trying to seal. The knocking won't stop until I also flush the urinal.

    I've adjusted until I'm blue in the face - any thoughts on how to stop the hammering?

    many thanks

  2. #2
    Retired Defense Industry Engineer jadnashua's Avatar
    Join Date
    Sep 2004
    Location
    New England
    Posts
    21,374

    Default

    You may need to install hammer arresters on the lines.
    Jim DeBruycker
    Important note - I'm not a pro
    Retired Defense Industry Engineer; Schluter 2.5-day Workshop Completed 2013, 2014

  3. #3
    DIY Junior Member mystreba's Avatar
    Join Date
    Mar 2008
    Location
    highland, md
    Posts
    16

    Default

    Quote Originally Posted by jadnashua View Post
    You may need to install hammer arresters on the lines.
    Thanks, will do. I can't say it will be an easy job, access-wise. Some questions first:

    1 - Any advice on placement before I get in there and start cutting? See diagram below. Should I put one on each line after the tee or put only one before the tee?
    2 - What type arrestor is recommended for this 1" CPVC installation - air/diaphragm or gas/piston?
    3 - Should it be sized to the pipe or can I install the more common 1/2" arrestor?

    Name:  pipes 2.jpg
Views: 72
Size:  17.7 KB
    Last edited by mystreba; 04-08-2013 at 09:01 AM.

  4. #4
    Retired Defense Industry Engineer jadnashua's Avatar
    Join Date
    Sep 2004
    Location
    New England
    Posts
    21,374

    Default

    Functionally, you want the arrestor to be close to the valve so the moving water column has somewhere to go without there being a lot of water left to bang on the valve. But, you may find that the piping is just not anchored well. Still, if it is moving, you want both anchors and the arrestor. I don't have much long-term experience with them...the ones I have are piston type, but they aren't super old. They work. I think you'd find it needs to be sized for the water line and valve you are using otherwise, it may just bottom out and not be able to perform its function...best to see what one of the pros has to say. Some research on the supplier's website and spec sheets may resolve the question.
    Jim DeBruycker
    Important note - I'm not a pro
    Retired Defense Industry Engineer; Schluter 2.5-day Workshop Completed 2013, 2014

Similar Threads

  1. Water Hammer & Water Hammer Arrester location
    By amkazen in forum Plumbing Forum, Professional & DIY Advice, Tips & Tricks
    Replies: 13
    Last Post: 09-10-2013, 09:26 PM
  2. getting rid of hammer
    By v1rtu0s1ty in forum Irrigation / Sprinkler Forum
    Replies: 6
    Last Post: 08-26-2009, 10:50 AM
  3. Water Hammer
    By rockycmt in forum Plumbing Forum, Professional & DIY Advice, Tips & Tricks
    Replies: 1
    Last Post: 02-01-2008, 10:31 AM
  4. Demo Hammer/Roto Hammer--Help me choose
    By rshackleford in forum Plumbing Forum, Professional & DIY Advice, Tips & Tricks
    Replies: 17
    Last Post: 07-03-2007, 05:34 PM
  5. Hammer Arrestors
    By NaplesX5 in forum Remodel Forum & Blog
    Replies: 2
    Last Post: 08-04-2006, 08:25 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
  •