Water hammer after pressure balance valve install

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by takatsu, Feb 24, 2013.

  1. takatsu

    takatsu New Member

    Joined:
    Jan 2, 2013
    Location:
    Georgia
    Hi!

    I replaced a Peerless pressure balance shower valve body (female with threaded/pipe dope connections) with a a different Peerless pressure balance valve body (male with solder connections). Now when I open and shut the shower valve or either of the master bath sinks (both hot and cold, all upstairs), I hear water hammer. This happened when I worked on the old valve before, but it was simply a case of not burping the lines to a tub in the master bath. When I burped the lines, the water hammer went away. I went back and turned on all the upstairs faucets and flushed the commodes, effectively running water through all the upstairs plumbing. I still have the water hammer. (I turned on all faucets around the home on the lower level independently- no air.) My home pressure is 60 psi due to a household PRV I installed two months ago. What could be going on? The hammer is loud enough I would have noticed it before.

    Thanks!!!

    Paul
     
  2. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Joined:
    Sep 2, 2004
    Occupation:
    Retired Systems engineer for defense industry.
    Location:
    New England
    Sometimes, it's just that you don't have the pipes anchored well. Most of the time, a shower valve doesn't need a hammer arrester, but some do call for one in the installation instructions. Any fast closing valve can create a water hammer and valves that close quickly should have an arrestor nearby.
     
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  4. takatsu

    takatsu New Member

    Joined:
    Jan 2, 2013
    Location:
    Georgia
    Jim,

    Thanks! I checked, and the shower valve doesn't require hammer arrestors- thanks for the advice. I only replaced the shower valve, a 4" run on one side, and a 6" run on the other (to elbows). Three faucets (shower valve itself, left and right lavatory faucets, both hot and cold) make a hammer sound that originates in the same place- away from all three. I think I'll drain the system, refill, and see what that does. Pipes not anchored well may be the cause as you indicate also. I don't think any pipes in my home were anchored during its construction in 1980.

    If there are any other other ideas, please let me know.

    Thanks again!

    Paul
     
  5. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Joined:
    Sep 2, 2004
    Occupation:
    Retired Systems engineer for defense industry.
    Location:
    New England
    It's hard to create a water hammer with a 'normal' valve. It sounds like the main supply pipe to the bathroom group needs to be dealt with. If you listen carefully, you may be able to isolate where this is happening and not need to tear up too much wall to accomplish what's needed. Moving pipes can eventually cause a leak by rubbing a hole in it.
     
  6. hj

    hj Moderator & Master Plumber Staff Member

    Joined:
    Aug 31, 2004
    Occupation:
    Plumber
    Location:
    Cave Creek, Arizona
    Peerless valves are a subset of Delta and are just "rebranded" Delta valves, (in fact I have not seen a "new" Peerless valve in years). We would need a picture of the installation itself to try to make a diagnosis.
     
  7. takatsu

    takatsu New Member

    Joined:
    Jan 2, 2013
    Location:
    Georgia
    HJ,

    See attached image. The replacement was at the top two elbows on the left and right. Everything below that was original.

    I started considering what may be going on to produce the water hammer sound. There is a small check valve assembly in the shower valve. Both the hot and cold side have their own check valve. Again, I can produce the banging sound by turning the cold or hot (individual handles) off or on at two separate lavatory faucets in the master bath or by turning the shower valve on. I suspect there is a problem with the check valve assembly, and what I'm hearing is it reacting to a drop in pressure. I tested my hypothesis by turning the hot and cold on at exactly the same time- guess what- no banging. The previous single handle shower valve also had a check valve assembly, but there was no banging. I'm thinking my options are to make sure I put the assembly together correctly or somehow defeat the check valves, which is probably against code. (However considering there is a check valve at the street, the more likely problem is water hammer eventually ruining something.) Ideas?

    Thanks,

    Paul

    IMG-20130225-00004.jpg
     
  8. hj

    hj Moderator & Master Plumber Staff Member

    Joined:
    Aug 31, 2004
    Occupation:
    Plumber
    Location:
    Cave Creek, Arizona
    That is an interesting photo, because even though Peerless and Delta BOTH have the same address, that is NOT a Delta design, nor does it use a Delta unit, although it uses Delta's parts numbering system. Therefore, it is hard to tell how its balancing feature works or if it could be causing your noise.
     
  9. rfsmith48

    rfsmith48 Member

    Joined:
    Feb 23, 2008
    Location:
    Colorado
    Potential for water hammer....(?)

    Folks,

    I am doing the same project right now. Existing plumbing does not have any water hammer arrestors. System has a 5 year old PRV set at 40 psi. Never had any water hammer problems when the old PRV was allowing 65 psi and more.

    40 year old valves are being replaced with a Kohler pressure reg. SHower valve, and 1/2 turn valves on the vanity. Am I gonna be OK, or do I need to add water hammer arrestors? If yes, I am guessing vanity only..

    TIA,

    Rog Smith
     
  10. takatsu

    takatsu New Member

    Joined:
    Jan 2, 2013
    Location:
    Georgia
    Water hammer after pressure balance valve install- fixed!

    Hi! I did an online chat with Peerless and their "Faucet Coach." While these people haven't been very helpful in the past- I suspect they are not plumbers or have even worked on or know much about their products, but they can read a script that helps troubleshoot what I suspect are common problems. They told me to take the valve apart and flush the lines with no cartridge in place. A bunch of stuff came out. I was at the street side. My wife held the bucket, and we flushed several times until the water carried no more stuff out. I also noticed both the hot and cold check valves had small solder pieces in them. I cleaned that out, reassembled the valve, and no more problems. No hammering sound, etc. We can put this in the problem solved column. By the way, I don't plan to put in water hammer arrestors as the original installation didn't have them. What is strange is I've soldered before and never had solder flakes come off. The only difference this time was I was using a different flux than before. The copper was nice and shiny with good wetting.

    Thanks,

    Paul
     
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