Issue w/ water pressure on newly installed island

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by osx-addict, Apr 30, 2008.

  1. osx-addict

    osx-addict Software Engineer

    Los Angeles
    Hi all..

    We did a remodel last year and finally got the very large island done in March.. Anyway, it's got the proper drain vent for an island per drawings I've seen on this forum. So, my problem is that the hot/cold come down from the attic into the concrete floor and reappear under the island cabinet where they are terminated with your typical sink valves.. Now, I've got a KWC faucet that has water pressure which is <50% of what it should be.. I just disconnected the cold water supply line on the faucet and was able to fill a large vase quickly (great pressure -- what I expected) for about 2 seconds before I heard a WHAM and then the pressure dropped to about 50% of what it started out like.. I was easily able to repeat the problem.. If I closed the valve and started out slowly I could get the full pressure for as long as I wanted.. If I did a sudden open of the valve then I got the loud WHAM and the pressure drop..

    Now, I looked under our other kitchen faucet (installed >15 years ago) and it's got a manifold of sorts for each of the supply lines with a vertical piece (perhaps 6" tall) with a cap on it aside from each valve.. I'm assuming this is working as a water hammer arrestor.

    If I do something similar on the new island, will that solve the water pressure problem? I was the poor sucker that plumbed the faucet/drain on this after our plumber became a pain in the $#$#!@$ when it was time to hook up everything near the end of the remodel..

    Any ideas on this would be greatly appreciated!
    Last edited: Apr 30, 2008
  2. Redwood

    Redwood Master Plumber

    The flow induced wham has me thinking of a couple of possibilities.

    1 A loose washer in the stop valve under the sink.

    2 Debris in the line that moves up to the valve or other restriction then blocks the flow.

    3. Usage of Flood Safe supply lines.

    I take it that the KWC faucet is a pull-out style faucet.
  3. osx-addict

    osx-addict Software Engineer

    Los Angeles
    This I might be able to imagine, but why would it be the same for both hot & cold? Although I'll admit that I've not removed the supply line on the hot side but am expecting the same behavior there. I'll verify that tonight..

    Hmm.. This is a possibility I suppose, but wouldn't expect this from both hot & cold (both seem to have the same sort of pressure loss at the faucet).. If this is a possibility, I'll have to remove the valve and slowly turn on the water supply to purge whatever it is -- correct? This island was the last part of the house to have the caps removed and could conceivably have some crud in there that was too big to get out of the valve I suppose.. Anyone have a good method for doing this w/o flooding the house?

    Nope.. I looked up the Flood Safe Lines and ours are definitely not that type.


    If anyone has any other ideas, I'm all ears at this point. What we have been noticing over the past month or at least weeks anyway is that the pressure just keeps going lower and lower and lower.. At the time I dismantled the supply lines yesterday I'd hazard a guess that the flow eminating from the faucet was probably about 35-40% of what the other kitchen sink faucet gets -- all hot & cold lines in the house are newly installed last summer as part of the remodel -- all in the attic. If it matters, this is on a city water system (no well) and we've got great pressure in the rest of the house except for a cold water line in the kids bathroom (which was also part of the remodel).. It may have the same sort of issue I suppose -- I originally thought it may be something related to the faucet but am now thinking the two have the same symptoms and perhaps the same cure -- whatever it is...
  4. Furd

    Furd Engineer

    Wet side of Washington State
    You do not have a pressure problem, you have a flow problem.

    If your other faucets work okay then your problem is with the new piping that you installed. Please explain IN DETAIL where and how you connected the new piping and how it is run to the island.

    Pictures are always helpful.
  5. Mikey

    Mikey Aspiring Old Fart, EE, computer & networking geek

    Central Florida
    Sounds like debris left in the lines from the installation. I'd remove the stops and flush the lines at all locations with the problems. It's a two-person job...

    1) Turn off water.
    2) Assuming 1/2" copper coming in to the stops, get a few feet of 5/8" ID hose and a worm clamp. Remove the stop (hopefully it's a compression fitting) and attach the hose, using the clamp.
    3) Hold loose end of hose in a bucket while your lovely assistant turns the water on for 2 seconds and then turns it off.
    4) Inspect bucket for crud.
    5) Also inspect stop for crud lodged in it.
  6. osx-addict

    osx-addict Software Engineer

    Los Angeles
    Thanks guys.. I'll provide some pics later today if I've got some time and after my day job.. I've got a bit of photos from the installation the plumbing contractor did in the vertical wall space (before the drywall went up) before it disappears into the concrete.. I can also get some photos under the sink to give you an idea of how things look down there..

    In a nutshell though, all plumbing runs are in the attic (the house originally had plumbing in the slab foundation which was installed in the early 70's -- all copper. We chose to move everything in the attic since we were moving several bathrooms and other plumbing around. Anyway, the plumbing from the attic to the island runs down from the attic into a stub wall (~1' wide IIRC) and then the copper piping runs horizontally through concrete (using the flexible variety here) over to the island -- a distance of approx. 4'. Once inside the island, the flexible copper comes up in a sweeping turn and was capped about 18" off the floor (vertically). I put on your average 1/2" compression x 3/8" compression valve which is what the faucet was looking for and all was good.. or so I thought.. ;)
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