Replies

1. 
   Dave45 | Jun 21, 2006 06:19am | #1

   I doubt if venting the line will fix the problem, but it can't hurt to try.  If your water lines are accessable, have someone run the water as you've described while you watch the lines.  I'm betting that your cold water line needs some support and it's banging against something.

   Is the strainer screen in the faucet clean?  I've had diminishing flow problems when it was partially clogged with crud.  Clean it and you're back in business.

2. 
   BillHartmann | Jun 21, 2006 06:53am | #2

   It is not caused by air in the lines.

   When you have continous hammering (which can range from a bang, bang, to a fast machine gun sound, to whistling( as water is running it is caused by something in the waster flow that is moving and rapidly reducing the water flow and then moving away.

   Most of the times it is a loose washer in faucet (or damaged/worn cartidge/seals in newer style units).

   A hammer arrestor might help smooth out the hammering, but it is realy not a solution.

   A hammer arrestor is used when you have fast moving water that is suddent shut off by a solenoid valve (clothes washer/dishwasher). And it make a single bang possible followed by rattle, rattle.

   
   

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   Edited 6/20/2006 11:56 pm by BillHartmann

1. 
   Doc | Jun 21, 2006 12:51pm | #3

   I've tried watching the and holding the pipes while someone turned the water on and off.  Nothing is hitting anything or unsecured.  I tried removing the strainer on the faucet, and that made no difference.  The faucet is a Grohe.  Originally about $380 faucet.  The sink was a floor model and clearanced, and they were unable to get the faucet off of the sink.  The faucet requires 3 holes - each handle and the faucet are only connected by water lines underneath.  The guy at Lowe's thought the vendor setting up the display used some type of epoxy or lock tight on the threads.  For what it's worth, I tried as well and it won't budge.  Anyway, they made me a deal on the package that was so cheap I couldn't refuse because it was the sink I truly wanted.  I got zero literature with the faucet.  I've written to Grohe, and I've gotten no reply from them.  I would like a parts list or schematic so I know what type of cartridge to order.  I can't find a model number of any kind on the faucet.  I guess I should pull the cartridge out and inspect that first.  Thanks again.

1. 
   BillHartmann | Jun 21, 2006 02:18pm | #4

   You can start here.http://www.groheamerica.com/t/25_4866.htmlIf you click on a series then it will give you the different models in that line. And then click on the specific version it gives you the parts list and exploded view.And at the bottom Under Contact US there is a tech email ady. And a list of distributors.But if you have a compression stop valve on this I would check that first.

3. 
   HammerHarry | Jun 21, 2006 03:06pm | #5

   It doesn't sound like classsic "water hammer" by your description. 

   - you say it starts after the cold water has been running for a while, and then the flow drops off to nothing

   -you say if you turn on the hot water to that sink, it goes away

   I'd bet a milkbone it's a loose washer or cartridge in the cold tap.  It probably starts to "flutter" and that causes the hammer and the loss in flow...turning on the hot water provides some back pressure into the spout (I'm making the assumption that the hot and cold share the spout here) and stabilizes the washer (or cartridge, depending on the tap design).

    

4. 
   chile_head | Jun 21, 2006 06:37pm | #6

   If you have flex lines running to the faucet, you might want to try switching hot and cold. It's an easy, and very confident, way to see if the problem is with the faucet, or upstream in the line.

1. 
   ewing | Jun 21, 2006 07:31pm | #7

   The original poster mentioned that the problem began when the garden hose started to be used.  If the sill cock is left open when the hose is not in use, the garden hose itself becomes an energy storage element -- in effect, a spring -- that can give rise to a resonance not otherwise present.  This is because the garden hose, unlike the rest of the piping (except maybe flexible tubes below the sink), is elastic.  It's simple to test this hypothesis by getting the hammering started, then opening or closing the sill cock to see if anything changes.

   That said, I agree with other posters that the root cause is likely a loose washer or cartridge in the faucet.

5. 
   sungod | Jun 21, 2006 08:02pm | #8

   Water pipe Hammering happens when you turn on the water full blast and then shut it off quickly. Stopping the water quickly will result in one bang or rattle.
   Your description of the noise getting louder as the volume of the water flow increases sounds like a loose washer, seat or valve. The loose item becomes a vibrating reed like in a musical instrument, it change tone with water speed.

1. 
   HammerHarry | Jun 21, 2006 08:55pm | #9

   The reason that water hammer is so loud is that the shock wave travels through the water at the speed of sound, and the pressure surge can be huge.

   Many years ago, one of the local paper mills used a 6 ft diameter, wood stave inlet pipe to bring fresh water down to the mill (gravity flow, not a lot of pressure).  The main inlet valve at the mill failed, suddenly slamming shut.  The pipe erupted in a huge blast of wood, water, rocks, earth, etc etc.

1. 
   Doc | Jun 22, 2006 12:56pm | #10

   I seem to have fixed the problem.  The shut-off valve for the cold water was not open all the way by about a one-half turn of the handle.  I opened it that extra half turn and the machine gun sound has stopped.  I'm suprised that a slight change in the flow made that big of a difference, but I couldn't have asked for a more simple fix.  Thanks for all of your advice on this.