Ok, here's my plumbing question:

I've got this noise coming from my basement. It's a vibration that comes and goes throughout the day. WAIT - don't say "water hammer" yet, read the rest of the problem!

It seems to be coming from the general area where my supply line enters the house. All of these pipes are connected to the floor joists for the main floor so the vibration resonates through the floor and can be easily heard in my dining room above.

We've been in this house since 1992 and never noticed this problem until we had some plumbing work done (by pros, not me!). 1) We replaced the plastic pipe from the street with copper and 2) We had a new water heater installed.

I can't really isolate the exact source of the problem. It seems to be coming through the supply line from outside the house but I'm not certain. Sometimes it seems like it's coming from the pressure reduction valve that's in the same area.

There seems to be no correlation between the noise and any use or non-use of water within the house. In other words the noise does not start immediately after a toilet is flushed or a faucet is opened or closed.

The sound is a vibration that lasts up to 30 seconds or so. It's not violent or excessively loud but if you're in my dining room you can certainly hear it.

Ideas?

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Bill Wood - Retired Webmaster
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The copper line, being metallic and stiffer than the replaced plastic line, is a more efficient conductor of vibration. The problem may have pre-existed the replacement of the line.

Is your house proximate to railroad tracks or areas that see heavy vehicle traffic?

Why don't you get your wife (or other handy helper) to go to the cutoff at the street and slowly close and open it while you stand under the pressure reduction valve to see if that is the problem? My house is a 1928 and has probably half copper and half pvc and Paul C is right--the copper is a lot louder. I have had to re-strap some of the copper to the joists to keep them from banging.

No railroad is near my house.
There's a 2-lane street 2 houses away that's pretty busy.

__________________
Bill Wood - Retired Webmaster
My Personal Website
1998 Mercedes E430
2010 Toyota Sequoia
My Photo Albums

Try to see if the vibration coincides with the passage of a heavy vehicle on that street. The issue may be a water line that, through settling of the fill around it, has a section in an air pocket and might be acting like a tuning fork whenever a source of vibration is in the vicinity.

That's an easy enough experiment to try.

I actually bought some neoprene insulation and put it on the pipes hoping it would dampen the vibration but it didn't help much. I also bought, but haven't installed, some new plastic hangers that are large enough to put rubber insulation between the pipe and the hanger for additional isolation.

__________________
Bill Wood - Retired Webmaster
My Personal Website
1998 Mercedes E430
2010 Toyota Sequoia
My Photo Albums

Odd Bill... I don't have the answer but I posted your question on a plumbing forum... the guys there know their stuff, but they are a little condescending at times. Let's see what they say.

Silly question, and a long shot. Is there an expansion tank on your water heater?

Yes, the new water heater has one. The old water heater did not.

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Bill Wood - Retired Webmaster
My Personal Website
1998 Mercedes E430
2010 Toyota Sequoia
My Photo Albums

Ah... OK!

Experiment time.

Can you turn off your water heater, and I mean OFF... and then open the HOT water taps in the house. Also, turn off the supply going TO (and if there is one - FROM) the water heater.

Now... wait and see if you get the noise.

(When I mean turn off the water heater, cut the pilot light or the power to it, and turn off the water to/from it, then drain the pipes by opening the taps). We're taking the hot water tank (and possible inline-expansion) out of the equation.)

Does it occur when water is being drawn?I had a copper pipe venturi effect harmonic where the 1 inch black iron supply line narrowed to a 5/8 copper pipe and telegraphed to the joist hangers. Solution?cut the copper line and put a length of heater hose connecting it,2 hose clamps each,I tend to get carried away.

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There seems to be no correlation between the noise and any use or non-use of water within the house. In other words the noise does not start immediately after a toilet is flushed or a faucet is opened or closed.

__________________
Bill Wood - Retired Webmaster
My Personal Website
1998 Mercedes E430
2010 Toyota Sequoia
My Photo Albums

Before I do all of that can you fill me in on your hypothesis?

__________________
Bill Wood - Retired Webmaster
My Personal Website
1998 Mercedes E430
2010 Toyota Sequoia
My Photo Albums

It's not really much to do Bill, I promise.

But the idea is multi-fold.

First, in many cases, if the pressure tank wasn't matched or installed properly you have issues with the actual pipes becoming a "backup" expansion tank... this will cause noise and/or the pressure valve on the hot water tank to blow (not your issue).

Second, and most obvious, is that you basically had two different bits of work done. The tank, and the line change.

So, we want to use process of elimination to resolve your issue.

There are some other issues that this will "test" as well... so give it a whirl. It should take a total of 15 minutes... depending on how often the noise usually happens.

If you perform the test, and STILL have an issue with the noise, we move on to the next plan.

Pete

(
Here's a heads up to the next plan:

Pressure reduction valves sometimes hum or vibrate slightly...
)