loud noise from hot shower

nosoccermomMarch 2, 2013

After a complete bathroom renovation in a condo:
When turning the shower all the way on hot, there's a very loud noise with vibration in the wall. Sounds like it's right behind the shower head. One person said like a lawn mower, the other like a helicopter in the wall.

It doesn't happen with cold water with the shower nor with hot or cold from the tub.

The shower head is firmly attached, doesn't move.

Diverter is from Moen and now single handle (before two handles) to mix.

Plumber fumbled around for two hours, adjusting the hot water scalding prevention thingie (so now you can't crank up the hot as much anymore).
The sound now only comes every now and then.

So, when the next plumber showed up, it didn't make the noise. He claimed that the valve in the diverter was loose and air could come in.

Someone else's theory is that it's related to the high water pressure and can be easily fixed by removing the water saving from the (new) shower head.

Someone else suggested opening up the wall because the pipes are hitting the stud (for what it's worth, the only pipe is the one from the diverter up to the shower head; no additional pipes).


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Probably non-metallic piping which has been firmly clamped against a wooden framing member (big mistake). The piping changes dimensions with changes in temperature--expanding when heated -- no power on Earth can prevent it from doing so.
It slips in the clamp and each such movement produces the chatter that you hear. It may gradually lessen over time with wear on the pipe and clamp. Or open the wall now and correct the problem.
Classroom study of chemistry and physics is helpful in understanding materials and accommodating to the characteristics of those materials.

    Bookmark   March 2, 2013 at 8:41AM
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Supposedly, the pipe is not clamped to anything.

The noise sounds like it's right behind the shower head. Suggestion is that the hot water pressure is too high because of the water saving shower head.
However, at this point, it looks like the noise is not reproducible reliably anymore. Before, there was no doubt whatsoever.

Problem is that I need to know within the next two days whether this requires a major overhaul (opening the wall etc) or not.

    Bookmark   March 2, 2013 at 8:57AM
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Ours does the same and it is actually, in my opinion, lower water flow. We have a water heater with backflow preventers, actually washers in the in and out line, that cut the flow of water through the water heater. Cold water lines do not have this restriction. All hot water will reduce the flow of water, adding cold or all cold increases the flow. Changing to a shower head that has a more forceful stream helps reduce the noise.
Bottom line, hot water is not filling the shower riser all the way and causes turbulence at the top fitting.

    Bookmark   March 2, 2013 at 10:57PM
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