Water Hammer problem

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Topic: Water Hammer problem

Home and Garden April 3, 2014 at 10:51 pm

Water Hammer problem

Hi – – We have recently noticed a pretty serious sounding water hammer when we flush one of our upstairs toilets (3 story renovated rowhouse in Petworth). We have only noticed it for the last 6 weeks or so, but we must admit that does not mean it was not happening earlier, it may have been and just gotten louder to the point we noticed.

We have tried all the do-it-yourself tricks. First we drained the whole system and restarted, and it went away for about 2 flushes. Then we tried decreasing the water flow in to the tank, but no real change occurred on the water hammer.

Has any one dealt with this? Do you suggest we call a plumber? I am not sure how damaging this sort of thing can be. I see mixed reviews online about water hammer arrestors, and I am not sure one would help in our case as the sound does NOT seem to come from anywhere near the toilet/bathroom walls but from someplace else in adjacent walls. It is usually 2-3 loud bang/clunk sounds immediately post flush.

I welcome any advice from folks who have dealt with this before as the sound is increasingly disconcerting, but we are a bit afraid of calling someone in to only get taken advantage of if this is not actually that big a deal or there is some other trick we should have tried. We are also scared they will have to tear up a significant portion of our house to find the offending pipes, and we are expecting a baby in June so not an ideal time for chaos….

Thank you for any advice!

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This doesn’t sound like typical water hammer. Water hammer occurs when a valve *shuts* – i.e., after the toilet tank has stopped filling. The “hammer” results from moving water immediately stopping as the valve quickly closes.

If you are getting a clunk when you flush it is probably something else – perhaps a pipe in the wall is loose, and when the valve opens and water starts moving it causes the pipe to move slightly, bouncing against a stud.

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