Water hammer or loose pipe...

ElectraTooFebruary 24, 2013

My house is brand new. We have a 50 gallon gas water heater by A.O. Smith. Has an explansion tank and a circulating pump installed.

I'm not sure if this has been happening all along but in the last week or so I've noticed that when the flow shuts off to the washing machine, or the toilet tank refills after flushing, and sometimes when a faucet is turned off, there's a loud thunking sound. Seems to be loudest in the wall behind the water heater. We are on city water and I'm not sure what the exact pressure is, but it's definitely pretty strong because I don't think I've lived anywhere with pressure this good.

A cursory Google search leads me to believe this is water hammer, but I've read some other stuff that talks about pipes not being strapped adequately. Since I'm hearing the sound in the wall, I'm wondering if that could be a possibility as well? Is there any way to know short of installing arrestors and seeing if that solves the problem? Additionally, do we install the arrestors on all of the valves that are exhibiting the problem, or is there some central location where one could be installed and control flow to all parts of the house?

Finally, does the expansion tank play any role in reducing hammer?

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Arrestors go near each quick acting valve.

    Bookmark   February 24, 2013 at 1:23PM
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1st Choice Plumbing
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Drain cleaning, Faucet replacement, water heater replacement, Plumbing repair work. Plumbing service and emergency plumbing.
Free home plumbing inspection with any other plumbing service.
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This is a full service residential and light commercial plumbing company that has been serving the greater Baltimore area since 1992. Available 6 days a week from Saturday evening until early Friday afternoon.
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Here is a link that might be useful: 1st choice plumbing inc

    Bookmark   February 24, 2013 at 4:03PM
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I think A1 Plumbing of Baltimore hires folks that either:
A) Can't read, or
B) Are thieves.

You don't get to attempt to steal advertising space on this site. By doing so, I have to assume you are incapable of reading the site TOU or that you don't care. Either way, were I in the Baltimore area, I would not hire a plumber who is either uneducated or dishonest.

You asked.

    Bookmark   February 25, 2013 at 10:21AM
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The expansion tank is there do deal with the pressure variations caused by the hot water heater cycling on and off over time. This implies that you are on a 'closed' system from the city supply and have a PRV (pressure reducing valve) somewhere in your system. It may be outside at the meter or inside near where the water line comes into the house and the main shutoff valve.

It wouldn't be bad if you went to HD or Lowes and purchased a pressure gauge to measure your pressure. They don't cost too much and attach to a hose spigot.

Here is a link that might be useful: watts gauge

    Bookmark   February 25, 2013 at 3:45PM
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I have been noticing "hammering" with my new washing machine - HE. It shuts the water on and off so abruptly. I have heard that special valves can be installed at the washer shutoff to alleviate this, is that a good idea?

    Bookmark   February 25, 2013 at 4:53PM
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