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I live in a 4 plex apartment building built in 1926. Both my neighbor and I, who is on the second floor next to me, have been experiencing a loud vibrating sound when our cold water in the kitchen is turned on past a certain point. It seems to have become worse over the last few months. It is now so loud that it can be heard in the basement of our building and it vibrates the pipes in the bathroom. Does anyone know what is causing this and more importantly what can be done?
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Sounds like a bad case of water hammer. In many cases, the culprit is a riser supplying a faucet or toilet or whatever that does not have an air chamber installed above the valve. This can be done at any time and is usually the best way to cure this problem. It will involve cutting out the line below the valve, installing a “Tee” fitting, and sweating in a copper tube air chamber about a foot long with a cap on top of the tee. This will allow air inside the line to expand and have somewhere to go, reducing the “hammer” you are hearing and relieving that pressure and abuse on the pipes themselves.
Water hammer can manifest itself in quite a few ways, so sometimes it’s difficult to pinpoint the exact cause. Sometimes dishwashers can produce it with thier notorious mixing valves. Matter of fact, mixing valves in general are notorious for causing this phenomena, including those that are installed to prevent toilet tank condensation. Best way to find out is just listen carefully to the area you hear it coming from loudest, as you turn on the particular tap or source that produces it, and try to determine what line it’s coming from, and determining again if an air chamber on that line would do any good. Sometimes it’s a hit and miss proposition, but usually any experienced plamber will be able to locate and repair the problem relatively quickly. though it may involve cutting into a wall to expose and work on the problem riser/line. -
Also, a couple other things I should point out quickly. First, in older buildings like yours, it’s common for none of the plumbing to have any sort of air chambers installed anywhere…..they just did’nt do it back then. Also, another thing you can check is the angle stop valves to your kitchen faucet. Try turning these, especially the cold water valve. If it’s not all the way open sometimes water hammer can be caused by the faucet being full open but flow restricted by a half open valve. Or, you could even try closing it some, whatever works. It could be the valves are getting very old and corroded internally, restricting water flow to the fixture. This would be an easy fix, and hopefully it’s something as simple as that. Also, and not to discourage you but, in really old buildings like that many times you’ll find original galvanized iron supply lines which are older than dirt and consequently very corroded and or/plugged up internally, possibly causing the water hammer effect you describe. I’ve seen it many times in pre-1950’s structures. In this case, only cure would be to locate the bad line and replace it. Let’s hope that’s not the case.
» This message has been edited by AKPlumber on 04 December 2004
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Just want to comment on this water hammer issue. Water hammer traditionally refers to the banging sound when a faucet is shut off. This is due to the momentum change when a moving column of water inside the pipes is suddenly stopped. The momentum is transferred to the pipes and they vibrate. This is not what Calli described, which is a banging when a valve is opened beyond a certain point. However, the machanism is the same, i.e. a sudden change in the momentum of water moving through pipes.
As RP said, loose washers that do not engage smoothly and instead “wobble” as the valve is turned are the most common cause of this kind of water hammer. Another common cause is excessive water line pressure. Therefore, you should measure your water pressure and install a pressure limiting valve if it is too high.
Air column water hammer arrestors serve as shock absorbers to water movement in pipes because the air is compressible and water is not.
However, the main cause of vibrating pipes is quite simple…loose attachment of the pipes to the building framing. Pipes that are well-anchored will not vibrate very much.
To summarize what you must do to minimize water hammer: 1) make sure all pipes are well-anchored with proper support hardware; 2) install a pressure limiting valve if your water pressure is too high, i.e. much more than 60-70 psi; 3) make sure that any fixture throttling type valves (which most of them are) operate smoothly; and, 4) go ahead and install a water hammer arrestor at the culprit fixture if you can’t fix the problem by addressing items 1-3. But even better than installing the arrestor at the fixture, if you have the ability, would be to install a water hammer arrestor manifold at the entrance of the water supply line.
NtP
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