Pipe Banging - Only One Toilet

For the last several months, there is a single banging noise that I can hea r in the walls of my apartment at the end of the tank filling when I flush the master bathroom toilet.
I have tried turning off the water to the whole apartment, opening EVERY si nk/shower/tub valve in the apartment, flushing all the toilets, and waiting until there is no water coming out of all of them. Then I closed all the valves, and turned on the water to the whole apartment. Finally, I turned the sink/shower/tub valves back on until there is water coming back through all of them.
When I flush the master bathroom toilet again, there is still the single ba ng at the end of the tank filling.
The noise sounds like it is coming from the walls instead of the toilet tan k.
I'm at a loss as to what to try next. It only happens when the tank finish es filling after I flush one specific toilet. I don't want to call a plumbe r yet until I've exhausted the things that I could try personally to fix it .
Any help would be appreciated.
Thank you.
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Try closing the valve to that one toilet just a little bit. It may take a little longer to fill, but it might also stop the water hammer.
Another suggestion, maybe to try first, would be to go through the part of the installation process for the fill valve where you turn the water to the toilet off, remove the top of the fill valve, hold it over the tube and turn the water on just enough to flush the valve. That process obviously depends on the type of fill valve you have, but maybe something is stuck in it, causing it to close more rapidly than it should.
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If I'm hearing the banging in the walls, why would the fill valve make a difference?
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Water hammer is typically caused by a fast closing valve that sends reverberations back through the plumbing, often causing pipes to bang against walls. Toilets, dishwashers, washing machines and even some faucets can cause water hammer.
The water is rushing through the pipes towards the open valve. Suddenly the valve closes tight. All of that energy has to go someplace. It may stay "within" the pipe until it finds a spot where the pipe is not secured as firmly as other areas. That section starts to vibrate, banging against the walls. Sometimes the noise is within the pipe itself as the water hits an obstacle such as a 90° fitting or another valve.
Another cause is a faulty pressure reducer valve which can make the water pressure in your house higher than it should be. In those cases, the water hammer might be caused by the closing of any valve, not just a single fixture, but even that's not a sure thing.
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wrote:

Same problem here. Any valve that is closed quickly - even sink valves - cause the water hammer. I closed the toilet valve part way and that stopped it. Can't do that with the washer so it bangs. What's a good pressure range for the cold water line? I checked the water pressure here 20 years ago and remember it being in the 60 psi range but there was no banging then. No pressure gauge right now to check it though.
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You can pick up a gauge for under $15. Well worth it if you are in danger of blowing out fixtures because of a faulty pressure reducing valve.
e.g. http://t.homedepot.com/p/Watts-3-4-in-Plastic-Water-Pressure-Test-Gauge-DP-IWTG/100175467
I think 55-60 psi is a safe, comfortable range. I believe that 60 is what most PRV's are pre-set for. I think I remember reading someplace that the max allowable pressure from a municipality us 85, but don't quote me on that.
When my PRV went bad I was reading 80 PSI. Whenever I turned off _any_ fixture I would hear THUMP...THUMp...THUmp...THump...Thump...thump...thump...thump.
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On Mon, 24 Feb 2014 16:04:58 -0800, "Guv Bob"

Dish washer, or clothes washer? Regardless, you can get a small (4 or 5" long) water hammer suppressor that screws on to either input of the washing machine and the water hose screws on to it. It has an air chamber, with a rubber diaphragm to keep t he water out of the chamber.
when the washing machine turns off the water (suddenly) the air in the chamber is compressed and takes the shock, and stops the banging. Even when mounted on the washing machine, it will work almost as well for the every other valve in the house. If it's a toilet causing the hammer, you have to put the device on the cold water, but even the hot water might cause noise when the hot water valve on the washing machine closes. So you miight need two of them, or maybe only the cold water.
Best to mount them pointing up, so when the diaphragm breaks, water won't fill the space (It takes weeks for the air in the space to be absorbed into the water, when the diaphragm is missing, probably longer when it's just ripped.) Anyhow, I've had mine for 10 or 20 years and it still works fine.

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wrote:

that stopped it. Can't do that with the washer so it bangs.

range but there was no banging then. No pressure gauge right now to check it though.
Thanks, I'll get the gauge and supressor and give it a try. I notice that no matter which valve in the house is closed, the sounds comes from the same point under the floor. Unfortunately, that would be at the very farthest end of the house from the crawl space door. I doubt the lovely wife would want to crawl back in there again.
http://www.homedepot.com/p/Oatey-Quiet-Pipes-Washing-Machine-Water-Hammer -Arrester-38600/100069256
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On 2/24/14, 2:54 PM, DerbyDad03 wrote:

Maybe a little off topic here... but I remember hearing fire hydrants need to be closed slowly for much the same reasons.
An open hydrant, fighting a fire or filling a street sweeper truck can have many tons of water moving very quickly in the water mains leading to it, and if all that water is stopped quickly, it will cause a substantial pressure spike in said main/s and anything connected to it.
I don't know if arresters (accumulators) are used in mains... but suspect not.
Erik
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On 2/24/2014 8:56 PM, Erik wrote:

The hydrants that I've used, typically about 12 to 14 full circles of the hydrant wrench to open or close. The FD does have quarter turn ball valves, including on the nozzles. The quarter turn valves need to be closed slowly to avoid water hammer.
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Actually, water hammer is not caused by a spike in pressure, although that would be the symptom of the disease.
It's caused by momentum. Water is heavy and when it's moving quickly it has a lot of momentum. Momentum is energy. In fact, when Isaac Newton took pen in hand and wrote his first law of motion, he didn't say Force=mass times acceleration, he said Force = the rate of change in momentum, and we're the ones who changed it to the more popular mass times acceleration.
Energy can neither be created nor destroyed, only converted to another form of energy. So when the water molecules in a pipe are forced to stop, their momentum gets transfered to whatever is stopping them from moving STRAIGHT forward in the same direction as the momentum, and that could be an elbow or tee in the piping, or the valve itself. Even if the pipe is securely fastened to the studs and doesn't have any apparant motion, the energy in the momentum of the water will go into stretching that pipe and bending whatever is holding the pipe from moving ever so little before they elastically retract to their former positions.
Imagine a crowded bus making an emergency stop. The people standing in the aisle will all be forced to the front of the bus if they weren't holding themselves from going forward. If they weren't holding themselves steady, the momentum of all those people would be transferred to the front windshield of the bus, possibly breaking it.
I know how the fill valve in a toilet works, and it's a topic we discussed about six or seven months ago in this forum. But, there's nothing I can think of that would make a fill valve close any faster than it normally does, except a higher water pressure. But, I can't see that difference accounting for water hammer.
The way they fasten down piping in the walls I've had any intimate knowledge of is to notch the studs about 8 to 10 inches above the floor and run the piping in the notches. Then they nail a metal plate over each notch and put up drywall to cover everything. Sometimes the plumbers will stick little pieces of wood between the pipe and the metal plate to wedge the pipe in place and keep it from moving.
I'm afraid that whatever was holding that pipe in place has come loose over the past while and the pipe is free to move in the wall now. And, so the result is that you can hear the pipe shaking in the wall when flow stops abruptly.
What should help some is water hammer arrestors. Basically, they're a piston in a sealed cylinder. The momentum of the water pushes on the piston to compress air in the cylinder. But, if you put in a water hammer arrestor, it's important to install it so that it's in the same linear direction as the momentum of the water. That means, if you have a 40 foot horizontal copper pipe coming from your cold water supply, and a 2 foot vertical pipe going up to your toilet's fill valve, the water hammer arrestor should be installed horizontally at the toilet end of the 40 foot long horizontal pipe, not at the toilet end of the 2 foot vertical pipe. Or at least, it'd be most effective in absorbing the momentum of the water if installed horizontally. Ad vertisements that show them installed vertically are aimed at selling water hammer arrestors. If they told you to crawl into the crawl space under your house and install them there, you wouldn't buy them.
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Erik wrote:

hydrants to quickly.
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On Mon, 24 Feb 2014 20:12:37 +0000 (UTC), DerbyDad03

For that matter, you can close the valve to that one toilet a lot, almost fully. (assuming the toilet doesn't use a Flushomter) It may take 15 minutes for the toilet to refill, but if you live alone or are the only one who uses the toilet, so what?
It also won't make any noise when it's refilling if it's closed a lot. Helpful when people are trying to sleep.

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tj,
You used the word "apartment". Do you own this apartment? If not notify someone of the water hammer problem and let them hire a plumber. On the other hand if you are the owner can you drain your plumbing without affecting your neighbors? Hammer arrestors some times get water-logged. If you drain the plumbing system air gets back into the arrestor. So drain the plumbing. Give it 10 mins to drain. Then turn on the water. Expect rusty water. Close the faucets and clean the crud out of their aerators. Flush the toilets. Clean the shower heads. If that doesn't work get a plumber.
Dave M.
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I recommend that the OP shut the water off to the toilet completely, flush the toilet, and then turn the water back on a very small amount, so that th e toilet takes at least 60 seconds to refill the tank. If it is a "hammer" problem, that slow a fill rate should end any hammer sounds. If it does, then open the fill valve a little more and repeat. Keep doing this until t he hammer returns, then close the valve a little bit and get a good mights sleep.
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