Water hammer

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Howdy folks! When the toilet shuts off, I hear a fairly loud water hammer now. Never had that happen before until recently and have not had any plumbing work done. I did a little net research and see that this could cause damage or leaks in the piping, so I'll have to get on this one quick. But before I jump into it head first, I've gotten a lot of good advice here and thought the great mind might have some tips.
A couple of questions -- since it just started, I'm wondering where the air could have come from? I've tried running the water in all the faucets high and low to try and bleed it but don't see much difference.
I've read that it could be on the downstream or upstream side of the valve - do you know any way to tell? Sounds like there are different things to try and I'd just as soon start with the most likely and easiest ones first.
Some more info (pull up a chair, boys, LOL!!)... the toilet, sink & tub all tee into the same line within a couple of feet of each other, but only the toilet hammers. Also, in the other end of the house - about 30 feet downstream of the toilet, the kitchen sink faucet hammers.
Welp, that's my story. Any help or good guess much appreciated.
Bob
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Howdy folks! When the toilet shuts off, I hear a fairly loud water hammer now. Never had that happen before until recently and have not had any plumbing work done. I did a little net research and see that this could cause damage or leaks in the piping, so I'll have to get on this one quick. But before I jump into it head first, I've gotten a lot of good advice here and thought the great mind might have some tips.
A couple of questions -- since it just started, I'm wondering where the air could have come from? I've tried running the water in all the faucets high and low to try and bleed it but don't see much difference.
I've read that it could be on the downstream or upstream side of the valve - do you know any way to tell? Sounds like there are different things to try and I'd just as soon start with the most likely and easiest ones first.
Some more info (pull up a chair, boys, LOL!!)... the toilet, sink & tub all tee into the same line within a couple of feet of each other, but only the toilet hammers. Also, in the other end of the house - about 30 feet downstream of the toilet, the kitchen sink faucet hammers.
Welp, that's my story. Any help or good guess much appreciated.
Bob
Water hammer is not caused by air in the pipes. In fact air in the pipes would help prevent it. Your problems are probably caused by the toilet shutting the water off too quickly. Changing or repairing the ballcock may cure the problem.
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wrote:

Simplest thing to try first:
Stolen without permission from:
http://homerepair.about.com/od/plumbingrepair/ss/drain_plumb_sys.htm
Draining the Plumbing System
To drain the plumbing system proceed as follows:
Shut off the main water valve at the water meter Starting at the top floor, open all the sink faucets; Go to the basement or the lowest level in your home and open the faucet in your laundry tub and let all the water from the above floors drain out; Now go back upstairs or to the highest level in the home and open the tub/shower faucets; Now go flush all the toilets; Leave the faucets in an open position;
Charging the Plumbing System with Water
To activate the plumbing system and refill it with water proceed as follows:
Close the basement faucet or lowest level faucet in the house; Now close all the upper faucets. Closing the faucets allows air remain in the pipes to recharge the air chambers you may have in your home's plumbing system; Go back and open the main water valve to let the water back into your pipes; Now, one by one, starting with the highest level faucets, turn on the faucets and let the air/water sputter out until only clear water flows from the faucet. You may see discolored water come out at first, this is normal. Open the shower faucets; Flush the toilets Once the water is running clear, turn off the faucets starting at the highest floor level and work your way down through the house. You may have an occasional sputter the next time you use a faucet but any remaining air will quickly be purged.
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My City had replaced many tuberculated water mains and one day I was in my basement while a load of washing was going on upstairs. That washer had a rinse cycle where fresh water was sprayed into the sidewall of the tub as it spun, to flush though the load and help remove any residue. That valve cycled about 2 secs on, and 6 secs off, for about 3 minutes. It always made a hell of a racket when in that cycle with the water hammer. I had also a year before replaced the very badly tuberculated 3/4" gal. main with 3/4" copper. This day while in my basement I was standing next to the hot water tank and as the hammer occured, I noticed that with each shut-off of the washer, the safely valve on the hot water tank spit a decent stream. I checked the tag on the safety valve and it said it tripped at 175 psi. Next day I purchased a water pressure gauge and installed it and was shocked to see my pressure was 110 psi. The hammer was jacking my pressure over 66 psi. I immediately purchased a 1" pressure regulator and installed it and dropped my working pressure down to 45 and now all is well. My sprinkler system seems to work fine at that pressure and should last much longer than at that high pressure. . . . My badly plugged 3/4" Gal main had evidently provided just the amount of resistance so that the higher pressure didn't seem to be noticed at the working end. The new copper main changed all that. Now I can shower with a sprinkler zone operating and not get any change in my shower water using the 45 psi setting. Copper was .50 cents a pound when I bought my $60 regulator...hate to see what they cost now. An experienced pipefitter told me to get a regulator a size bigger than my main...Before this modification I could not keep washers in the valves in my bathroom or kitchen. No problem now. I did 'open' the inlet holes on my toilet tank valve as it took quite a time longer to fill at the lowered pressure.
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Chas wrote:

"Tuberculated water main" = Rust or scale build-up in the pipe
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"Plumberosclerosis". Narrowing of the pipes. New word, just invented it.
Christopher A. Young Learn more about Jesus www.lds.org .
Chas wrote:

"Tuberculated water main" = Rust or scale build-up in the pipe
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Watch out for the kidney stones ...
--
Best regards
Han
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On 2/13/2012 6:27 AM, HeyBub wrote:

we also have about 110 psi. Makes for a nice garden hose pressure if you keep your hose outlets before the regulator. <G>.
PS: don't use the yellow hoses from Walmart. LMAO!!
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Steve Barker
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I also have my hose spigots before the regulator.
The front one was before the regulator when we moved in, but the back one was after.
My first use of Pex and Sharkbites was to tap into the pipe for the front spigot and run a line across the basement ceiling to the back spigot to get street pressure to that one.
Sharkbites in the joist bays and Pex over the ductwork made it a real easy upgrade.
SWMBO was extremely grateful since it cut her garden watering time in half.
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On Sun, 12 Feb 2012 19:37:43 -0800, "Guv Bob"

now. Never had that happen before until recently and have not had any plumbing work done. I did a little net research and see that this could cause damage or leaks in the piping, so I'll have to get on this one quick. But before I jump into it head first, I've gotten a lot of good advice here and thought the great mind might have some tips.

could have come from? I've tried running the water in all the faucets high and low to try and bleed it but don't see much difference.

you know any way to tell? Sounds like there are different things to try and I'd just as soon start with the most likely and easiest ones first.

tee into the same line within a couple of feet of each other, but only the toilet hammers. Also, in the other end of the house - about 30 feet downstream of the toilet, the kitchen sink faucet hammers.

You should see some vertical capped pipes in your water system. These basically serve as air chambers to absorb shock. In my house there are only 2, one on a hot and one on a cold water feed to the basement laundry tub faucets. About 18" long. They serve the entire house, since they connect to all hot/cold lines.
If you have these capped lines, the usual explanation for water hammer is they have filled with water because over the years the oxygen in them was absorbed by the water. The solution is to drain all water to below their level, so the water in them can gurgle out and be replaced by air. If you don't have these air chambers, I don't know what to tell you. Always had them in my houses.
--Vic
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Before I caught my hot water tank venting during the water hammer I had inserted two 4 foot 1/2" copper capped tubes vertically inside the wall above my washer water shut off valve, trying to make a resevour to capture air to dampen the hammer. That didn't work. Later in my basement I silver soldered some refrig valves (Schraeder) into the hot and cold lines under my laundry room. I have an air compressor in my basement and a 'main' with many quick connects. One was handy to this area and I injected air into the laundry water feed lines, but didn't get much result. This was a waste of time and money. The regulator was the trick.
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wrote:

There you go. If water pressure is too high there's enough shock to overcome what the air chambers can absorb, and hammer anyway. You fixed it.
--Vic
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A proper water hammer arrestor is the solution. Either piston or bellows style.
http://www.watts.com/pages/_products_details.asp?pid=741 http://www.watts.com/pages/_products_details.asp?pid=7137
cheers Bob
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On 'This Old House TV' they put a hot water house heat type expansion tank (with the rubber bladder inside) on a hot water tank. They said a pressure regulator or meter would be a check valve and without use the hot water would expand and raise the pressure considerably. *********************************************** A proper water hammer arrestor is the solution. Either piston or bellows style.
http://www.watts.com/pages/_products_details.asp?pidt1 http://www.watts.com/pages/_products_details.asp?pidq37
cheers Bob
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Chas-
I don't understand your follow up post.
Pressure regulators don't necessary have or act as check valves, neither do water meters.
Houses with back flow preventers or check valves can experience water temporary water pressure increases due to the expansion of water when heated from house inlet temperature to water heater temp.
IIRC about 1.5% from 45F to 135F, so with a 50 gallon water heater you'd need ~.75 gallons of expansion uptake to prevent a pressure rise. This assumes your entire water is filled with 50 gallons of cold water and there is no usage of water while the water is heated.
If someone uses water (hot or cold) as the water heater is heating up, there will be much less pressure rise due to the fact that extra pressure cannot build up...... the water usage acts as a relief valve.
cheers Bob
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On 2/13/2012 2:26 AM, DD_BobK wrote:

a pressure regulator will always act as a check valve.
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Steve Barker
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On 2/12/2012 11:43 PM, DD_BobK wrote:

foot long air chambers have worked for decades and still do.
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Steve Barker
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Not in my experience.....
I have a house built in 1930 that originally had galvanized steel plumbing, complete with 12" to 18" air chambers which never worked very well.
The 85 psi water pressure delivered to the house via a 1" copper line might have been the problem.
Since the house was re-piped with PEX and had the following added... double check valve pressure reducer water hammer arrestors on toilets, washing machine & misc other locations
no more water hammer.
cheers Bob
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On 2/13/2012 11:03 PM, DD_BobK wrote:

lowering the pressure on the old system would have worked wonders also.
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Howdy folks! When the toilet shuts off, I hear a fairly loud water hammer now. Never had that happen before until recently and have not had any plumbing work done. I did a little net research and see that this could cause damage or leaks in the piping, so I'll have to get on this one quick. But before I jump into it head first, I've gotten a lot of good advice here and thought the great mind might have some tips.
A couple of questions -- since it just started, I'm wondering where the air could have come from? I've tried running the water in all the faucets high and low to try and bleed it but don't see much difference.
I've read that it could be on the downstream or upstream side of the valve - do you know any way to tell? Sounds like there are different things to try and I'd just as soon start with the most likely and easiest ones first.
Some more info (pull up a chair, boys, LOL!!)... the toilet, sink & tub all tee into the same line within a couple of feet of each other, but only the toilet hammers. Also, in the other end of the house - about 30 feet downstream of the toilet, the kitchen sink faucet hammers.
Welp, that's my story. Any help or good guess much appreciated.
Bob Try the easy thing first. Change the washer/diaphragm on the float valve first. Often cures the problem. It's not always air.
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