# #&*@! Water Hammer!



## Mike Finley (Apr 28, 2004)

Finally had a chance to get the hot water turned on in this rental townhome. Spent a great deal of time cutting out an old solar heating system in the garage and reconnecting the water lines back together.

I turned on the main, filled the hot water tank, lit the fuse and awesome, got hot water in a little while. Unfortunately turned on a hot water shut off and sounded like a jack hammer.

I have to installed anti-water hammer devices for the washer, will this be enough to take this water hammer out, or do I need to do more?


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## mdshunk (Mar 13, 2005)

An XTrol on the water heater is another excellent remedy.


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## JamesNLA (Jun 2, 2006)

It's more or less the same thing. If it's just in that one area, that give it the bandaid, if you hear it in a few places, than the latter.


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## Double-A (Jul 3, 2006)

Finding the source of water hammer is a tough one sometimes. If you didn't have any on the cold side, and this symptom only started when you started using the hot side, then your problem is most likely a valve or a loose pipe on the hot side.

Hammer arresters will go a long way to stopping this problem, especially on fast acting valves like those on a clothes washer or dish washing machine. The fast closure on these valves really set up a hard hammer, but other valves may be the actual culprit. 

If you are still experiencing hammer, it might be a loose washer in a service stop or in a faucet. To determine this, turn off all service stops on the hot side and turn them back on, one at a time until you duplicate the problem. Once you have found the bad area, you can add hammer arrestors or attempt a repair or replacement of the offending part.

Remember, just soldering in a pipe extension that is filled with air is not going to solve the problem for long. Its best to use a commercial arrestor that has a physical seperation of the gas and water chambers.


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## Mike Finley (Apr 28, 2004)

I really need to fix it now, since I won't have a washer installed and hooked up until the very end and now the walls are open or can be opened, so now is the time to do it. 

I will try opening up each hot water sink shut off valve one at a time and see what happens, right now I have only noticed it in the powder room on the lower level because that is what I am using for water. I will try the other two bathrooms tomorrow.

I hear you on the commercial arrestors, I have already bought 2 and was planning on putting them on the powder room pipes anyways.

The plan is to get everything done for the long run then button it all up permanently. I really don't want to have to come back 6 months from now and open anything up or have to discover something that was missed, so I'm trying to cover all the bases now while I'm in the middle of everything.


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## Ron The Plumber (Oct 10, 2006)

Arrestors are to be accessable and not hidden in walls.


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## Mike Finley (Apr 28, 2004)

Ron The Plumber said:


> Arrestors are to be accessable and not hidden in walls.



Say what? You can make ones out of copper that don't work forever and cover them up but factory made ones that work have to be accessable?


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## JamesNLA (Jun 2, 2006)

Mike, You mentioned the walls are still opened why not track down where the problem actually is and take care of it that way? Or is not all of the plumbing accessable?


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## Mike Finley (Apr 28, 2004)

Some are open, some are not, I would open up anything I needed to fix anything needing fixing. How do you track it down?


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## JamesNLA (Jun 2, 2006)

Well...... Did it happen before taking the solar off line? First thing I would do, is go to each fixture and toggle it on and off a few times. Feel the angle stop as it happens and go by loudness and by touch. Try to invision the plumbing system throughout, attempt to locate the main trunk as wither that, or a fairly long branch is not strapped very well. Inspect the toilet valves, maybe even shut the angle stops off. Turn the stop for the DW off too, If you can isolate the hammering with stops that will help determine exactly where it is. Personally I would use the arrestor as a last resort, or if it was a rental and I have a landlord barking at how much this is gonna cost. Which is one of the main reasons I stay away from them. If you get hammering no matter what you turn on and off, get a helper to continuously make it happen, and comb the property, feel the walls, and listen. 

Does it happen only when you turn the hot off with a sharp turn of a fixture or even when gradual? Have a look at the age of the washing machine too. Hope that helps a little!!


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## Ron The Plumber (Oct 10, 2006)

Mike Finley said:


> Say what? You can make ones out of copper that don't work forever and cover them up but factory made ones that work have to be accessable?


UPC Code 609.10.1 *Air Chambers*

Where air chambers are installed, they shall be in an accessible place, and each chamber shall be provided with an accessible means for restoring the air in the event that the chamber becomes waterlogged.


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## Ron The Plumber (Oct 10, 2006)

I don't think I have ever used arrestors in any residential application.


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## reveivl (May 29, 2005)

I recently got access to 'city water', I was previously on a well, and when I hooked it into the house I was required to install arrestors. I said 'why don't we wait and see if I have a problem before I fix it' but it is code, so in they went.


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## Double-A (Jul 3, 2006)

Mike, one more thing. Since the walls are open, and quite a bit of the 'hammer' you hear can come from improperly strapped pipes, grab the pipes and give them a shake. If they rattle in the wall, strap them down. Do this in all exposed areas and open areas that are bad and might need extra attention.

This might take 1/2 hour at the most to do the exposed areas. Now, start fiddling with the faucets again. Still happening? What does it sound like? Pipes hitting things or woodpecker drumming on the pipes?

If its a drumming, and not really a BANG, BANg, BAng, Bang, bang, then its most likely in the faucet or stop, toilet ballcock or dishwasher (if it happens only when you open or close a faucet, not while its running). You should work on faucets one side at a time (hot or cold), and with all other stops closed.

Having the dishwasher service stop open while doing this might mask that you have a weak solenoid valve there. If you get this noise and it seems to be only on the fixtures close to the dishwasher, and haven't shut down that valve, then you can chase this for a month and replace everything around it until you find the culprit. So turn it off as well.

A solenoid is basically a metal rod with a washer on one end, and a spring (to hold it closed), and an electromagnet (to open it) on the other end. If the spring is weak, the moving water will cause the washer to 'bounce' on its seat, usually in a drumming fashion. BBBRRRrAAAAaaaatttttt. Until you close the faucet and stop water flow.

Banging pipes, moving in the wall and hitting framing and structure are just that, bangers.

Listen to the noise and imagine the water moving in the pipes.


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## Ron The Plumber (Oct 10, 2006)

What is the water pressure on the house?


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## Mike Finley (Apr 28, 2004)

I'm guessing it is high, it seems high, and there is no sign of a pressure reducer anywhere. 

Ron, the arrestors I bought say they can be sealed up in a wall, they say put them in side ways, upside down any direction you want.


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## JamesNLA (Jun 2, 2006)

Mike Finley said:


> I'm guessing it is high, it seems high, and there is no sign of a pressure reducer anywhere.
> 
> Ron, the arrestors I bought say they can be sealed up in a wall, they say put them in side ways, upside down any direction you want.


If that code is only part of the UPC, and your area has an ammendment to that, than by code you can. Usually anything servicable cannot be concealed. Of the ones I have seen, they are not to be installed behind walls, don't mean you can't do it, just gotta check ur local code ammendments!


EDIT: you should know the pressure in the house, anything over 60-70 put a regulator on it....maybe that might help!


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## Ron The Plumber (Oct 10, 2006)

High pressure can be the source of the hammer, test it and find out.

Now only thing that can override a written code is the installation directions from the manufracturer.

But check your local codes. You can never take away from a code but it can be added to. If they say in can be inside walls, local code can still require them accessible.

I'd almost guess once you reduce the pressure, if in fact it's high, that will stop the hammer.


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## Mike Finley (Apr 28, 2004)

Any tricks to finding the pressure? I'm guessing a gauge on one of the laundry room washer shut-offs?


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## JamesNLA (Jun 2, 2006)

Mike Finley said:


> Any tricks to finding the pressure? I'm guessing a gauge on one of the laundry room washer shut-offs?


LOL....no tricks on that one Mike!

Every guy who either tinkers with plumbing or has 30 years in the trade should have AT LEAST 1 pressure gauge. I own 3 and I use them all. 

See if you can read a hose bib out front, that MAY be city pressure. Than read a bib out back, that will/should be house pressure. If there is a difference, there is a PRV. If no bibs are available, and you only have a bib thread gauge than yes, go to the washer (cold side). Let us know what you read


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