Hammer Arrestor Installation Help

Got banging when the dishwasher shuts off. Seems to be the only thing that causes the hammer.

Here's what I have under the kitchen sink:

View attachment 2010-12-30 compressed.jpg

Looks like a 3/8 down to a 1/2.

So, where to install the arrestor? Can I do this without any soldering? Also, the 1/2 copper tube to the dishwasher seems pretty stiff. Is it easy to bend?

There are some compression fitting arrestors http://www.siouxchief.com/Supply/Ar...ers/Water-Hammer-Arresters2/Mini-Rester.7R7YG . I'm not sure if there is one the proper size for the pipe you have...one of the pros would know. If you can use one of those compression versions, then you'd just cut out s section of pipe, and slip the arrestor in and tighten the compression fittings and be done. The things work best, the closer to the DW you can go.

jadnashua is referring to a model 660-TR0B hammer arrestor. This will work in your situation, but you will have to have some skills to make it work with your copper supply line, and you will have to be very delicate in the installation work so as to not break the adjacent connections. This hammer arrestor is the lest secure method, but will get the job done for a DIYer determined to do the job themselves. You may need to cut the existing copper dishwasher supply line and compress on a new ferrule if a leak develops while you are tightening up the connection (I would do this anyways just to be sure a problem doesn't develop down the line). And you must be careful moving the copper supply line as you can crimp it fairly easily.

Just replace the copper tube with a stainless steel braided dishwasher connector hose. The construction of it will "absorb" the shock and eliminate the hammer effect. An arrestor should be attacted AT the valve causing the effect, and that is not easily done with a dishwasher. Installing it at the shutoff valve, could be ineffective in suppressing the sound.

I like the idea of just replacing the supply line. But I've never installed a dishwasher. I was checking out the situation. The hole from under the sink is sealed with foam. Is it typically easy to get to the connection through this little hole? Looks like a blind job.

REmove the foam and the opening should be more than large enough for the connector on the hose to slide through it.

You can pick up an in-line hammer arrestor with compression ends.





I use this on dishwashers in line.
One side threads to the stop and the other takes the supply line to the dishwasher.

I ordered one of the arrestors, Terry. The one on the far right. Looks like it comes with plastic ferrules. So here's where I show my novice plumbing "skills":

Will the plastic ferrules work on the 3/8 copper pipe that runs to the dishwasher?
To do this, do I cut out a section of the pipe roughly the size of the arrestor T and replace that section with the arrestor? What is a good rule of thumb as to how much pipe to remove?

Thanks.

Well, just installed the arrestor. No need to run the DW yet so we'll see if it fixed the hammer later.

Easy to install. I just used a hacksaw to cut out a 1 1/4 in section (package had instructions) and used a file to smooth it. Didn't have a pipe cutter. It came with plastic and copper ferrules so of course I used the copper ones with the copper pipe. No leaks.

Thanks for the help.

Edit for results: Wow. This thing works great. No more hammer. Highly recommended. Easy for even a novice like me to install.