Washer Water Hammer Arrestor not enough?

[x6tr2ni]

I got a new washer for a few months now (http://www.sears.com/kenmore-4.3-cu...p-02641383000P?prdNo=5&blockNo=5&blockType=G5).

I've been have water hammer issues when the washer stops the flow of water to the machine. I've tried getting a new arrestor, thinking the issue was because of a very old arrestor, even tried doubling up, one at the washer valve and the other at the wall, but it doesn't seem to be stopping the noise, though it is less loud. Anyone have any advice on how to fix the issue?

I had a potentially silly thought while writing this, but could it be that I have the valve turn too high (currently fully open), and just need to tighten it and reduce the flow of water? Does reducing flow reduce pressure?

Thanks

 

[Reach4]

Partially closing the valve could make this get better. Water hammer occurs when the water is flowing along at some speed. Suddenly the water is stopped, and the momentum of the water continues. This is like driving at some speed and slam on the brakes. There is tire squealing and other sound. If you drive slower and slam on the brakes, there is not as much sound. By closing the valve some you make the water flow slower.

Another thing to consider is a bigger arrestor. Bigger ones are not easy to find AFAIK. If using ones with the garden hose thread, you could double up on them.

Just to confirm, water hammer is a single bang when a valve shuts off. If you hear a repeated machine gun sound from your plumbing, you have a different thing going on.

 

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[Jadnashua]

It sounds like the arrestor(s) you installed were recent and likely new, but they do wear out. The other thing that may be part of it is if your water pressure is excessive. Code generally requires the pressure in the home to be no more than 80psi. If yours is higher, an arrestor may not solve your problems until you tackle the high water pressure.

Closing the valve partially will do nothing to the pressure, but will limit the volume of water that can pass. Less water, less weight, less kinetic energy (or momentum), so yes, it could help. It would also take longer to fill the washing machine, and if it's on a timer verses sensing the level, it may not work as well. Most newer ones sense the level, and will keep things open until that is reached, but not all.