A few weeks ago when the washing machine was in the rinse cycle where it would open and close the valve quickly a few time in a row, I started hearing a banging sound. I typically am sitting in my office which is in-between the kitchen and wash room.

I originally thought the water hammer noise was coming from the wash room but after reproducing it a few times I found that it seems to be stemming from a small 1/4" tube under the sink that goes to a water filter.

the interesting part is before this water filter tube is a T that splits between the water filter tube and the cold sink faucet but only the water filter tube seems to be shaking. The banging I hear seems to be the tube hitting the cabinet door slightly when this happens.

I've heard of water hammer before where the PVC pipes move but should I be concerned about this tubing moving? I could probably just tie it in place to stop it but wasn't' sure if any water hammer that would cause that should be minimize by an arrestor on the washing machine.

I was also wondering if the air chambers above the washer somehow filled with water and I just need to drain the system.

Any suggestions or ideas would be greatly appreciated.

 

I think I eventually figured this out. It is a combination of the harsh repetitive start/stop of the LG HE front loading washers and I think my air chambers got waterlogged.

There are quite a few forums about these HE washers causing terrible water hammer and even a class action lawsuit. In my case though I don't remember it always doing this so I decided to drain and "recharge" the air chambers and it seems better. I may put an arrestor on the washing machine too if I can find a low profile one. I only have a few inches of clearance.

 

I'm guessing the machine is in a finished room as you can make your own arresters out of copper pipe. As you have found out..... they can become water logged.

 

You might also want to check your water pressure. I have found that slightly high water pressure can exaggerate a slight water hammer even with air chambers.

 

I need to get something to check the pressure but last time the inspector was out it was around 75 psi and it was happening around then.

Interesting idea to make my own arrestors. It seems tolerable for now but I'll likely try to implement some sort of extra arrestor to help because the start and stop cycle on my washer is pretty terrible. It cycles on and off quickly about 7 times in a row.

 

I believe 75 psi is a little on the high side, do you have a pressure reducing valve? If not, you may want to have one installed. Mine keeps the water pressure right at 50 psi. They are usually adjustable, but I never changed the factory setting on mine.