Water hammer from washing machine valve

[sotal]

We had a new washing machine which is fantastic and quiet but has a very fast solenoid, so it creates a bang in the pipes as it closes. When it starts a cycle it seems to do lots of small fills, so we get a repeated banging. For the first few minutes then less frequent ones for the rest.

Now the old one didn't make any noise from the pipes but during the replacement of the washing machine we were having an extension built and to try and address another issue I replaced an isolation valve with a full bore one. Other than that the pipework to the utility room stayed the same.

After a little reading I found that this is an issue with newer washing machines and the fix is to install a water arrestor. So I promptly purchased one and fitted it between the hose and the isolation valve that it connects to (not full bore from the look of it).

However after fitting it doesn't seem to have done anything at all! I don't need to do anything else with it do I?

The only other thing I can think to do is to partially close the isolation valve at the washing machine. Would this help? Could it cause any issues? Any other thoughts?

Thanks

 

[CBW]

Check for your pipes being clipped, first and foremost.

 

[RandomGrinch]

Same for me - I bought a hammer arrestor and it worked for a while, but the hammer was eventually too much for it!
Partially shutting (or more like partially opening) the isolation valve combined with the arrestor made a huge difference.
The wash performance of the machine isn't compromised either.

 

[sotal]

Check for your pipes being clipped, first and foremost.

Yes all clipped as far as I can see (90% could be seen) - the other 10% is original pipework that I would assume was clipped.

 

[sotal]

Same for me - I bought a hammer arrestor and it worked for a while, but the hammer was eventually too much for it!
Partially shutting (or more like partially opening) the isolation valve combined with the arrestor made a huge difference.
The wash performance of the machine isn't compromised either.

Thanks, I'll have a go at partially shutting the valve to see if it helps.

 

[RandomGrinch]

Oh sorry! I missed the part about fitting the arrestor between hose and isolator valve.
It should be fitted on the intake of the machine itself - as close as possible to the source of the hammer.
In my case I needed another rubber washer just to make sure the arrestor seated properly.
But again the isolator needed adjusting also.
I hope that helps.

 

[The Baker]

I had a customer with water hammer which developed some eight years after his house had new bathroom and toilets installed.

I installed a 20 litre potable expansion vessel on the cold feed to his combi in his attic.

My point is that the shock arrester may simply be just a bit too small for the job.

I just happened to have a 20 litre in stock at the time and the customer was happy with that.