Water hammer/vibrations

[PhoenixServices]

After some advice guys. Don’t know if I’m barking up the wrong tree, got a property that I fitted a Worcester in a couple of years ago. All been fine until last year when the new owners complained of water vibrations.

The property had been empty before that. I fitted a shock arrestor and it seemed to cure it but it has now returned.

It’s only when you flush the toilet and run a tap at the same time.
Is it worth changing the fill valve on the toilet. Or do I need to re-pressurise the shock arrestor, if so what pressure?

Sorry it’s such a long post.

 

[oz-plumber]

Do the vibrations happen with both hot & cold water - assumed you fitted a combi boiler.
Or do they only occur when the cold water is being used.

Could be worth changing the inlet valve on the cistern to see if the rectifies the problem

 

[Watts]

Worn out diaphragm washer in fill valve usually causes water hammer