Very mild but annoying 'water hammer' in toilet cistern fill valve?

[JamesB1976]

Okay, I admit up-front this is a tad feeble, but I'd rather ask the question than expend more effort and money (immediately at least). I recently replaced the siphon in my concealed bathroom toilet cistern after the diaphragm washer started to go. As well as fitting a Dudley Turbo 88 siphon (no more total disassembly next time) I also replaced the traditional float-arm fill valve with a Dudley 'Hyroflo'.

Only after reconstructing the panelling etc. did I start to notice a weird noise coming from the cistern: when either the sink or bath cold taps are shut off and the cistern is full the Hydroflo valve briefly makes a strange 'fluttering' sound. A bit of reading seems to support my initial assumption that the new fill valve is much more sensitive, and is reacting to a pressure pulse caused by shutting off the tap(s) a.k.a water hammer. So to the question: would a small water hammer arrestor on the feed pipe to the cistern fix this? This is a long way from banging pipework and I'm concerned that there may be a threshold to how effective these things are, such that in my case it may make no difference?

 

[Newboy]

Did you fit the flow restrictor into the floatvalve tail?

 

[JamesB1976]

As this cistern has always filled quite slowly compared to downstairs, I removed the flow restrictor when fitting the new fill valve.....

 

[Newboy]

try fitting the flow restrictor and see if that resolves the issues without compromising the fill time too much.

To be honest, I'm not a fan of the Torbeck types - they are very easily clogged with debris.

I'd go Fluidmaster given the choice
https://www.screwfix.com/p/fluidmaster-bottom-entry-brass-shank-fill-valve/47792
https://www.screwfix.com/p/fluidmaster-side-entry-brass-shank-side-entry-fill-valve/49088