Mixer shower whistling

[nellystew]

The Triton Exe bar mixer shower I've just fitted is making a weird squealing/whistling noise, it's fed by a combi boiler.
I used the new hose and shower head

I've worked out (I think!) that it's to do with the hot water.
The noise gets worse the hotter I make the shower, and goes away if I make the shower very cold or run the basin hot water tap (even a little bit).

I sort of fixed it by changing the head back to the old one, but the noise still happens occasionaly.

Is there anything else I can do to stop it?

 

[Madrab]

It's certainly one of the valves chattering, usually because of pressure - either the flow valve is getting worn and needs replacing or it's the thermo valve getting tired. How old is the shower?

Do you have really good water pressure?

 

[nellystew]

The mixer is brand new.

I bought a pressure tester, it’s about 3.4 bar, measured from the outside tap.

 

[dilalio]

Put a reducing valve in and maybe a shock arrestor.

 

[Madrab]

If it's brand new I'd be tempted to send your vid to Triton and ask their advice. It's almost definitely a valve noise and it certainly shouldn't be making that noise out of the box. Wouldn't be the first time an item has shipped faulty.

 

[dilalio]

it's fed by a combi boiler.

With 3.4 bar incoming mains you need a PRV and a shock arrestor as most/if not all combi MI's state. And benchmarks.