LOUD Chattering noise from new NRVs fitted

[Jasper71]

I wondered if anyone can help, recently I had fitted new crosswater NRVs and thermostatic cartridge on my flush mounted Crosswater shower/bath control (3 knob type) and since fitting when running the shower there is a loud chattering noise audible from the wall in the adjacent room. I am pretty sure it is coming from the shower/bath control. After hearing the noise I re-fitted the old thermo cartridge and the noise is still there so I guess it's one of or both new NRVs.

I have connected crosswater who kindly sent me the new cartridge and NRVs and the only thing they can suggest at the moment is that one of the NRVS hasn't been fully opened.

If anyone can provide any thoughts before I get my plumber back it would be greatly appreciatted.

Thanks

 

[ALEC1]

insufficient pressure I would have thought...crosswater work best on high pressure systems....

 

[Jasper71]

Thanks Alec1, I only changed the existing crosswater NRVs and thermo cartridge with new from crosswater so not cant see how this may have changed the water pressure.

I have just dine some checks and the noise only occurs when the hot water is mixed and is not as prominent when turning the bath control on.

 

[Charnwood]

Why were the NRVs replaced?

 

[Jasper71]

Charnwood, the NRVs were replaced because we were losing hot water in the bathroom taps and shower and was advised by a plumber that this was because cold water was mixing with the hot water in the shower mixer. Once the NRVs were replaced this stopped but the 'chattering' noise started!