Odd water hammer/noise

[Burger]

Hello,

I have been looking at an ongoing issue with noise at a property. It only affects the bathroom/boiler. I have renewed the stopcock as it wasn’t turning the water off, the tap cartridges have been swapped out. The noise is only on the bath or basin when the hot water is ran. I have isolated other taps and wc cistern to rule those out, the noise is still there when boiler turn off on switch. Only conclusions I can see now are iso valves or flow turbine on boiler, but doesn’t make the noise downstairs - I’m currently swapping iso valves for full bore.

Boiler: Vaillant EcoTEC pro 28

Noise was there before stopcock change, intermittent noise, and seems to stop half turning iso valve.

I have taken a video, but it won’t upload? Something about the file extension.Mov?

EDIT: changed iso,valves and still doing it.
EDIT2: checked flow turbine and inlet filter, all good.

 

[EvilDrPorkChop]

Don't suppose they have a cheap bar shower? Had it before where the bar shower is mixing and back feeding into the hot, causing water hammer and other problems.

 

[Burger]

Don't suppose they have a cheap bar shower? Had it before where the bar shower is mixing and back feeding into the hot, causing water hammer and other problems.

Thanks Evil, but no shower is electric. I have isolated every single cold supply, even downstairs hot, and still the issue. All taps are individual and ceramic cartridge. Only possibilities now are new taps or the flow restrictor on the boiler. It didn’t seem to do it when I close the cold feed iso under boiler slightly, customer to monitor.

 

[EvilDrPorkChop]

Use the restrictor on the cold iso valve under boiler to restrict flow. Are they on a water meter? and what's pressure like.

 

[Burger]

Use the restrictor on the cold iso valve under boiler to restrict flow. Are they on a water meter? and what's pressure like.

No water meter, didn’t measure the pressure as I ran out of time.

 

[OffshoreGas]

Do you use pulsation dampers in domestic stuff?

You can just be unlucky and end up with pipe lengths/configurations that lead to resonance.

 

[Burger]

Do you use pulsation dampers in domestic stuff?

You can just be unlucky and end up with pipe lengths/configurations that lead to resonance.

Haven’t heard of them, but I’d say no?

 

[OffshoreGas]

Pulsation dampers are like accumulators but only about the size of a tennis ball/coke can. They are intended to smooth the vibration in the pipe.

The other thing that I’ve known cause vibration is too high fluid velocity in the pipe.

 

[Burger]

Pulsation dampers are like accumulators but only about the size of a tennis ball/coke can. They are intended to smooth the vibration in the pipe.

The other thing that I’ve known cause vibration is too high fluid velocity in the pipe.

It could be the latter, some is piped in 22mm then reduces to 15mm, strange how the kitchen doesn’t do it, and upstairs has only recently started. Boiler is 2008 model, so been in while,as has the bathroom.

 

[EvilDrPorkChop]

To me in situations you have to ask yourself really, what could have changed. And if the boiler and bathroom is still the same then I'd be looking at incoming pressure etc. I've fitted the mini expansions/arresters as above and they usually don't solve the issue.