Unvented central heating system sounds like kettle!

[TomMs]

Hi Dilalio, appreciate the comment. I understand without being on site it's difficult.
I wanted to avoid floors up!
So what we are thinking is it's pipe or "connector" in heating system and NOT the HW System.
Thanks

 

[TomMs]

Thanks Picasso, so it's floorboards up time. When I put my ear "Screwdriver" to the return pipe then it does sound the culprit but i can't be sure with noise travel!
Cheers

 

[dilalio]

Without rereading the whole thread again, to determine if this has been covered, but...

Did the noise manifest itself, over time or was it immediately following modifications to the system/plumbing in general?
What were those mods and where? Expose those areas that were previously uplifted and investigate runs/joints/hidden fittings. It may be that methods were used to speed up the additional works and keep costs down and through wear and tear, nuisance-free operation, at the time, has now deteriorated and produced anomalies!

 

[picasso]

Could this be the problem ?


//www.diynot.com/diy/threads/t...ed-cylinder-resonance-vibration-noise.272772/

 

[TomMs]

I have a radiator as a bypass between pump and motorised valves(airing cupboard) I thought enough? In loft I have an Ariston contract sti 125 HWT no visibility or mention (in manual) of bypass valve between flow and return to tank.
The extension CH flow and return travel up though loft. I noticed the return from the extension (6 rads) cuts into the return from HWT in loft. It's the first cut in to the return from the HWT. Next cut in to same return is in airing cupboard on first floor and then dissapearsmunder floor boards.
Could this cause pressure differential and then noise?
Would a non return valve or a gate valve between CH return cut in and return out of HWT be beneficial or is that a mad idea?