Grinding juddering noise

[stevebamford]

Hi all,

We've got a new system (Santon unvented, WBosch boiler) and have been experiencing a strange noise which occurs briefly when the hot tap is initially turned on.

I can only describe it as a grinding/juddering sound and it sounds as though its from the loft (where the cylinder/boiler are).

e.g. I turn on the bath taps in the morning, get a good flow of water for maybe half a second , then the juddering noise and the flow decreases significantly.

Any ideas ? I've asked the installer who seemed a bit stumped (he knew about hammering and squeaking but not grinding/juddering )

Cheers

Steve

 

[stevebamford]

Anyone ?

 

[daveaf]

has it always done this from new?

 

[stevebamford]

Yeah its always done it - system is only 4 months old

Seems to happen more if h/w not been used for a while e.g. first thing in morning ?

 

[daveaf]

Id be having a word with the guy who installed it then!!

 

[stevebamford]

yeah i did !

Problem is that is not reproducible. It often happens the first time the hot water is used after a period of non-use. but not always

and when he came to look at it, it happened once but then not again so he couldn't home in on what was causing it

He's coming abck this week but just wondered if anyone on here had any ideas ?