Hi All,
I'm new to this group and after some advice please.
My boiler has started to drip. I've taken off the front and have
located where the dripping water is coming from. I have a Potterton
Combi Performa 28... And the leaking part is best described as

http://www.potterton.co.uk/products/literature/Potterton_Performa.pdf#search='fixing%20potterton% 20performa%2028'

(Page 5)
I look at the 3 way valve assembly, and there's a brass-material like
thing that looks a bit like a brass round clock face behind it. The
leak is coming from the nut on the outside/middle of this, but it looks
as though there's a tiny little hole in it anyway which I'm presuming
should be there.

Any suggestions what the problem could be please?

Thanks, Jon.