On Wed, 18 Jan 2012 20:59:06 +0000, AmateurRob wrote:
Problem is I get air in the (top) 2nd floor radiator and hence a cold
radiator eventually. I'm having to bleed it about every 2 days to keep
it from going cold. I understand this is air getting into the system
somewhere, so I've increased the pressure to 2.0bar to try to identify
leaks. I've found a few dodgy radiator tails and so sorted those out.

It might be a problem with the fill loop or the pressure relief valve -
have you checked for leaks there? Your setup might also have an automatic
air bleed valve as part of the system, and apparently these can sometimes
fail and start letting air in.

cheers

Jules