On Mon, 14 Jan 2008 05:44:04 -0800 (PST), JB
wrote:

2. 2 of the radiators have been really problematic, kitchen and spare
bedroom. They hardly get warm despite me having many attempts at
correctly balancing the rads. All rads upstairs close to the pump are
turned down almost fully and still heat up really quick. I've been
through most of the posts and FAQs on this too. When I switch all
other rads off and just keep these two on ONLY the spare bedroom rad
responds and really hots up. This has a TRV on the return (as the lsv
side gets hot first ???). The kitchen one only just warms a little
along the top and the return stays cold and has a TRV on it. I have
had both rads off the wall, flushed them (all clear) and both flow and
returns are clear of blockages. The kitchen rad fails to heat even
when its the ONLY one switched on. Mind blowing !!! The kitchen rad is
just new last week, flow and return seem blockage free and the flow
freely once the lsv and trv are opened without rad.


Apologies for this dumb suggestion, but have you bled the rads? The
kitchen rad failing to heat up sounds like an airlock