upstairs radiators only heating up at bottom of radiator?

It is air that is causing your problem, but be advised that when you bleed them you will have to make sure that you top up the boiler pressure aswell. I always top up combis/condensers to about 1 to 1 1/2 bar.

Andy
March 2007

what boiler is it

hi-spec plumbing
March 2007

Is the pressure low on the dial?, if so top up with filling loop (silver braided pipe) below 2 bar, now try bleeding rads again. Water should weep out with no bubbles, recheck pressure, this should be about 1.5bar with all air out of system and cold. When running hot around 2 bar......
Hope this helps.

clfgas
March 2007