boiler on minemum setting?

Radiators will get warm all over, a slight difference between input side and output, as it looses heat on it way across, that is what it is supposed to do, If warm at bottom cold at top, that is when they need bleeding. The 2 that stay cold, check valves, the inlet or outlet side might be closed, thermostatic valves easy to see if they are open, other types you will have to turn to find out. Same with the one that gets warm.

SD
December 2011