I have just fitted a new radiator onto an existing open vented system running from a Glow-worm 30HXI boiler. The problem I have is that the flow pipe to the rad is getting warm but the return pipe isn't! What can I try to rectify this ?

Huw, October 2009

Its airlocked....try bleeding the radiator again - it could help if you turned some of the other rads off to increase the pressure. Failing that, turn off the rad valves, disconnect from rad - which will drain down- and open them again, one at a time, into a shallow tray. Reconnect them, open both slowly at the same time, rad bleed valve open.

John, October 2009