if you mean a radiator then it could be air which needs bleeding out
or one of the 2 valves is turned off or if it has a TRV fitted then the pin could be stuck in under the TRV head
www.gascentalheatinguk.info, January 2009
There is nothing you as an individual can do with this appliance. It requires the attention of a CORGI engineer. Legal requirement.
toots, January 2009
EP 3000 is the timer /programmer not the boiler but no matter...
Heater = Radiator (probably) but no matter...
Cold rad may need bleeding to let excess air out - Should have both valves open. If one valve TRV type then control pin may be stuck down - easy to fix.
Otherwise the available heat may be being used up by the other radiators. If so increase bolier stat a bit if you can, speed up the circulating pump a bit if you can.
If still not better, fully open the cold radiator's outlet valve and partially close the outlet (lock shield) valves on the warm radiators.
