One cold radiator

[Den]

We have one cold radiator in a central heating system with a primatic cylinder (no header tank). We have flushed the radiator - worked for a short while. The radiator is cold even though the incoming pipe is hot. With left hand valve shut and right hand valve open, opening bleeding valve still produces water pressure and vice-versa. It has been suggested that we completely drain the system to remove any existing buildup of detritus. The radiator affected is furthest from the pump. Boiler has been kettling and Fernox additives have been successfully used via one of the radiators

Any suggestions will be gratefully received - we are looking forward to a warm room for our Christmas dinner (LOL).

[htg engineer]

Why/when did this happen, has it just happened or have you had the radiator removed for decorating ?

Check both valbes are open and try turning the other radiators off and see if this one heats up, check the pump setting and turn it up if possible.