One cold rad

[gallagher86]

I have a gravity feed heating system. F&E tank in the loft - boiler is located outside in the shed. the problem i am having is that when i turn on the heating on 1 radiator upstairs in the master bedroom wont get hot - I've bled the rad and its running clear water. if i isolate the heating down stairs and send all the heat upstairs that rad in question gets hot? there's no pressure guages anywhere so i can't tell if theres an issue with pressure although it's being fed from the F&E so this shouldn't be an issue.... anyone got any ideas on what the problem is? thanks

 

[ShaunCorbs]

System needs balancing we have a thread on how to balance them if you use the search box