living room rad no longer gets hot

[bhm1712]

Before i begin:

Glow worm space saver mk2, Wilo Gold pump, open vent system ,gravity hot water. Upstairs CH pipes 22mm, downstairs MicroBore pipes with twin entry valves.

my living room rad which is on a twin entry valve and micropipes no longer gets hot, only luke warm. nothing has been altered on the system since it worked fine. i have bled the rad but water comes right out, no air.

any ideas? i have felt the flow pipe and this also seems only luke warm.

 

[bhm1712]

i wondered whether the system needs balancing, but it must have been balanced before and seeing as though nothing has been touched it cant have changed can it?

i just find it strange that as far as i know it is the last radiator on the system, and it appears as though its not getting hot water, however the return pipe at the boiler is alot hotter than the living room pipes

 

[bhm1712]

i have discovered that the lock shield valve is on the flow pipe, and the control valve on the return pipe