Weird radiator issue.

[Cmcb]

Hi, wondering if I need to replace a radiator.
I have a 1400mm double rad in the living room. 10 mins after the heating goes on every other rad on the system is hot apart from this one. The weird thing is that the pipe to the rad is hot, the lockshield is hot and the first part of the rad, where the water enters and splits to each panel is hot, however, directly adjacent to this is warm at best and takes ages to match the temp of the inlet pipe.

I have taken the rad off and flushed it (twice), there was some sludge but then ran clear, including out of both bleed valve points.
Radiator has been bled, the system pressure is normal. Combi boiler closed loop system.
All the rads are about 12 years old, and I only notices this issues when the heating went on a month or so ago.
So, could there be something wrong with the radiator? Anyone ever seen this before?

Many thanks and any ideas appreciated.

Craig.

 

[CBW]

I would look at balancing first.

 

[Harry Bloomfield]

Your system perhaps needs to be balanced, so the flow to each radiator is more equal.

What happens if you close the valves to the other radiators and just leave the valves open to that one?

 

[Cmcb]

Brill, thanks. I will try and balance them tomorrow and let you know what happens.

 

[Cmcb]

Balanced and now sorted.
Also found another with a cold spot so flushed that too.

Many thanks for help and advice.

Craig.