One radiator not heating up

[Scouse6]

I drained the system, put a new thermostat valve on and the radiator is just about warm. the rest of the system is very hot. The heating as been on all day. This radiator is not very old and we have had a new boiler fitted. The only thing i can think of is to redrain the system and take it off an d flush it through. The supply valve is very hot but the return valve is cold.
Any other advice...????

 

[EliteHeat]

Shut off all other radiators and force the heat through this one. You may find that after a lot of gushing noises it starts to work correctly.

 

[Scouse6]

Thanx for the prompt reply Eliteheat,
I take it you mean turn off both feed and return valves on all the other rediators and leave the cool one open both ends.
Then switch the boiler on and let it run like that for a little while...?????

Shut off all other radiators and force the heat through this one. You may find that after a lot of gushing noises it starts to work correctly.

 

[EliteHeat]

You only need to shut one end off to stop the flow, both ends fully open on the duff one.

 

[Scouse6]

That worked great , but I was wondering ,should I repeat the same thing, but this time open the drain cock and let the clap run out into the drain...???
I m worried about the crap just resetling.

Thanks again EliteHeat

 

[Scouse6]

Shut off all other radiators and force the heat through this one. You may find that after a lot of gushing noises it starts to work correctly.

This advice worked great, ever after 2 weeks its back tobeing cold. I took the radiator off, flushed it through replaced the valves. Still no use every few days I have to re peat Elite heats advice I notgice that most my pipes are half inch! but this rad is micro bore?? Could this be the problem...?????