Radiator not heating

[Bertharius]

I've had a large vertical radiator with new valves installed on a wall. All my other standard radiators heat up but this one only gets luke-warm. The thermostatic valve gets very hot but strangely, the inlet part of the radiator (right next to it) initially remains cool. I can feel the top part of the radiator gradually warming up slightly and eventually the whole radiator is warm, but only slightly. The thermostatic valve remains extremely hot. The lockshield valve is fully open and its outlet pipe eventually reaches the same low temperature as the radiator. What could be the problem?

 

[John.g]

Here is a similar recent thread which will, hopefully, give you some pointers.

Radiator not working

Hi All, I recently installed a radiator and it only seems to be Luke warm along the base whilst the rest is stone cold. I have repressurised the system and bled the radiator the thermostat is set to the max setting and the other valve is turned all the way anti clockwise ( I have also tried it...

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[cjg]

you have a air lock on the return pipe,