Rad - back panel hot, front panel cold

[Xave]

Fitted a double radiator in the summer to replace a single. The new rad has been relocated to under a window. Any reason why the back panel should get blazing hot but the front only luke warm?

Thanks

 

[chrishutt]

Have you vented all the air from the front panel (if the two panels have separate air vents)?

 

[Xave]

It just has the 1 bleed valve which does both sides - which ive bled

 

[chrishutt]

Could sludge from the system have got into the rad and blocked the channel to the front panel? Other than that I can't think of any possible explanation, unless there is a manufacturing defect.