Scandinova freezer not reaching correct temperature

[rickmacc]

I have a scandinova up right freezer model UF 7-87W. It has got indicator lights on it to tell you when it has reached correct temp. its not reaching correct temp ie -18. It is only reaching -11. I have defrosted it because i thought that was the fault because there was a build up of ice at the top.
The compressor is running at back but it is very warm. the door seems to be closing ok seal on door looks ok, could door seal be leaking

Any ideas

 

[jayzee]

Look around the back you will see black mesh grille, is this covered in dust & fluff If so clean it off.I assume youve tried turning up the temp setting.

 

[racket]

If there is only ice in one place and the door seal is OK then it's short of refrigerant

Bin it