Check for air leaks.
Hi,Our 1,990 H410 had the same problem. We have the Grunert compressor.The box was far from being airtight: by simply passing your hand in front of any of the three doors you could notice how the cold air was leaking (and if air goes out it also gets in, increasing the amount of ice buildup)After complaining many times to the Hunter dealer, they proceeded to improve the sealing of the doors. They put self adherent compact foam stripes on all the contact edges. The sealing is not yet perfect, but now the refrigerator can be called as such(Before the name it deserved was a shoe box)Results: a MUCH better performance of the system. Now the freezer makes ice and we have to be careful no to frozen the lettuce on the fridge. We still have frost but much less. The Grunert proved to be powerful enough to do the job, the BIG problem is the poor sealing of the box. Downside: the top doors outstand a bit over the working surface, but is not very obvious.Hope this helps,RafaelMarinaclaraValencia