Kaeser air dryer TA 11 clogged.

Hi, I have a problem with a air dryer of make Kaeser, makers type TA 11, it's clogged and now airflow through the heat exchanger, we suspected at first that it was clogged with ice but after been off for one week it's still clogged. Manufacturer suggest that we buy a new dryer...any ideas or suggestions of how to un-clog it?, we have tried to blow air through the outlet connection but without any sucesss. Any advice would be much appreciated! Best regards, Rikard