ZD30 dehumidfier is a little over a year old. I use it in the basement. Last year it worked great. Since starting it this season it ices-up --- I didn't notice that last year. I cleaned the filter and brushed the fins in the front [fins were not dusty]. Still ices-up. I don't know where this part [see pic] connects behind the front grill. What is it? Where does it connect? Can you help? Thanks algable@hotmail.com