On help with icing up is to make sure that there is plenty of air flow though the system. I used to close the vents if it got too cold. Now I simply raise the temp setting till it is comfortable. I also think that this keep the compressor from running as much. When it is 80DEG F in Seattle the temp setting may be as high as 77 or 78DEG. Bruce Romero "90 V8 brucer@pwi.com