What causes ice to build up around the hole on a evaporator where the fan blades are, to the point where blades are scraping ice? Electric defrost, clear drain and clear coil. Called Señor tech and he stated defrost termination was going too long then he thought maybe it was too short. Any idea would be great, have 2 locations with this problem and I'm flipping a coin on which way I adjust defrost termination settings. Maybe that's not even the issue. Any input would be greatly appreciated.