Ductless Cooling and Heating Systems. Reasons That Ice May Form On An Air Conditioning System. Dirt along the evaporator coil and Loss of refrigerant. Should the evaporator coil become covered with dust and dirt, it will reduce the ability of the coil to absorb heat from the air. When refrigerant is the most serious source of ice developing, since it can lead to the compressor overheating. Call us 877-770-3548.