It is never normal to see ice during the summer anywhere on the inside or outside of a heat pump or a central air conditioner. This includes the indoor unit, outdoor unit and interconnecting line-set. It is possible to ice-up the indoor coil however, if the air conditioner is running in very cold weather or if the thermostat is turned down extremely low. We recommend never turning the thermostat below 70 degrees when running your air conditioning. This could potentially cause your indoor coil to frost or even freeze up, and/or possibly cause your ductwork to sweat, which could lead to water or mold damage in your walls or ceilings. If air conditioning is needed during winter months, such as for restaurants or businesses, then a "Low ambient kit" is required, and can be installed by a service technician. If you see ice anywhere on a heat pump or air conditioner during the summer, then there is most likely a problem and you should turn it off immediately. Bad indoor fan motor- not running/running slow