It is never normal to see ice in the summer anywhere on a heat pump or 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. 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 on a heat pump or air conditioner in the summer there most likely is a problem. Below is a list of possible causes.