Hello! . In the "heat" function, the air conditioners work the other way as they do in cold mode. that is, the outdoor unit becomes the low pressure part, and as colleague Omorma said, it is normal to freeze a little. if inside it warms you well, it is not necessary to touch anything. Normally the equipment comes with a system that regulates the pressure of the outdoor unit (in the heat function) so that it does not freeze too much. Have a good day!