Low-temperature (season) set - used for the operation of the air conditioner in cooling mode at low ambient temperatures (usually provided in the air conditioner as an optional feature). The kit includes: the controller of the outdoor unit fan motor, compressor crankcase heater and heater drain line.
In some series of inverter split systems this option is implemented in hardware and software, thus if there is a need to use the air conditioner in the winter for cooling, you must install only drain the heater.