I will have to ask next time I have it serviced. I have had the heat pump replaced twice in the 42 years I have lived here, and the blower replaced once, and it has been serviced twice a year and nobody has ever gone in the attic. The service guys all comment that everything is outside. All I know is it is an "over/under heat pump" Here is a photo after the old one was replace, and before the new one was installed. No refrigerant lines into the house, just the 220 electrical line, and the low voltage line for the thermostat. And a duct into the house and out of the house. My mini split DOES have a refrigerant line, a drain line, and a power line to the inside head unit.