My house has a basement and attic heat pump. The attic unit has two PVC pipes for the condensate. One is connected to the heat pump body, and one to the large pan under the heat pump. They run parallel almost horizontally (barely any slope at all) to the outside wall, and through it into the back side of a gutter. The two drain lines run all the way separately, and I can see that this provides redundancy in case of a clog. Incidentally, I have never seen any moisture in the pan. There is a leak in that gutter, with some staining of the fascia and soffit at the condensate pipes. At some time, the previous owner moved the refrigerant lines up to that heat pump from an exterior wall to an interior wall, with generous holes in the top plate, sole plate, and presumably the first floor header. I am expecting to divert those drains through the house to the basement drain, and seal the back side of the gutter. That raises 3 questions. 1) If I connect and send these down the interior wall as a single pipe/tubing, would it defy any code or good practices? Specifically, does connecting them to a single drain create a significant risk? 2) Should I use PVC pipe down the wall, or a roll of plastic tubing to avoid any joints? 3) Is there any reason to avoid sending the drain tubing or pipe down the same hole with the insulated (and uninsulated) refrigerant lines?