All air conditioning systems are designed and certified to work with specific indoor and outdoor units for maximum efficiency and performance. When changing from an older unit that used R22 refrigerant to a more efficient and environmentally friendly unit that uses 410 refrigerant, it is very important to change the pipes (line-set). This ensures that there is no non-condensable left in the system. This could run through the compressor and other major parts of the system and cause blockage, this may cause your system to freeze up, or possibly cause damages that is irreparable.