Genuine Daikin 1559017 Connection Pipe is the factory-formed connection pipe that links refrigerant components inside the unit, carrying the charge through the circuit along the route Daikin designed. When it is kinked, damaged, or corroded, the unit can lose refrigerant, lose output, or stop and start at odd times. A genuine pipe follows the run the way your Daikin expects, with the correct bends and fittings — where a non-genuine part can sit wrong or leak at the joints.