Correct line sizing is imperative to optimize the performance of the system. Undersized lines will result in high pressure drops, diminished capacity, and increased power requirements. An oversized suction line will lead to poor oil return (as oil and refrigerant do not mix) and premature compressor changeouts.
When the capacity of the refrigeration system is reduced, it is usually because of a pressure drop in the refrigeration lines. Therefore, it is important to keep the refrigeration lines as short as possible, use as few fittings as practicable, and be especially careful not to kink the lines.