To ensure proper oil return to the compressor, how should the suction line be pitched?

To ensure proper oil return to the compressor, the suction line should be pitched downward toward the compressor. This is essential because the refrigerant oil, which helps lubricate the compressor, tends to settle at the lowest points in the system. By having a downward slope in the suction line, any accumulated oil can effectively flow back to the compressor where it is needed.

If the line were pitched upward toward the compressor, oil could become trapped in the line, potentially leading to oil starvation in the compressor. A level line might not facilitate the movement of oil back to the compressor effectively, as there would be no gravitational force assisting in the return. Additionally, if the line were at a 90-degree angle, it could create pressure drops and hinder the oil from flowing back properly. Thus, the downward pitch is vital for ensuring the effective and reliable operation of the refrigeration system.