What is the role of an accumulator in the oil return path?

• A. They store liquid refrigerant.
• B. They filter refrigerant gas for contaminants.
• C. They reduce vibration in the refrigerant line.
• D. They separate oil from refrigerant and return oil to the compressor.

Answer: (D)

Maintaining lubrication by returning oil to the compressor is the primary role of the accumulator in the oil return path. In a refrigeration system, oil rides with the refrigerant as it circulates. The accumulator sits on the suction side and provides a space where oil can separate from the refrigerant gas. Liquid refrigerant collected there is kept from slugging the compressor, while the oil settles and drains back through an oil-return path to the compressor, ensuring the compressor stays properly lubricated. This separation and return help prevent oil buildup in the evaporator and keep the lubrication circuit functioning smoothly.

It isn’t mainly for storing liquid refrigerant (that’s a receiver), filtering the gas for contaminants, or reducing vibration in the line, so those functions aren’t the primary purpose of the accumulator in the oil return path.