Oil collected in an oil separator is generally returned to which component?

• A. The compressor
• B. The evaporator
• C. The condenser
• D. The oil sump

Answer: (A)

Oil separation focuses on getting lubrication back to the part that needs it—the compressor—while keeping oil out of the refrigerant stream that goes through the rest of the system. In operation, oil that isn’t properly separated tends to ride with the refrigerant vapor. The oil separator captures that oil and returns it to the compressor so it can be circulated through the bearings and crankcase for lubrication. Returning the oil to the compressor keeps the lubrication loop intact and prevents oil from circulating to the evaporator or condenser, where it would harm heat transfer and system performance. So the oil collected in an oil separator is generally returned to the compressor, typically into its crankcase oil sump to be reused.