What is the purpose of an oil separator?

• A. To reduce moisture in the oil
• B. To capture oil and prevent it from traveling throughout the system
• C. To cool the oil before it enters the compressor
• D. To measure refrigerant purity

Answer: (B)

Oil separators remove the oil that’s carried by refrigerant vapor after it leaves the compressor, capturing that oil so it can be returned to the compressor rather than circulating with the refrigerant through the rest of the system. This keeps the compressor properly lubricated and prevents oil from migrating to components like the condenser or dryer, which can disrupt operation and efficiency. The correct statement describes this function directly: capturing oil and preventing it from traveling throughout the system.

Moisture removal is done by driers and desiccants, not the separator. Cooling the oil before it enters the compressor is handled by an oil cooler, not the separator. Measuring refrigerant purity is done with instruments designed for that purpose, not an oil separator.