Under normal operation, what is the state of refrigerant entering the compressor?

• A. High pressure vapor
• B. Liquid
• C. Low pressure superheated vapor
• D. Low pressure saturated liquid

Answer: (C)

The state entering the compressor is low‑pressure superheated vapor. In normal operation, the evaporator absorbs heat and turns the refrigerant into vapor at low pressure. A controlled amount of superheat is added so the refrigerant remains all vapor as it reaches the compressor, which protects the compressor from liquid slugging. After compression, the refrigerant becomes high‑pressure, high‑temperature vapor, which then goes to the condenser.

Why the other states don’t fit: high‑pressure vapor would be after compression, not at intake; liquid at the inlet would risk damaging the compressor; and a low‑pressure saturated liquid would indicate the refrigerant hasn’t fully vaporized in the evaporator.