🔍 Key Concepts

• Refrigeration compressor crankcase temperature and why it should stay warmer than the evaporator • How liquid refrigerant migration or floodback affects the compressor crankcase and oil • The difference between shortage of refrigerant, excess oil, and superheat in terms of what gets to the compressor

💭 Think About

• Think about which condition would allow cold liquid refrigerant to reach or accumulate in the compressor crankcase instead of staying in the evaporator • Ask yourself: which option would most likely lower the crankcase temperature enough to cause sweating or frosting on the compressor housing? • Consider what high superheat means at the compressor inlet — would that give you more liquid or more vapor at the compressor?

✅ Before You Answer

• Verify which option would increase the likelihood of liquid refrigerant being present at or near the compressor crankcase • Check your understanding of superheat: it means the refrigerant is fully vapor plus extra heat — would that tend to frost the crankcase? • Eliminate any options that would more likely cause warm suction gas to enter the compressor rather than cold liquid or very cold vapor