🔍 Key Concepts

• Behavior of lubricating oil in multi-compressor systems • Effects of parallel operation on shared suction/discharge lines • What typical failure modes actually occur first in refrigeration systems (evaporator, TXV/expansion valve, condenser, or oil system)

💭 Think About

• Which of these components (evaporators, expansion valves, lubricating system, condenser) is most sensitive to small differences between two compressors running together? • If two compressors are not perfectly matched, what could flow from the higher-pressure crankcase to the lower-pressure crankcase? • Think about what is commonly equalized or carefully managed when a system is designed for parallel compressor operation.

✅ Before You Answer

• Identify which option involves crankcase pressures and oil circulation, not just refrigerant pressure • Ask: which failure would be gradual but serious, rather than an immediate dramatic failure like burst condensers or failed evaporators? • Verify which component normally has specific piping or equalizing lines when multiple compressors are intentionally run in parallel.