🔍 Key Concepts

• Behavior of refrigerant dissolved in compressor oil when pressure suddenly drops • Conditions in the crankcase at compressor start‑up (pressure and agitation) • Purpose and effect of crankcase heaters in refrigeration systems

💭 Think About

• Think about what happens to any gas that is dissolved in a liquid when you suddenly lower the pressure around that liquid. • Ask yourself whether simple mechanical agitation alone is usually enough to create heavy foaming, or if another factor must be present. • Consider why manufacturers install crankcase heaters: is it to cause foaming, to prevent foaming, or is it unrelated to foaming?

✅ Before You Answer

• Verify which choice mentions a sudden pressure change in the crankcase and how that would affect refrigerant in the oil. • Check whether any option incorrectly claims the effect happens only with certain equipment (e.g., hermetic units or when heaters are used). • Confirm that the correct explanation should connect refrigerant leaving the oil with the observed foaming at start‑up.