🔍 Key Concepts

• Oil circulation and settling in a refrigeration compressor after it stops • Effect of compressor operating temperature and run time on oil level readings • Role of crankcase heaters in preventing refrigerant migration into the oil

💭 Think About

• Think about what happens to oil and refrigerant inside the compressor immediately after shutdown versus after some time has passed. • Consider whether you want the oil to be foaming/mixed with refrigerant or calm and separated when you check the sight glass. • Ask yourself in which situation the oil in the crankcase is most likely to be at a stable, normal operating level rather than temporarily high or low.

✅ Before You Answer

• Verify which options describe the compressor after a steady, prolonged period of normal operation. • Check which choice avoids conditions where oil level might be distorted by foaming, refrigerant migration, or recent oil addition. • Confirm that the conditions chosen allow the oil to stabilize in the crankcase, not while levels are still changing rapidly.