Which of the problems listed could be...

🔍 Key Concepts

• Refrigerant sight glass purpose – what does seeing clear liquid vs. bubbles usually tell you about system condition? • Refrigerant charge level – how does low refrigerant affect what you see in the liquid line? • Normal vs. abnormal conditions that could cause bubbles besides charge, such as excessive pressure drop or component malfunction.

💭 Think About

• Ask yourself: In a properly charged, normally operating system, what should the liquid line sight glass look like? • Which of these options would most directly cause vapor to appear in a line that is supposed to be carrying subcooled liquid? • Consider which options describe a condition (charge level) versus a specific component problem, and which would most consistently show up as continuous bubbles in the sight glass.

✅ Before You Answer

• Verify how a properly charged liquid line appears in the sight glass under normal load: clear or bubbly? • Check your understanding of insufficient refrigerant: does it tend to introduce vapor into the liquid line and sight glass? • Consider whether a faulty expansion valve or solenoid valve stuck open would necessarily and directly create bubbles in the liquid line sight glass, or if their effects are seen elsewhere.

Which of the problems listed could be indicated if a sight glass in the refrigerant liquid line is full of bubbles?

Proper refrigerant charge

Faulty expansion valve

Insufficient refrigerant

Solenoid valve stuck open

🔍 Key Concepts

💭 Think About

✅ Before You Answer