Question 124Refrigeration & AC - Assistant Engineer

The correct answer is C) system secondary refrigerant to freeze. Charging a refrigeration system with HCFC-123 under a deep vacuum can cause the secondary refrigerant (typically a water-glycol mixture) to freeze. This is because the low pressure inside the system allows the boiling point of the secondary refrigerant to drop significantly, potentially causing it to freeze. Necessary precautions, such as ensuring the system is properly evacuated and the refrigerant is charged at the correct pressure, must be taken to prevent this from happening. The other options are incorrect because: A) the purge unit would not be affected by charging the system, B) air and moisture would not necessarily enter the receiver, and D) the rupture disk would not rupture solely due to the charging process under vacuum.