Exam Question

### (a) Ingress of Air into the Freon System
**Concept:** Air ingress refers to the entry of non-condensable gases (primarily nitrogen and oxygen from the atmosphere) into the closed refrigeration circuit. This is a critical issue as the system is designed to circulate only the refrigerant and a small amount of lubricating oil.
**Causes:**
* **Leaks on the Low-Pressure Side:** The most common cause. When the system's internal pressure (e.g., in the evaporator or suction line) drops below atmospheric pressure (due to low load, undercharge, or during shutdown), air can be drawn in through faulty seals, poor brazing joints, or cracks.