When should liquid refrigerant be introduced into the system?

Introducing liquid refrigerant into the system is generally conducted under specific conditions to ensure the system operates correctly and safely. The correct scenario is when the system is under a vacuum condition or during the proper charging process.

When refrigerant is added while the system is in a vacuum, it ensures that there are no contaminants or moisture in the system, which can lead to inefficiencies or damage. A vacuum condition indicates that any air and moisture have been evacuated, allowing for a clean introduction of the liquid refrigerant. This practice helps maintain the integrity of the refrigerant charge and the efficiency of the system. Proper charging, where the system is filled with the correct amount of refrigerant, is crucial for its optimal performance and longevity.

In contrast, adding refrigerant when the system is off, during maintenance, or after reaching maximum pressure can lead to potential issues with system performance or safety. Each of these scenarios could introduce risks like overcharging or contamination, which impacts the functionality and effectiveness of the refrigeration system.