Refrigerant blends need to be charged as a liquid.

• A. True
• B. False
• C. Only when using certain systems
• D. It depends

Answer: (A)

Refrigerant blends are made of multiple components with different boiling points, so they can separate into different ratios as they change phase inside the system. If you charge a blend as a gas, the components tend to fractionate during evaporation and condensation, causing the actual refrigerant composition circulating through the compressor and evaporator to drift away from the rated mix. Introducing the blend as a liquid helps keep the overall composition close to what the system was designed for, preserving performance and reducing the risk of improper cooling or equipment issues. While some blends (azeotropes) are less prone to fractionation, the practical and widely used approach is to charge most blends as a liquid.