To avoid fractionation, blended refrigerants should be:

To avoid fractionation, blended refrigerants should be:

• A. Charged as a Vapor
• B. Heated before charging
• C. Charged as a Liquid
• D. Charged after partial evacuation

Answer: (C)

When a refrigerant blend is used, its components have different boiling points, so the mixture can separate during charging or operation (fractionation). To prevent that, the liquid form should be introduced into the system. Liquid charging delivers the refrigerant in the same overall composition as the charge, so the system ends up with the intended blend ratio. If you charge as a vapor, the more volatile components vaporize first, changing the composition and potentially harming performance and lubrication. Heating before charging or evacuating first don’t address the fundamental issue of keeping the blend’s ratio intact during charge, so they’re not the preferred method.

When a refrigerant blend is used, its components have different boiling points, so the mixture can separate during charging or operation (fractionation). To prevent that, the liquid form should be introduced into the system. Liquid charging delivers the refrigerant in the same overall composition as the charge, so the system ends up with the intended blend ratio. If you charge as a vapor, the more volatile components vaporize first, changing the composition and potentially harming performance and lubrication. Heating before charging or evacuating first don’t address the fundamental issue of keeping the blend’s ratio intact during charge, so they’re not the preferred method.