What is likely to be the issue if low suction and discharge pressure are found, but high superheat and partial frosting on the evaporator unit are present?

When low suction and discharge pressures are observed alongside high superheat and partial frosting on the evaporator unit, the scenario suggests that the system is undercharged with refrigerant. In a refrigeration system, the evaporator's role is to absorb heat from the environment, and this process requires a specific level of refrigerant to maintain optimal pressure and temperature differences.

High superheat occurs when the refrigerant vaporizes completely before it reaches the compressor. This situation indicates that not enough refrigerant is present in the evaporator to absorb the necessary heat, resulting in a high temperature of the refrigerant vapor. The partial frosting on the evaporator also points to inadequate refrigerant flow, as it can cause localized cooling and freezing in specific spots but not across the entire evaporator coil.

In contrast, if the system were overcharged, one would expect to see low superheat and possibly high discharge pressure, which would not align with the presented symptoms. A refrigerant leak would typically manifest as low pressures across the board but often shows signs such as oily residue or an inability to maintain charge. Lastly, compressor failure tends to create broader issues with system operation rather than specific low pressure and high superheat conditions.

Thus, the combination of low suction and discharge pressures, coupled