Which of the following is a symptom of an overcharge?

The symptom of an overcharge that is indicated by low super heat is significant because superheat is the temperature of the refrigerant vapor above its saturation temperature at a given pressure. In an overcharged system, there is too much refrigerant circulating through the evaporator, which prevents the refrigerant from fully changing from a liquid to a vapor. As a result, the superheat reading decreases because the refrigerant does not absorb enough heat to complete the vaporization process.

When superheat is low, it often means that there is excess refrigerant in the evaporator coil, leading to liquid refrigerant potentially returning to the compressor, which can cause damaging situations like compressor failure. Correct levels of superheat are crucial for the efficient operation of the HVAC system, as they ensure that the refrigerant is evaporating properly to absorb heat before returning to the compressor.

High amp draw, high high side/low side pressure, and high subcooling can also occur in systems that are experiencing various other issues that might not exclusively be related to overcharging, so they are less definitive indicators when diagnosing this specific problem.