What indicates high low side pressure in a refrigeration system?

The correct answer indicates that an overcharge of refrigerant can lead to high low side pressure in a refrigeration system. When there is too much refrigerant in the system, it can cause the pressure on the low side to increase beyond normal levels. This occurs because the excess refrigerant cannot vaporize properly in the evaporator, resulting in a higher pressure reading.

Maintaining the right amount of refrigerant is critical for the system's optimal performance; too much refrigerant disrupts the balance, leading to inefficient cooling and potential system damage. Consequently, recognizing and addressing an overcharge situation is vital for ensuring proper system function and longevity.

The other options contribute to different issues within the refrigeration cycle but do not directly signify high low side pressure in the same context. Low airflow through the evaporator affects heat exchange and can lead to frosting or a loss of cooling efficiency but does not inherently cause high low side pressure. Compressor failure may result in various pressure readings depending on the failure mode, but it typically leads to lower pressures. A restricted expansion device can cause imbalances in the system, potentially leading to low side pressure issues of a different nature.