Actually, frost on the suction line only indicates that at the location where the frost is present, the suction line piping is below the dew point temperature of the surrounding ambient air and at or below 32°F. That’s it. It is neither an indication of a properly operating system nor a system defect.
The actual frequency and tasks performed will vary from system to system. However, here are some generic maintenance tasks which can be applied to many refrigeration systems. These tasks can be divided into two groups: one for maintaining the cabinet and one for maintaining the refrigeration system.
Mechanical refrigeration is accomplished by continuously circulating, evaporating, and condensing a fixed supply of refrigerant in a closed system. This article describes and illustrates the basics of the refrigeration cycle.