When servicing an open refrigeration system, is it necessary to replace the filter drier?

Replacing the filter drier when servicing an open refrigeration system is indeed necessary. This is because the filter drier's purpose is to remove moisture and contaminants from the refrigerant, which are critical for maintaining the system's functionality and longevity. In an open system, when components are replaced or during any service procedure that exposes the refrigerant circuit to the atmosphere, there is a significant risk of moisture contamination.

Moisture can lead to corrosion, reduced efficiency, and even compressor failure. Therefore, it is considered a best practice to replace the filter drier whenever the system is opened to ensure that all contaminants, including moisture, are removed, thereby maintaining the integrity of the refrigeration cycle. Although some options suggest specific conditions under which to replace the filter drier, the general rule is that it should always be replaced to minimize risks associated with moisture and dirt entering the system.