What is the purpose of the filter drier on an AC system?

• A. Removes moisture
• B. Removes odors
• C. Filters particulates
• D. Lubricates compressor

Answer: (A)

Moisture in the refrigerant is a major problem for an AC system. The filter drier contains desiccant material that absorbs water as the refrigerant flows through it, removing moisture from the vapor and liquid. This helps prevent moisture-related issues like acid formation, corrosion, and ice buildup at the metering device or evaporator. It also helps trap small particulates to protect components, but its main job is moisture removal. It doesn’t remove odors, and it doesn’t lubricate the compressor.