filter drier

A filter-drier (or filter dryer) is a component in refrigeration and air conditioning systems that removes contaminants like moisture, dirt, and acid from the refrigerant. It typically consists of a molecular sieve for moisture absorption and a filter for trapping particles, protecting the compressor and the system from damage. They are a critical part of the system's reliability and are replaced whenever the system is opened, or if there's excessive pressure drop, indicating a blockage.