What is a Refrigerant Filter Drier?

The purpose of a refrigerant drier is to ensure the refrigerant system stays clean and dry. It removes contaminants including moisture, dirt, acid and solder flux, beads and filings. Whenever the refrigerant system is opened for repair or to replace a component, always replace the filter drier.

When replacing the liquid line filter drier, make sure the replacement size equals the size of your system and refrigerant line connections. It’s possible that in an older system someone might have replaced a drier at some time…and used the wrong size drier. So it’s a good practice to match the filter drier to the system size. Also, make sure the replacement drier is compatible with the system refrigerant. Always place the drier in the refrigerant circuit with the filter’s arrow pointing in the direction of refrigerant flow. If you are replacing a burned out compressor, install a suction filter designed for high acid content and follow good industry practices. If you are the technician performing the replacement, make a note detailing the date and the system operating characteristics including the pressure drop across the suction filter. This way you can follow up in a few days to check, remove and or replace the suction filter.