The foul gas passing from the chiller to the purge unit in a refrigeration system has only one shot at removing moisture and acid as it passes through the typically 1" core media filter dryer.Redi/Controls Inc.'s dual inline one-pass filter dryer provides 35 in. w.c, of specially blended desiccant. This extra-long column of desiccant cleans and hydrates the refrigerant in a single pass to near ARI-7000 specifications.