The Sub-Zero PRO 48 refrigeration system features a water filtration system that supplies filtered water to the ice maker to produce great-tasting ice. The water filter cartridge is designed to last for up to one year of continuous use of the ice maker. The electronic control system monitors the life of the water filter cartridge and indicates when it needs to be replaced. An indicator that reads "REPLACE FILTER" will be visible on the left side exterior temperature display.

Although it is designed to last for up to one year of use, the actual life of the filter cartridge may vary with water supply conditions. Therefore, it is recommended that the filter cartridge is replaced when the "REPLACE FILTER" indicator is displayed or if the ice cubes become hollow or smaller.

IMPORTANT NOTE: If the unit has been turned off or the ice maker disabled for one month or longer, the water filter cartridge should be replaced once the unit and ice maker are back in operation.