Locate the water filter cartridge cap in the front base grill. Remove the filter by rotating the cap counter clockwise so the handle is in a vertical position. Then pull straight out on the filter cap, remove the filter cartridge cap by sliding it off the end of the cartridge. Set aside the filter cap and DO NOT discard. Remove the new filter from any packaging. Remove the cover from the O rings. Place the filter cartridge cap that was set aside earlier on the new filter by sliding the cap onto the end. Align the ridge on the filter with the ridge on the cap to make certain it is centered. Hold the assembled cap and filter unit with the handle in the vertical position and push the new filter cartridge into the opening of the base grill until it stops, rotate the cartridge cap clockwise to a horizontal position.