Water filters are used in refrigerators to remove chemicals and particulates from the water prior to use by the ice maker or the water dispenser. Because of its position in the water system, any new water filter has the potential to introduce air into the water line. This air will be pushed along by the flow of water when the dispenser paddle is pressed as it seeks to get out of the system. Once the air starts moving, it will continue to move, pushing any water along the way toward the dispenser outlet even if the dispenser paddle is not being pressed. Water will continue to flow, until the air pocket works its way out of the water line.

For this reason, if you follow the installation instructions that come with any water filter, it is advised you run about a gallon of water through the dispenser to not only remove charcoal dust, but to also purge the water lines of air. Use a large enough container because once it starts flowing, it isn't going to stop until that air bubble is out.