Troubleshooting My Philips Sonicare AirFloss makes a whistling sound If your Philips Sonicare AirFloss is making a whistling sound, follow our tips below on how you can fix this. Clean the reservoir vent There is a small vent in the reservoir door opening (where you put the water/mouthwash) to let air in as water is drawn out. If the vent is blocked, it will reduce and eventually stop the water flow. To clean the reservoir vent, follow the steps below: Take a damp/moist paper towel or cotton bud Wipe along the inside edge of the reservoir door opening, especially on the top area Rinse well with cold tap water and ensure that there is no debris/dust left Note: Ensure that there is no debris from the paper tower or cotton bud inside the reservoir area. Still have questions? Contact our Consumer Care Agents for further assistance or visit our support page. If the vent is blocked, you must clean it using the following steps: Use a piece of paper towel or a cotton swab. Moisten (not soak) the paper towel or cotton swab with water. Clean the vent by wiping along the inside edge of the reservoir opening, especially at the top of the opening closest to the nozzle end of the device. Also wipe along the outside of the inside edge of the reservoir door from the top of the door closest to the nozzle end of the device. Rinse thoroughly with cold water and ensure no debris is left, from the paper towel or cotton swab, in the reservoir or along the edge of the opening or the inside of the door. Be careful not to allow debris into the reservoir fill opening.