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.