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 (where you put water/mouthwash) opening to let air in as water is drawn out. If the vent is blocked, it will reduced and eventually stop the water flow. To clean the reservoir vent, follow the steps below: Take a damp/moist paper tower or cotton swab 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 are no debris/dust left Note: Ensure that there are no debris from paper tower or cotton swab inside the reservoir area. Still have questions? Contact our Consumer Care Agents for further assistance or visit our support page.