Diagnosis
Air is being pulled through a leak, often at a filter seal. The whine is the motor spinning without proper load.
How to Fix It
Check all filter seals and connections. Step sequence: 1. Ensure the HEPA filter on top of the dirty water tank is correctly seated and the blue gasket is clean. 2. Confirm the secondary filter is fully inserted and dry. 3. Check that the dirty water tank is clicked firmly into the main body, with no debris on the tank's seal. 4. Inspect the main body's air inlet for blockages.
If That Didn't Work
The HEPA filter may be damaged or missing. A torn filter or missing filter creates a massive air leak. Replace with an official Tineco HEPA filter.
Heads Up
Never operate the vacuum without both the HEPA filter and the secondary filter installed and dry. This will instantly damage the motor.