- Square Panasonic display: press the mode button to unlock the screen then hold down the 0 button for about 10 seconds to reset
- If that doesn't work, remove the front cover. Looking directly into the unit, you should see a labeled reset button on the back wall of the cabinet, approximately in the center. Press and hold this button for 10 seconds while unit is powered on.
- Black rectangular display: press and hold the middle (minus) button for about 10 seconds until "filter reset" shows on the screen