TRY POURING IN SOME WHITE DISTILLED VINEGAR AND RUNNING IT. THE VINEGAR LOOSEN UP ANY SCALE AND JUNK. AFTER RUNNING UNIT FOR AWHILE, DRAIN OUT ANY REMAINING LIQUID AND ADD DISTILLED WATER OR FILTERED WATER. RUN UNIT AGAIN. THEN DRAIN OUT ANY LIQUID. NOW THE UNIT SHOULD WORK AS NORMAL. IN THE FUTURE, TRY USING DISTILLED WATER OR FILTERED WATER.

3 screws hold the chamber where the fan is located. You'll need a hexagon head to screw these 3 out, once you do have them out it pops off and you can pull the fan off the rotor and clean it. We've had ours for some time now and this was the first time it made a screeching noise and stopped rotating. This probably took around 45 minutes to resolve this.