No, a grinding noise is not normal and usually means something is interfering with the fan.
- First, turn the unit off and unplug it from the wall for safety.
- Open the front grille and remove the filter. Check for any loose debris, like a piece of plastic wrap, paper, or a large dust bunny that got sucked in.
- While the filter is out, gently spin the fan blade by hand. It should move smoothly and quietly. If it's stiff, catches, or makes noise, the fan motor bearing is likely damaged.
- Reinstall the filter securely, making sure it's seated flat and not crooked.
IF THAT DIDN'T WORK: If the noise persists after clearing debris and reseating the filter, the internal fan assembly is faulty. The unit needs service.
HEADS UP: Running it with a grinding noise can worsen the damage. Stop using it until the cause is found and fixed.