DIAGNOSIS Dirty plasma wave plates burning off accumulated dust or a foreign object on the heating element of the pre-filter.
FIX Unplug immediately. Remove and thoroughly clean the plasma wave plates as described above. Also remove the washable pre-filter (carbon filter behind it) and inspect for melted plastic or debris. Wash the pre-filter in lukewarm water, air dry.
IF THAT DIDN'T WORK The smell may be from the actual plasma wave generator malfunctioning and producing excess ozone. Turn Plasma Wave mode OFF in the settings. If smell stops, the generator unit is faulty.
HEADS UP Run the unit on high fan speed for 15 minutes in a well-ventilated room after cleaning before reassessing the smell. Persistent electrical burning smell means stop use.