HU-400BCA Display & Control panel

ION - Indicates that the ion function is on. Use the ion function to reduce bacteria and particles in the air.
HEATING - Indicates that the heating function is on. Use the heating function for a higher capacity and a better spread of mist. 

WATER SHORTAGE - The icon will be lit when the water tank is empty. Refill water tank.

AUTO - Indicates that auto mode is turned on. 
TEMPERATURE/HUMIDITY - Shows current temperature and humidity. 
TIMER - Shows remaining time if the timer is activated.