Flip the power switch to the "on" position and ensure it is plugged securely into a grounded, three-pronged outlet if you have no power to the unit.
Check your house fuse box for a blown fuse or circuit breaker panel for a tripped circuit if the air purifier won't turn on. Replace your fuse or circuit breaker with a time-delay version if your home uses regular fuses or circuit breakers.
Replace the filters if the indicator light on top comes on or the air doesn't seem to be as clean. Turn off the unit and unplug it, then push in the tabs located on the front grille and pull them off. Remove the filters, then replace the HEPA filter by following the arrows on the frame and replace the pre-filter by placing it on the tabs.
Telephone Whirlpool customer service at 1-800-253-1301 if your troubleshooting tips don't work and you require further assistance.