There may be a connection problem
- Check if the plug is inserted in the wall socket properly
The appliance may not be switched on
- AC4064/AC4065 and AC4054/AC4055: press the function selection button
- AC4062/AC4063 and AC4052/AC5053: press the on/off button
The particle filter (ESP filter), the gas filter (Zeolite filter) or the front panel may not be placed properly
- Reinsert the filters and reattach the front panel
If you have performed the above checks and the appliance still does not work, it may be malfunctioning. Unplug the appliance and take it to your Philips dealer or an authorized Philips service centre.