Philips AC4004 User Manual

Problem

Possible solution

The appliance doesn’t 

work.

You ignored the filter replacement lights. You did not replace a filter when 

the corresponding filter replacement light and the REPLACE FILTER light 

started flashing and did not respond when the appliance started to beep 

every 30 minutes after approx. 2 weeks. As a result, the appliance is now 

locked and you have to replace the filter and reset the appliance (see 

chapter ‘Filter replacement’) so that the appliance can provide healthy air 

again.

The AIR QUALITY lights 

keep flashing and the 

appliance does not work.

There is a problem with the air quality sensor of the appliance. Please 

contact the Philips Consumer Care Centre in your country (you find its 

phone number in the worldwide guarantee leaflet). If there is no Consumer 

Care Centre in your country, go to your local Philips dealer.

No air comes out of the 

air outlet

The appliance is not switched on. Put the plug in the wall socket and switch 

on the appliance.
The air quality is good and the auto mode is activated. In this case, the 

appliance stops operating automatically when the air is clean to save 

electricity.

The airflow that comes 

out of the air outlet is 

significantly weaker than 

before.

The pre-filter is dirty. Clean the pre-filter (see chapter ‘Cleaning’).

You haven’t removed all packaging material from the filters. Make sure that 

you have removed all packaging material.

The air quality does not 

improve, even though 

the appliance has been 

operating for a long time.

One of the filters has not been placed in the appliance. Make sure that 

all filters are properly installed in the following order, starting with the 

innermost filter: HEPA filter, activated carbon filter, multi-care filter (AC4004 

only), pre-filter. The multi-care filter (AC4004 only) has to be attached to 

the back of the pre-filter.
The air quality sensor is wet. The humidity level in your room is high and 

causes condensation. Make sure that the air quality sensor is clean and dry 

(see chapter ‘Cleaning’).
The room in which you run the appliance is larger than 30m², which is the 

maximum size at which this air purifier can operate effectively.

The AIR QUALITY 

light does not change 

colour even though 

the appliance has been 

operating for some time.

The air quality sensor is dirty. Clean the air quality sensor (see 

chapter ‘Cleaning’).

I need cleaner air because 

I have an allergy.

You can change the air quality sensor sensitivity (see chapter ‘Using the 

appliance’) to make the air purifier clean the air even better.

The appliance is extra 

loud.

You have not removed all packaging material from the filters. Make sure that 

you have removed all packaging material.

22