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Support for your Dyson Purifier Humidify+Cool Formaldehyde

Dyson Purifier Humidify+Cool Formaldehyde™ PH04 (Nickel/Gold)

Frequently asked questions

How can Auto mode help me achieve the most comfortable humidity level?

The most comfortable humidity level varies depending on the temperature.4 In Auto mode, your machine constantly monitors air quality, automatically adjusting airflow to reach and maintain the most comfortable humidity level.

How often does the filter need to be changed?

The combination filter needs to be changed every 12 months, based on 12 hours’ use a day.

How long can my machine humidify for?

With a full tank, your machine can humidify continuously for up to 36 hours in fan mode 1.

Can I switch off humidification?

Yes. The machine works as a purifier humidifier fan, or just a purifier fan.

How often should I run a Deep clean cycle?

This depends on the water hardness where you live. The machine prompts you to run the cycle once a month in hard water areas. It prompts you less often in softer water areas. You can select your water hardness with the Dyson Link app.¹

Will the humidifier overheat if it runs out of water?

No. It has a sensor to detect if it’s out of water. The screen alerts you to refill your water tank when needed.

Can multiple app users share the same machine?

Yes, an unlimited number of app users can control a single machine. The machine will only ever choose the most recent update. For example, if more than one person was updating the scheduling, the most recent change will be the one the machine progresses with.

Where should I place my machine?

Your machine is engineered to purify and humidify single rooms, so you should use it where you spend the majority of your time at home. 


When placing the machine, make sure there's at least a few feet of clearance on all sides, so that the air can circulate effectively. Place away from radiators, draughts or air vents. Turn air conditioning off, and keep doors and windows closed during use. 

Should I change the fan speed for different times of the day?

If you need a quieter environment, set your machine to fan speeds 1-4, or consider selecting Night mode. Your machine will then use its quietest settings, with a dimmed display.

Should I change the fan settings in different seasons?

Increasing airflow will create a cooling effect using purified air, so you may find it beneficial to change your purifier's speed settings as the temperature changes. For personal cooling in summer, use settings 4-10. In colder periods, enable Backwards airflow mode. It projects air through the back of the machine, to avoid unwanted cooling.

Does the LCD display stay on throughout the night?

If you're concerned by the brightness of your purifier's LCD display, consider enabling Night mode using your remote control or the Dyson Link app. During operation, a small moon icon indicates that your purifier is on, but the main display turns off after 10 seconds to help avoid sleep disturbance.

How do I know when my purifier humidifier fan is in Auto mode?

If both Auto humidify and Auto purify mode are enabled, you will see two A icons at the top of your LCD screen.

How long should my machine be turned on for?

Your purifier humidifier fan's auto mode is designed to manage the air quality in your home without you having to operate the machine – so it's only on when it needs to be. If you or someone in your home suffer from allergies or respiratory illnesses, we particularly recommend using Auto mode.

Should I keep my windows open or closed?

Your purifier works most efficiently in a sealed environment – opening the windows can allow more pollutants to enter the air in your home, which means your machine will take longer to work.


3 Source is from ‘humidex’ released by ‘Environment Agency, Canada’

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