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Support for your Dyson Purifier Humidify+Cool Formaldehyde

Dyson Purifier Humidify+Cool Formaldehyde PH04 (White/Gold)

Activate your guarantee

You can receive support that's tailored to you, exclusive owner benefits and more when you register your machine.

Getting started

Watch our getting started video to help you get up and running quickly.

Dyson Purifier Humidify+Cool Formaldehyde ready to be assembled

Video Transcript

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Do more with the Dyson Link app

The Dyson Link app lets you monitor and control your purifying humidifying fan – wherever you are.¹ If you haven't already, download the app for more features and the latest updates.

Dyson Link app rated 4.4 out of 5 (average as of November 2020)

Connecting your machine

Follow these three simple steps to connect your machine to the Dyson Link app.¹

  • Step 1

    After you've downloaded the Dyson Link app,¹ open it and select 'Add machine' from the menu. Then select your machine.

  • Step 2

    Hold your mobile device next to your machine's display. This will allow your machine to detect your device.

  • Step 3

    Press the Standby button on your machine to activate the pairing process. Then follow the on-screen instructions to complete connection set up.

Using your machine

  • Watch how to use the Auto modes

    Video Transcript

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    Auto purify and humidify

    When both Auto modes are selected, your machine constantly monitors your air quality, automatically adjusting airflow to reach and maintain the most comfortable humidity level.

  • Watch how to use Airflow modes

    Video Transcript

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    Airflow modes

    You can use either your remote control or the Dyson Link app to change airflow modes. Choose between Fan mode, Diffused mode and Breeze mode. Watch the video to learn more about each airflow mode.

  • Watch how to use Night mode

    Video Transcript

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    Night mode

    For quiet times or when sleeping, turn on Night mode using your remote control or the Dyson Link app. Your machine will then use its quietest settings, with a dimmed display.

  • Watch how to use the Sleep timer

    Video Transcript

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    Sleep timer

    To turn your machine off automatically after a selected amount of time, press the Sleep timer button on your remote control or the Dyson Link app. Then select the amount of time you want your machine to run for.

Helpful tips for best performance

Using the Dyson Link app

  • App Home screen

    Set and forget

    View real-time or historic air quality data wherever you are, or set and forget with advance 7-day scheduling.

  • App controls

    Instant control

    Your primary controls are now instantly accessed on the home screen, including power, fan speed and temperature.

  • App Help section

    Help is at hand

    Not sure what NO₂ or VOCs are? Find instant answers and learn more about air quality in our app's help section.

  • App notifications

    Important notifications

    Receive helpful reminders when it's time to run a Deep clean cycle, or change your combination filter.

Understanding your LCD screen icons

The icons on the built-in-LCD screen show you which pollutants are present, reporting them in real time. They also tell you about humidity and filter life, and will alert you when it's time to run a Deep clean cycle.

  • Indoor Air Quality Index (AQI)

    Shows your air quality over the last 12 seconds, or over the last 24 hours. 

  • Formaldehyde (HCHO)

    Displays particles of formaldehyde, a volatile gas that can emit for years from household flooring and furniture. 

  • Particulate matter PM2.5

    Your machine is sensing microscopic particles smaller than 2.5 microns, including smoke, bacteria and allergens.

  • Particulate matter PM10

    Your machine is sensing particles smaller than 10 microns, including pollen, dust and pet dander.

  • Volatile Organic Compounds (VOCs)

    Your machine is detecting gases released from a wide range of sources, such as aerosol sprays and air fresheners. 

  • Nitrogen Dioxide (NO₂)

    Your machine is detecting oxidising gases such as NO₂ released by combustion. Includes cigarette smoke, candles and car emissions.

  • Indoor temperature

    Shows the room's temperature.

  • Relative humidity info screen

    Shows the current humidity level in your room.

  • Humidification dial

    Shows the current room humidity in grey, and the target humidity level in blue. 

  • Humidifying to 50% target

    Shows your machine is humidifying to reach the set 50% target.

  • Humidifying to Auto target

    Shows your machine is humidifying to reach the Auto target.

  • Humidification target met

    Shows your humidification target has been met. 

  • Humidification target lower than room humidity

    Shows your target humidity is less than the current room humidity.

  • Filter life

    Shows how much filter life remains on your combination filter, so you know when to replace it.

  • Evaporator status

    Indicates how soon a Deep clean cycle is required.

  • Refill tank

    Shows it's time to refill the water tank.

  • Wi-Fi

    Shows the current status of connection to the Wi-Fi network.

Understanding pollutant levels

When a pollutant causes the air quality to drop, the relevant icon will appear on the LCD screen. The coloured bar on the left of the screen will indicate how much of the pollutant is present, and will continually update as your machine purifies the air. 

  • Good

    When the green section of the coloured bar is highlighted, your machine is detecting a very low level of the type of pollutant. 

  • Fair

    When the yellow section of the coloured bar is highlighted, your machine is detecting a moderate level of the type of pollutant. 

  • Poor

    When the orange section of the coloured bar is highlighted, your machine is detecting a high level of the type of pollutant. 

Very poor

When the red section of the coloured bar is highlighted, your machine is detecting a very high level of the type of pollutant. 

Extremely poor

When the dark red section of the coloured bar is highlighted, your machine is detecting an extremely high level of the type of pollutant. 


When the purple section of the coloured bar is highlighted, your machine is detecting a severe level of the type of pollutant. 

Maintaining your machine

How to run a Deep clean cycle

The monthly Deep clean cycle removes mineral build up from your machine's water system. Your machine's LCD screen and the Dyson Link app will let you know when it's time. You'll need 150g of citric acid, then follow the steps in our video guide or user manual.

Play the video. How to maintain your machine.

Video Transcript

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Information icon

We recommend only using citric acid when running a Deep clean cycle. It's a safe, natural cleaning agent, and is widely available.

The cap on the water tank contains power connections. When you fill the tank or run a Deep clean cycle, make sure the cap is completely dry before refitting. 

It's quick and easy to run a Deep clean cycle

You can run a Deep clean cycle in nine simple steps. After pressing the Deep clean cycle button on the front of your machine, start by following steps one and two.

  • Remove the covers and water tank

    Push the shroud release buttons to remove the shrouds. The inner door will spring open. Push the water tank release buttons, slide the tank out of your machine, and unclip the cap.

  • Remove the evaporator

    Remove the evaporator from your machine, place it in the water tank and refit the cap.

Information icon

Follow steps three to nine- as shown on your water tanks sticker.

  • Prepare the cleaning solution

    Remove the cap and evaporator. Fill the water tank half-full with cold tap water. Add 150g of citric acid and agitate until dissolved. Place the evaporator back in the tank and fill to the Max level with cold water.

  • Secure clips and wipe excess water

    The cap contains power connections, so must be kept dry. If wet, wipe thoroughly with a dry cloth, and make sure the cap and connections are completely dry. Replace the cap and secure the cap clips. 

  • Start the Deep clean cycle

    Slide the water tank into your machine. When prompted by the LCD screen, press the Deep clean cycle button. The cycle starts and a countdown appears.

  • Remove the water tank

    When the LCD screen shows the Deep clean cycle is complete, push down the water tank release buttons. Slide the water tank out of the machine and carry to the sink.

  • Rinse the evaporator and water tank

    Unclip the cap, remove the evaporator and rinse under a cold tap. Wipe away excess water. Rinse the water tank under a cold tap. Wipe the inside of the tank to remove any excess solution or debris.

  • Fill the water tank with cold water

    Refill the tank to the Max level, wipe off any excess water and replace the cap.

  • Reinsert the evaporator and water tank

    Make sure the cap and connections are completely dry. Push the evaporator back into your machine, close the inner door and replace the filter covers. Slide the water tank back into your machine.

  • How to change your filter

    Find out how to monitor and replace your combination filter in our video guide.

  • How to replace your filter

    Video Transcript

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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.² 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.³

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 Diffused 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 Auto mode is enabled, AUTO will be illuminated on your machine's LCD display. When purifying the air, AUTO will be in white. When the air in the room is purified, it will turn green and your purifier will remain idle until pollutant levels rise.

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.



Replacement parts

¹Requires device to run app, Wi-Fi or mobile data, Bluetooth 4.0 support, and iOS version 10 or Android version 5 (or above). Standard data and messaging rates may apply.

²Source is from ‘humidex’ released by ‘Environment Agency, Canada’

³Based on fan speed 1.


The Dyson warranty

  • 'How to' videos

    To help you get the most from your machine. Quick and easy.

  • Helpful tips

    Tailored reminders that will keep your machine working at its best, for longer. 

  • Exclusive owner benefits

    Priority access to previews of new Dyson technology, events and offers. 

  • Expert advice. 6 days a week.

    Freephone and live chat. The right advice for your machine, from real Dyson people. 

  • Free Dyson parts

    Replacement parts if something goes wrong during your warranty period. 

  • Hassle-free replacement

    If we can’t repair your machine, we’ll replace it while it's under warranty.

We don’t stop caring about our machines once they’re yours. Activating your warranty allows us to give you a tailored, direct service for your machine. Even after your warranty has ended, we’ll still be on hand to help.