8 common Coway air purifier problems (and how to fix them)

A straightforward troubleshooting guide to keep your Coway running smoothly.
Updated on April 15, 2024
Written by
Amparo Lopez
Amparo is a staff writer for HouseFresh, having joined us in 2023. She is a sustainability advocate, holding degrees in communications, human-centered design and environmental policy. Her work has a focus on air pollution and climate change.

Coway is a South Korean brand that’s been in the purifying business since 1989. It began manufacturing water and air purifiers because the company believes “water and air are the most essential components of our life,” according to its website. They’re onto something, aren’t they?

When it comes to its air purifier, Coway has an ample portfolio of functional yet elegant units that have granted them several design awards. One of their latest air purifiers, the Airmega 150, is even sold in the MoMa’s Design Store

But its aesthetics don’t compromise the air purifiers’ performance. One of their insignia units, the Airmega AP 1512HH Mighth, is still a strong player among the air purifiers we’ve tested at HouseFresh. Another one of our favorites is the Airmega 300.

However, your Coway air purifier can eventually malfunction like any other appliance.

Luckily, Coway’s units have the user in mind and are easy to fix when they malfunction. Below are some issues you might face and how to troubleshoot and fix them.

Problem 1: My Coway air purifier won’t turn on

This is a fairly all-encompassing problem we may encounter with all sorts of home appliances.

Of course, we implore you to check if the unit is actually plugged in first.

If it is, then here are some things to consider checking:

❓Is the outlet working correctly? 

It’s more common than you think to have an old, faulty outlet that affects power output. Also, using a power strip with too many plugged devices could overcharge the circuits and damage your Airmega. Whenever possible, use a dedicated outlet for the unit.

❓Are the air purifier covers firmly closed?

As a safety precaution, the unit won’t turn on if any cover isn’t closed properly. Make sure it’s well-fastened. 

❓Is the power cord in good condition? 

Maybe a mischievous pet decided to chew on it. Or the cable was excessively bent or twisted for a while. Accidental tripping over it could also lead to wear and tear. 

Inspect the cord and check the sections where it attaches to the unit on one end and the plug on the other. If it’s damaged, you’ll probably need to replace it.

Problem 2: The unit keeps turning off by itself

Air purifiers keep our indoor air clean and free of any harmful pollutants. They’re designed to run continuously, so a unit that keeps turning off can be problematic and annoying. If your Coway Airmega is acting up like this, here are a few things to try out.

❓Is the ECO mode on?

In Smart or ECO mode, the unit will automatically turn off after its sensors detect constant healthy air quality. Coway units do this to reduce energy consumption; the time may vary from 10 to 30 minutes of good air quality, depending on the unit. Switch to a different program if you rather have the air purifier working constantly. 

Remember that some models have smart and eco modes combined. For example, the Coway Airmega 400 has no way to turn off eco mode while also keeping the unit on auto. 

❓Is the cover lid in place?

If the unit’s covers are loose for over two seconds, it’ll stop operating. Make sure the cover (or covers, depending on the model) is properly attached. 

❓Is the unit plugged into the correct power rating?

Your air purifier might randomly turn off if it’s receiving the wrong voltage from the outlet. Any values higher or lower than what the model is designed for will cause malfunctioning. Here’s a list of the Coway units and their rated voltage:

Coway Airmega modelPower supplyRated voltage
Coway Airmega AP-1216L120 V – 60 Hz55 W
Coway Airmega AP-1512HH120 V – 60 Hz77 W
Coway Airmega AP-1512HHS120 V – 60 Hz80 W
Coway Airmega 200M AP-1518R 120 V – 60 Hz82 W
Coway Airmega 150120 V – 60 Hz35 W
Coway Airmega 160120 V – 60 Hz35 W
Coway Airmega 230120 V – 60 Hz60 W
Coway Airmega 240120 V – 60 Hz60 W
Coway Airmega 250 / 250S 120 V – 60 Hz64 W
Coway Airmega 300 / 300S120 V – 60 Hz57 W 
Coway Airmega 400 / 400S120 V – 60 Hz66 W                
Coway Airmega ProX120 V – 60 Hz65 W
Coway Airmega Aim120 V – 60 Hz33 W

❓Is the air purifier overheating?

If your air purifier is warm or hot to the touch, it could be overheating. Clogged filters, wrong voltage, extreme weather conditions, blocked air intake or outlet, or placing the air purifier close to a heat source can all cause overheating.

  1. Turn off your Coway Airmega and unplug it. Let it cool off for a while until it’s no longer hot. 
  2. Check the filter to see if it needs replacement and clean the pre-filter.
  3. Make sure no obstructions are near the air intake or objects placed over the air outlet.
  4. Also, check for nearby heating sources and ensure the unit isn’t near one.
  5. Examine the power cord to see if it’s faulty.

If everything seems in order after a thorough inspection, plug the unit back in and run it for a while.

If the problem persists, contact Coway’s customer support center; there could be a problem with the engine or motherboard.   

Problem 3: My Coway is making unusual or loud noises

Your brand-new air purifier comes with filters wrapped in plastic to protect them. If you’ve never bought one before, you may not know this. That’s why this is our starting point:

❓Did you remove the filter’s packaging?

If you didn’t, it’s not the end of the world. According to Coway, one customer used their unit for a whole year without removing it. 

The drawn air hitting the plastic wrapping will make a loud noise, yes, and the polluted air won’t be able to pass through the filter for cleaning. But the good news is the solution is as simple as removing the wrapping and replacing the filter in the unit.

❓Did anything fall inside the unit?

Small objects that accidentally drop into the unit could make a rattling sound. Air purifiers have a fair share of slots and orifices where tiny items could easily fall in.

In particular, the Coway Airmega 300 and 400 have a widely spaced grid to cover the air outlet where something like a coin could easily slip through. The same can be said for the Coway AP-1512hh Mighty, which you can see below:

You can remove some grids or covers. Try to see if you can access any lodged items inside when you do so. If they’re out of reach, try vacuuming the air purifier thoroughly. If that doesn’t work, turn off and unplug the unit. Then, hold it upside down, gently wiggle it, and let gravity do the job.

❓Are the filters clogged? 

The pre-filter and filter trap airborne particles, dust, and other debris. As these accumulate, the unit’s motor works harder to draw air into the unit, making a louder sound than usual.

Remove the pre-filter to vacuum and then rinse. If it isn’t time to change the HEPA filter yet and you’d like to extend its lifespan a little longer, you can vacuum that, too, to remove dust buildup. 

Problem 4: There’s a red light on my air purifier that won’t turn off

The red lights are a reminder to take care of the filters. The red indicator will turn on when it’s time to replace the filters and/or wash the pre-filter. 

❓Do you need to change the filters?

Replacing Coway’s filters, either the Max2 Filter or the HEPA and odor filters, is a straightforward process. So is cleaning the pre-filter. 

The filter lifespan varies between models, but usually, the pre-filter needs cleaning every two to four weeks.

  1. First, switch the unit off and unplug it from the outlet.
  2. Next, remove the covers to access the pre-filter and filter compartment. 
  3. Take out the pre-filter. It’ll probably be full of dust and lint, so handle it gently. Vacuum and rinse it. Make sure it’s completely dry before replacing it in the unit. 
  4. Once you remove the pre-filter, you can access the HEPA and odor filter or the Max2 filter, depending on the unit. These are not washable or reusable. Dispose of them in a plastic bag.
  5. Now it’s time to put the new filters into your Coway Airmega. Remember to remove the plastic wrapping before doing so. 
  6. Lastly, reassemble the unit by putting the covers back in place. Make sure they’re firmly attached to the unit.

For more visual instructions, check out our videos on how to replace the Airmega AP-1512HH Mighty and Coway Airmega 300 filters.

❓Did you reset the filter indicator?

After replacing the filters, you’ll need to reset the indicators to turn off the red lights. Otherwise, the filter lifespan won’t be counted properly, and the red lights will stay on.

You can easily reset the filter status indicator by holding the button down for a few seconds. Make sure the air purifier is on for this step.

Problem 5: The air quality indicator light is stuck and won’t change color

Coway Airmegca air quality indicators change colors in real-time according to indoor air pollution levels. However, sometimes they may get stuck and not change even when you know the air quality varies in the environment. If that’s the case, there are a few things to consider: 

❓Does the sensor sensitivity need adjusting? 

New Coway Airmeg purifiers are set to the standard sensitivity. You may need to adjust the sensitivity if the unit notices no changes in the air quality after a few hours of running. The scale is the same in all Coway units:

  1. Sensitive
  2. Normal (default)
  3. Insensitive

The steps to modify the sensitivity vary depending on whether the unit has app support or not. If your air purifier is a smart model with app support, follow these steps:

  1. Open the Coway IoCare app and select the unit you want to adjust to AQi sensitivity.
  2. Go to the “Device Management” tab and select “Product Settings” at the end of the screen.
  3. Next, select “Smart Mode Sensitivity.” Once again, the option is at the bottom of the page.
  4. Finally, select the sensitivity of your choosing and hit Save.

For units without app support, the process varies between models, although it can be done by pressing and holding a combination of keys while the unit is running:

Coway Airmega ModelInstructions to adjust AQI 
Coway Airmega 230 / 240 / Icon1. Do a long hold on the Mode and Light buttons simultaneously. 
2. Press the Mode button to choose the desired sensor sensitivity once the speed indicator flashes.
3. Press the Mode and Light button simultaneously for at least two seconds. 
Coway Airmega 250 1. Hold down the Mode and Fan speed buttons simultaneously for at least two seconds. 
2. Press the Mode button to choose the desired sensitivity once the speed indicator blinks on the current sensor sensitivity. 
3. Press the Mode and Fan speed buttons simultaneously again for at least two seconds. 
Coway Airmega 400 / 3001. Press and hold the Light and Smart or Air speed / Mode buttons simultaneously. 
2. Press one of the air speeds to select the sensor’s sensitivity on the Airmega 400 or the Air speed / Mode button to navigate the different options on the Airmega 300. 
3. Hold down the Light and Smart or Air speed / Mode buttons simultaneously again. Once settings have been saved, the unit will produce a sound.
Coway Airmega 150 / 1601. Hold down the Power and Fan speed buttons simultaneously for at least two seconds. 
2. Press the Fan speed button to choose the desired sensor sensitivity once the fan speed indicator flashes.
3. Press the Power and Fan speed buttons simultaneously again for at least two seconds. 
Coway Airmega 1512HH / 200M / AP-1216L1. Do a long hold on the Ionizer button and Fan speed button simultaneously. 
2. Press the Fan speed button to choose the desired sensor sensitivity once the speed indicator flashes.
3. Press the Ionizer button and Fan speed buttons simultaneously one last time for at least two seconds. 

❓Do the sensors need cleaning?

All air purifiers with air quality sensors need periodic sensor maintenance, and Coways are no exception.

Simply access the sensors compartment and gently wipe out any accumulated dust or lint that could mess with the air quality readings and AQI light. Vacuum the socket and use a dry cotton swab or a soft brush to remove the debris from the lens and any hard-to-reach places. 

❓Is the air purifier appropriate for the size of your space?

Every air purifier has a specific air cleaning capacity. If placed in a room that’s too big, the unit may struggle to clean the air and be unable to achieve good air quality. 

Besides, overworking could lead to more severe damage to your air purifier. Find out what square footage your model is suited for in the list below: 

Coway Airmega ModelRoom Coverage
Coway Airmega AP-1216L330 sq. ft.
Coway Airmega AP-1512HH 361 sq. ft.
Coway Airmega AP-1512HHS361 sq. ft.
Coway Airmega 200M AP-1518R 361 sq. ft.
Coway Airmega 150214 sq. ft.
Coway Airmega 160214 sq. ft.
Coway Airmega 230403 sq. ft.
Coway Airmega 240403 sq. ft.
Coway Airmega 250 / 250S 465 sq. ft.
Coway Airmega 300 / 300S628 sq. ft.
Coway Airmega 400 / 400S1,560 sq. ft.
Coway Airmega Aim264 sq. ft.
Coway Airmega Icon324 sq. ft.
Coway Airmega ProX2,126 sq. ft.

Problem 6: There’s a weird smell coming from my Coway Airmega

❓Is the filter clogged?

If you don’t replace your dirty filter promptly, it can release a dusty odor as dirt, dust, and other particulates accumulate on the filter’s surface.

If an unpleasant smell comes out of your air purifier but the filter replacement indicator isn’t on, remove it from the unit and vacuum gently before putting it back. 

However, if you notice no change after vacuuming, replace the filter with a new one.

❓Did you let the pre-filter dry completely before placing it back?

A damp pre-filter could be the source of the foul smell from the unit. Remove and wash it gently with soap. 

Rinse thoroughly and let it air dry until any trace of moisture is gone. Then, put the pre-filter back onto the air purifier.

Problem 7: The airflow is weaker than it used to be

❓Do you need to replace the filter?

If you read this far, you may have noticed that a clogged filter is a common culprit behind several issues and malfunctions. 

As for airflow, a clogged filter with too much dirt and dust will affect the cleaning power of your air purifier, hindering its capacity to circulate clean air. 

On top of replacing the filters, if you’ve noticed a weaker airflow, it could be worth giving the whole air purifier a deep clean to boost its performance. You can find tips for that in our step-by-step guide.

❓Are there any blockages near the air intake?

Where you put your air purifier is important to optimize performance. Ideally, place it where it can draw the most air possible from the room, away from large objects, furniture, or walls.

Problem 8: The unit isn’t responding to the remote control from the IoCare app

❓Have you paired the unit to your phone? 

If you haven’t done this already, you won’t be able to interact with your Coway Airmega remotely through the IoCare app.

Follow these steps to pair your Coway air purifiers to your phone:

  1. Open the IoCare app and create an account if you haven’t already.
  2. Turn on your air purifier and select the “Register product” option.
  3. Scan the barcode on the back of your Coway Airmega. If you prefer not to grant the app access to your camera, you can type the code number manually.
  4. Android users only: turn off mobile data on your phone before the next step.
  5. Press and hold the Wi-Fi and Light buttons for over three seconds to activate the Wi-Fi configuration mode. The Wi-Fi LED light will blink, and you’ll hear a chime or beep. Press Next on the IoCare app.
  6. Wait for a second chime and press Next again; you’ll be asked to set a nickname for the unit and agree to the Wi-Fi connection.
  7. Select the network and type in your password. The Wi-Fi light will stay on the air purifier. That’s how you know you’ve paired your Coway Airmega with your phone.

Coway’s app pairing video guide is also very thorough and is useful if it’s your first time connecting your air purifier to your phone.

❓Is the unit connected to the right Wi-Fi frequency?

Nowadays, it’s common to have two bands on Wi-Fi home networks: 2.4GHz and 5GHz. Older Airmega air purifiers only support the 2.4GHz band, so your phone needs to be on that frequency when pairing the unit.

❓Is the Wi-Fi LED light on your air purifier?

A blinking Wi-Fi LED light indicates an issue with your internet connection. No light means the unit isn’t connected to the Wi-Fi network. 

To re-establish the connection, check that the router is on and that your home network is steady and running. Then, go to the IoCare app and recheck if the unit is still correctly paired to your mobile and home Wi-Fi. If not, follow the steps above to pair the devices.


Coway performs server upgrades occasionally. These updates could lead to your unit disconnecting from the Wi-Fi network and suddenly appearing offline on the IoCare app. There’s not much to do in such cases but wait for updates to finish.

Find your Coway air purifier manual

Manuals are underappreciated guides, forgotten until we need them. Let’s be honest, not many of us keep them around. If you ever need to reference information from your purifier’s manual, you can find digital links to them below:

Coway Airmega ModelLink to the user manual 
Coway Airmega AP-1216LUser manual
Coway Airmega AP-1512HHUser manual
Coway Airmega AP-1512HHSUser manual
Coway Airmega 200M AP-1518R User manual
Coway Airmega 150User manual
Coway Airmega 160User manual
Coway Airmega 230User manual
Coway Airmega 240User manual
Coway Airmega 250 / 250S User manual
Coway Airmega 300 / 300S / 400 / 400SUser manual
Coway Airmega AimUser manual
Coway Airmega Icon / IconSUser manual
Coway Airmega ProXUser manual

How to contact Coway customer service

Sometimes, air purifiers can malfunction beyond our skills to fix them. In such cases, it’s best to contact Coway directly. 

Coway offers a toll-free customer service center that you can reach at 1-800-285-0982 from Monday to Friday, 10 AM to 8 PM CST. 

If, like me, you prefer assistance via email, you can contact the company at info@cowaymega.com

Final thoughts

For first-time users, air purifiers may seem like complicated devices with a lot of buttons and settings. However, they’re quite straightforward once you understand them a bit more. 

Similar to any other appliance, air purifiers might occasionally malfunction. While some issues may be more complex and require customer support from professionals, more often than not, there’s an easy fix. Keeping your Coway Airmega running smoothly shouldn’t be a daunting task.


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About the author

Amparo Lopez

Amparo is a staff writer for HouseFresh, having joined us in 2023. She is a sustainability advocate, holding degrees in communications, human-centered design and environmental policy. Her work has a focus on air pollution and climate change.

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