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Coway airmega 400 sensor

Cause 1 of 2The lens of the pollution sensor is dirty. Source: Troubleshooting, p. 25

First checkClean the pollution sensor.

Causes and checks

The lens of the pollution sensor is dirty. Source: Troubleshooting, p. 25
1. Clean the pollution sensor. See Clean the pollution sensor.
The level stays Very unhealthy after more than two hours of running, or stays Good for more than an hour in a polluted environment. Source: Troubleshooting, p. 25
1. Adjust the sensitivity of the pollution sensor. See Adjust the pollution sensor sensitivity.

Service

If the checks above do not clear it, contact Coway customer service: 1-800-285-0982, cowaymega.com. United States (warranty service, 8:00 am to 5:00 pm PT, Monday to Friday). Source: Limited Warranty, p. 28

Other Airmega 400 problems

No air comes out from the air outlet4 causes in the manual. First: the power plug is not connected.
Air speed from the air outlet is significantly lowThe filter cleaning or replacement cycle has passed.
A bad smell comes out from the air outletThe filter cleaning or replacement cycle has passed.

Sources

User Manual, Air Purifier 400S/400/300S/300 (English, French). Coway. Document 1216776, revision 003, 88 pages, en-US. cowaymega.com. Listed on the manufacturer's support page. Retrieved 13 November 2026.

Page numbers are the numbers printed in the manual. Where this page and the manual differ, follow the manual.

Applies to: AP-2015E (variant AP-2015E(SILVER_US)), AP-2015F (variant AP-2015F(SILVER_US)), AP-1515G, AP-1515H. United States.
Source: User Manual, Air Purifier 400S/400/300S/300 (English, French), 1216776 revision 003
Last verified: 13 November 2026
Handbook: Coway Airmega 400S, 400, 300S and 300 air purifiers in Air purifiers; all Coway handbooks