Press and hold the test button on the CO detector
Confirm the alarm sounds and any indicator lights activate
Check the display for a test result or battery status if available
Use a manufacturer-approved CO test gas if you want to verify sensor response
Follow the detector’s manual for the correct test procedure
Test the detector monthly
Test after replacing batteries
Test after power outages if it is hardwired
Replace the detector if it fails to alarm during testing
Replace batteries if the low-battery indicator is on
Replace the detector at the end of its recommended service life