A carbon monoxide (CO) detector senses carbon monoxide levels in the air. The alarm will sound if carbon monoxide is detected. Depending on the brand and model of detector in your home, the device may have a reset button or automatically reset itself. The device should be reset after the alarm goes off, after the batteries have been changed or after you have tested the alarm to ensure it is working correctly. A carbon monoxide detector that automatically resets will do so within 10 minutes of any of these situations. In a detector that must be manually reset, you must press the reset button before the sensor will begin working.
Locate the reset button. The reset button is found on the front panel of the device. The location of the button on the front panel varies based on the brand and model of carbon monoxide detector.
Hold down the reset button for five to 10 seconds.
Release the reset button. The device will either beep, a light will light up to indicate the device is now working, or both.