First alert carbon monoxide detector 3 beeps

3 Beeps and a Pause: EMERGENCY. This type of chirp means that smoke has been detected in your home. You and your family need to evacuate and call 9-1-1 once safely outside. Low Battery or End-of-Life: This type of chirp indicates it is time to replace your smoke alarm's batteries or the smoke alarm itself.

While it's important to call 9-1-1 if your CO alarm is sounding continuously without stopping, a CO alarm that chirps every 30 seconds is not an emergency. It probably means your CO alarm has reached its end of life and should be replaced. CO alarms have a life expectancy of around seven years.

3 Chirps approx. every 20 seconds Off Off Condition: Sensor Trouble/Sensor End-of-Life Alarm. Recommendation: Reset the alarm. If this does not clear the problem, replace alarm.

Different Types of Beeps and Chirps: 4 Beeps and a Pause: EMERGENCY. This means that carbon monoxide has been detected in the area, you should move to fresh air and call 9-1-1. 1 Beep Every Minute: Low Battery. It is time to replace the batteries in your carbon monoxide detector. 5 Beeps Every Minute: End of Life.