Silence feature: When CO reaches alarm levels the alarm will sound—repeating horn pattern: 4 beeps, a pause, 4 beeps, etc. Press and hold the Test/Silence button until the horn is silent. The initial Silence cycle will last approximately 4 minutes.
Recommendation: The CO alarm Silence Feature can be activated by pressing and releasing the Test/CO Silence button on the initiating alarm while in alarm condition. The alarm will remain silent for approx. 5 minutes (with the red LED blinking on approx. every 10 seconds), depending on the level of CO detected.
If the alarm keeps beeping with a fresh battery, it means it's nearing the end of its life and should be replaced as soon as possible. To stop the sound: Remove the old battery and wait 30 seconds to put in a new one. Match the positive end of the battery with the positive terminal.
What is important is that when an end-of-life signal is sounded, the CO alarm must be replaced. This is true if the unit is a standalone CO alarm, or in a combination unit with a smoke alarm.
First, look for a button called 'silence' or 'reset'. Hold this button down for 10 or more seconds. Release the button, and the LED lights should blink or turn back on. Your unit might also let out a singular beep.
Never ignore the sound of the alarm! If the alarm is sounding, pressing the Test/Hush button will terminate the alarm. If the CO condition that caused the alert in the first place continues, the alarm will reactivate.
Clear Residual Charge to Stop the Chirp
Open the cover and take out the battery. Press and hold the test button for 15-30 seconds. This will fully reset the smoke alarm and drain any charge left inside. Insert the new battery and close the battery compartment.
The chirp will not stop until the unit is powered off. You'll know that it is an end-of-life warning and not a low battery warning because replacing the batteries will not stop the chirp. The chirp will stop only when the alarm is powered off.
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. This type of chirp indicates it is time to replace your carbon monoxide alarm.
This may silence the alarm for a brief period, but it will reactivate if CO levels remain high.
Unfortunately, there is no way to turn the unit off from beeping when there is a low battery with the exception of taking it down and removing the batteries.
Do not unplug your alarm! A First Alert plug-in carbon monoxide alarm will only reset when it is receiving electricity. Press and hold the Test/Silence button for 5 seconds to quiet a plug-in alarm while ventilating. You may have to do this numerous times to give the alarm time to reset.
If you begin hearing a single beep or chirping noise every minute, this indicates that your battery is getting low. If your battery is getting low, you should replace it right away. You want to ensure that your detector is always working at maximum capacity in case a leak does occur.
False or nuisance alarms are when your smoke detector or CO alarm goes off, but there is no presence of smoke or carbon monoxide in your home. However, if your smoke or carbon monoxide detector sounds indicating an emergency and you are not certain it is a nuisance alarm, evacuate the home and call 9-1-1.
If your digital carbon monoxide alarm says “END” on the display, this means it has reached the end of its life and needs to be replaced. The alarm will also chirp 5 times per minute to let you know it's time for replacement.
Alarms manufactured from February 1, 2006 forward
When an alarm has reached the end of its life, it needs to be replaced to continue protecting your home.
CO alarm life span
All CO alarms produced after August 1, 2009, have an end-of-life warning notification that alerts the resident that the alarm should be replaced. The CO alarm will beep every 30 seconds or display ERR or END. If a CO alarm is at its end-of-life, replacing the battery will not stop the beep.
Here's a simple guide: Smoke alarms alert you with three beeps in a row. Carbon monoxide alarms alert you with four beeps. A single chirp means the battery is low or the detector should be replaced.
The SMART HUSHTM feature can be used repeatedly until the air has been cleared of the condition causing the alarm. Pushing the Test/Hush button on the alarm will end the temporarily desensitized period. If the smoke is not too dense, after ten minutes the alarm will return to normal operation.
A First Alert Carbon Monoxide Alarm cannot be reset using the test - silence button. To reset the alarm, the unit needs fresh air and time to burn the contamination off the sensor. Push and hold the silence button for 5 seconds to silence the alarm while contamination is being burned off the sensor.
1 Beep Every Minute: Low Battery. It is time to replace the batteries in your carbon monoxide alarm. 5 Beeps Every Minute: End of Life. This chirp means it is time to replace your carbon monoxide alarm.