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What to Do if a Carbon Monoxide Alarm Say Error

Steve Brachmann

Carbon monoxide poisoning is a great concern for families living in homes with furnaces and other gas-powered appliances. Home installation of carbon monoxide alarms is recommended by the U.S. Consumer Product Safety Commission.

Carbon monoxide alarms may need to be replaced if displaying an error message.

Carbon monoxide alarms will display an error message if the internal wiring or sensory equipment is malfunctioning. If your alarm is displaying an error message, some troubleshooting procedures can tell you if the message is displaying incorrectly or if your unit needs to be replaced.

Low Battery vs. Error

Understand the difference between a low battery message and an error message on your carbon monoxide alarm. Failing to understand the message can lead to inappropriate action. For Kidde carbon monoxide alarm models with an LED indicator, a steadily lit LED means the alarm has an error; a blinking LED denotes a low battery. Kidde models with a digital display will read 'Err' when an error has occurred, or 'Lb' for low battery. FireAngel, another brand of carbon monoxide alarm, uses a chirp system to alert owners about problems. A single chirp is repeated every minute if the battery needs changing; if the alarm senses faulty wiring or circuitry, it will emit a double chirp every minute. Review your owner's manual about error messages if your alarm is of a different brand.


Clean the interior of your carbon monoxide alarm as a troubleshooting measure. Error messages may be produced erroneously if there is dust or dirt affecting the sensory equipment of your carbon monoxide alarm. Use a vacuum with a brush attachment at a low power level to gently suck dust away from your alarm. Do not use cleaning solutions on your alarm or expose the sensory equipment because this can introduce new environmental irritants or damage the equipment.


Press and hold your carbon monoxide alarm's reset button as another troubleshooting procedure. Holding the reset button will reset the carbon monoxide alarm's settings and should remove any incorrectly displaying error messages, lights or signals. If the error message or sound does not restart, then your carbon monoxide alarm is functioning properly.


Replace your carbon monoxide alarm if none of the previous troubleshooting procedures has removed the error message. The most likely culprit is a problem in the circuitry or the sensory equipment. Contact your carbon monoxide alarm's manufacturer to order a replacement model for your home. Contact your local recycling authority and ask them about electrical component recycling facilities or proper recycling procedures.