How do I know if my carbon monoxide detector has a low battery?

Author: Alda Muller  |  Last update: Thursday, June 19, 2025

Carbon monoxide alarms alert you with four beeps. A single chirp means the battery is low or the detector should be replaced.

How to tell if a carbon monoxide detector needs a new battery?

When the CO alarm emits a quick beep every 30 seconds and the red LED flashes, you may need to change the batteries. Replace the batteries in the alarm. If the alarm continues to emit a quick beep every 30 seconds and the red LED flashes, the alarm has reached the end-of-life.

Can a low battery make a carbon monoxide alarm go off?

Yes the detector can go off for low battery voltage so make sure you have good DC voltage. IF the DC voltage is good and you are not smelling anything near the detector in the cabinets then very possible the detector is faulty giving out a false alarm.

What color should my carbon monoxide detector blink?

On First Alert carbon monoxide alarms, the red light flashes to show the CO alarm is properly receiving battery power. If you do not see the red light flashing, change the batteries in the alarm immediately.

How do I know if my carbon monoxide detector is working properly?

To test your carbon monoxide detectors, press and hold the test button on the alarm. The detector will sound 4 beeps, a pause, then 4 beeps for 5-6 seconds. Refer to the user manual for your specific model.

Recognising your carbon monoxide alarm warnings

What if the carbon monoxide alarm goes off but no fire?

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.

What do 4 beeps on a carbon monoxide detector mean?

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.

What can falsely set off a carbon monoxide detector?

Common causes of false alarms of carbon monoxide:
  • Close to cooking sources (10 feet minimum)
  • Close to sources of humidity (10-20 feet)
  • Near fireplaces.
  • Near water heaters.
  • Near furnaces.
  • Located in a poorly ventilated location like a garage, kitchen, or closet.

What are two warning signs of carbon monoxide poisoning?

The most common symptoms of CO poisoning are headache, dizziness, weakness, upset stomach, vomiting, chest pain, and confusion. CO symptoms are often described as “flu-like.” If you breathe in a lot of CO, it can make you pass out or kill you.

Will a new battery in a carbon monoxide detector still beep?

The chirping sound usually indicates the alarm is near its end of life and requires replacing. Carbon monoxide detectors have a seven-year lifespan. Replacing the battery does not stop this type of beeping. Detectors that plug into a wall socket may have a loose battery when these types of beeps occur.

What if a carbon monoxide detector goes off and then stops?

If you have a carbon monoxide detector chirping and then it stops, it's important to take the situation seriously, even if the alarm is no longer sounding. Even if the alarm has stopped, get everyone out of the home to a place with fresh air. Contact 911 or your local fire department to report the incident.

How to tell if carbon monoxide is in the air?

The best way to alert you and your family to unsafe levels of CO is to install a carbon monoxide detector. It works like a smoke alarm, sampling the air in your home and creating a loud alarm when levels of the gas are detected. It's important to evacuate your home immediately when your CO alarm sounds.

Does a carbon monoxide alarm sound continuously?

A CO alarm that beeps continuously without stopping could indicate that carbon monoxide is present. If you your CO alarm is sounding continuously and you have signs of CO poisoning such as dizziness, headache, vomiting or flu like symptoms, find fresh air and call 9-1-1 immediately.

Will a carbon monoxide detector beep if the battery is low?

Carbon monoxide alarms alert you with four beeps. A single chirp means the battery is low or the detector should be replaced.

Is 3 beeps carbon monoxide?

A carbon monoxide detector beeping three times means that your device is malfunctioning. It will beep three times rapidly, pause for 15 minutes, and beep again. Some systems may only emit the three beeps once, but many repeat the warning to ensure you hear it.

Will opening a window help with carbon monoxide?

If you experience symptoms that you think could be from CO poisoning: DO GET FRESH AIR IMMEDIATELY. Open doors and windows, turn off combustion appliances and leave the house.

Does the fire department charge to check for carbon monoxide?

In most areas, the fire department does not charge to respond to carbon monoxide alarms or to check for the presence of CO in a residence. However, policies can vary depending on the jurisdiction or specific fire department. It's always a good idea to contact your local fire department for specifics on their policies.

Should I call 9-1-1 if my carbon monoxide alarm goes off?

My carbon monoxide alarm is sounding. What should I do? Call 911 and report what is happening. Immediately leave your residence and wait for the fire department to arrive.

Should there be a green light on a carbon monoxide detector?

If the red or green light on your CO detector is illuminated, that's a sign that the unit has power. If the light is off, replace the batteries and follow the reset steps.

What number should a carbon monoxide detector beep?

The significance of different beeping might mean different things for different types of detectors. If your detector is low on battery, you will likely hear a short chirp every minute. To warn of dangerous CO levels, most detectors will beep 4 or 5 times in a row about every 4 seconds.

What color should the light be on the First Alert carbon monoxide detector?

First Alert CO600 Plug-In Carbon Monoxide Detector

A: That is the power light. It is normally solid red and flashes when there is a problem.

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