The end-of-life signal on a First Alert carbon monoxide (CO) detector typically sounds as a series of chirps or short beeps (often 5 times per minute). On many models, this is accompanied by a flashing light and/or the word "END" or "ERR" appearing on the digital display.
CO alarm life span and end-of-life signal
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.
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.
1 Chirp (about 1x per minute): Low-battery chirp
Causes: Low battery. Batteries facing wrong direction.
For alarms manufactured from February 1, 2006, onward, the CO alarm will display an End message when it has reached the end of its life. Similar to older models, the alarm will emit a quick beep every 30 seconds to indicate that it needs to be replaced.
Our CO Alarms are not typically formulated to register CO levels below 30 ppm.
Carbon monoxide alarms alert you with four beeps. A single chirp means the battery is low or the detector should be replaced.
It is also a good idea to know the signs of a potential CO problem:
Placing the detector too close to combustion sources may trigger frequent alarms caused by localized temporary buildup of CO. Fossil fuel-burning appliances may not be burning fuel completely. Check pilot lights/flames for blue color.
A low battery is one of the most common and easily fixable causes of a beeping carbon monoxide detector—but it's not always as simple as it sounds. Even a freshly installed battery can fail if it's not seated properly, the wrong type is used, or the contacts are corroded.
1 beep every minute: This means that the detector has low batteries and you should replace them. 5 beeps every minute: This means your alarm has reached the end of its life and needs to be replaced with a new carbon monoxide alarm.
Answer. A carbon monoxide detector itself is usually white or gray, but it typically has indicator lights. A green light usually means the detector is working properly, while a red light often signals an alarm or a problem. So, a carbon monoxide detector should show a green light when it is functioning normally.
How long does it take to get carbon monoxide poisoning? In high concentrations of carbon monoxide, it can take fewer than five minutes to get carbon monoxide poisoning. Under lower concentrations, it can take an hour to two hours to cause poisoning.
The Lifespan of Carbon Monoxide Detectors
The typical lifespan of a carbon monoxide detector is eight to ten years.
Because carbon monoxide is slightly lighter than air and also because it may be found with warm, rising air, detectors should be placed on a wall about 5 feet above the floor. The detector may be placed on the ceiling. Do not place the detector right next to or over a fireplace or flame-producing appliance.
Aim for about 800–1,000 ppm while rooms are occupied. Short peaks above 1,000 ppm are normal, but if levels stay around 1,500–2,000 ppm, bring in more outdoor air. Workplace limits (5,000 ppm over 8 hours) are legal ceilings, not comfort or cognition targets for home or office.
A single chirp every 30 to 60 seconds usually indicates a maintenance issue, such as a dying battery or an expired unit.
The very common source of CO poisoning is unvented space heaters in the home. An unvented space heater uses combustible fuel and indoor air for the heating process. It vents the gases it makes into the room, instead of outdoors.
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.
Sooty or yellow/brown stains on or around boilers, stoves, or fires. Smoke building up in rooms. Yellow flames coming out from gas appliances except at natural gas fireplaces. The pilot lights blow out frequently.
The OSHA personal exposure limit (PEL) for CO is 50 parts per million (ppm). OSHA standards prohibit worker exposure to more than 50 parts of CO gas per million parts of air averaged during an 8-hour time period. The 8-hour PEL for CO in maritime operations is also 50 ppm.
Symptoms of Carbon Monoxide Poisoning
Low levels of CO poisoning can be confused with flu symptoms, food poisoning or other illnesses and can have a long-term health risk if left uncorrected.