This is kind of an odd one. Recently, my alarms have been going off. It started a couple weeks ago where my neighbor said the carbon monoxide alarm was going off for 10-15 minutes then stopped. Last Saturday, it seemed like only one of the carbon monoxide alarms was going off, so I changed the battery and everything was fine. Last night, everything started going off, carbon monoxide and fire alarms. I unplugged all the carbon monoxide alarms in the house ( excluding the one in the basement above the boiler ).

I checked the manufacture date, January 2015. They were probably installed by the fire department when I bought the house last year.

How can I debug this? I was planning on trying to clean them and change all the batteries. I can't imagine they need to be replaced they're still too new.

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    You seem to be assuming that the devices are malfunctioning. Why?
    – isherwood
    Sep 2, 2016 at 16:36
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    CO alarms don't age like smoke alarms. You don't have any other way of testing whether there's CO present so you have to assume it is. At the very least you need to shut off the gas supply (to stop all gas-burning appliances) including to the floor below if it's a flat. And ventilate. And that's mainly so it's safe for someone to come in and check properly.
    – Chris H
    Sep 2, 2016 at 16:36
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    Are these standalone battery only units? Or line voltage interconnected with battery backup? What make/model are the detectors?
    – Tyson
    Sep 2, 2016 at 16:37
  • @isherwood, I'm a programmer, I assume everything has bugs. Also, this just started happening. There hasn't been a rhyme or reason to it. Many of my windows are cracked all the time. And last night, when I got home I left the door open. Plenty of air flow but the alarms went off.
    – user44111
    Sep 2, 2016 at 17:18
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    @Tyson Yes, they're interconnected. Update to this, so I checked the manual and the LED flashing and beeps match up with the CO alarm receiving a signal from the fire alarm that there's smoke. Trust me there's no smoke, and the fire alarms are not going off. Every time I plug the CO alarms in they sound with this the above mentioned status. I can't imagine a fire alarm sending a signal without it going off itself. My plan now is to buy a new CO alarm and plug it in. If it goes off like the others than it has to be the fire alarm(s) sending bad signals.
    – user44111
    Sep 3, 2016 at 15:27

2 Answers 2


You can procure carbon monoxide test gas with a known PPM (parts per million) concentration. Place your CO detector in a small plastic bag that can be sealed tight but squeeze the bag down to reduce the amount of air that is in the bag with your detector before sealing it. Spray the carbon monoxide test gas into the bag that houses the alarm and seal the bag. Wait... Without testing with a known quantity of gas you may always wonder. A short Youtube video demonstrating this can be viewed at www.coexperts.com

  • 1
    The test gas canister is around $20 + HAZMAT shipping. for that amount one can replace their CO alarm :-) Dec 12, 2017 at 23:20

You can debug this by getting another CO alarm preferably a different manufacturer and putting it adjacent to your existing one. If both alarms go off, then you can be certain that CO is detected.

If only your existing (old) alarm sounds and new one remains quiet, call the manufacturer of the old alarm.

Do not unplug your CO alarms as there could be a real danger that you are trying to mute!

Even while debugging heed to the warning all the time. When the warning alarm sounds, move to fresh air.


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