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CO alarm went off then stopped

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Guest Guest TP


i was woken up at 5am by my Smoke/CO alarm beeping 3 times then completely stopping. It is a Kidde model and didn’t say either “fire” or “CO detected”, it was literally just 3 beeps.

I have since tested the alarm using the test button and it works fine. It has made no noise since. Should I be worried?


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Guest Kidde Technical Support

Thank you for posting this question on the Safelincs Forum. It is important to use the alarm in accordance with the user manual supplied with the alarm unit to ensure correct operation as per its design. Optical smoke detectors are particle detectors and it is possible that the sound you heard was a ‘transient event’ caused by particles or insect activity (such as very small flies or spiders). Carbon monoxide gas would cause the alarm unit to emit four beeps – see user manual for details.

The test button is a full function test of the alarm so as you have pressed it and the alarm responds correctly this would mean that the unit is capable of detecting smoke or carbon monoxide gas provided it is used as per the user manual. It is important to maintain the alarm and follow the information on the user manual: ‘General Maintenance To keep your Smoke/CO Alarm in good working order, please follow these simple steps: 1. Verify unit alarm, lights and battery operation by pushing the test/reset button once a week. 2. Clean your alarm monthly using compressed air or a vacuum cleaner hose and vacuuming or blowing air through the openings around the perimeter of the alarm. If cleaning does not restore your alarm to normal operation the alarm should be replaced.’

The 10SCO has a ten year warranty and Kidde do treat warranties very seriously. You can contact Safelincs or Kidde for assistance.


Kidde Technical Support

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  • 2 months later...
  • 5 months later...
Guest Kerrie

my neighbour is burning something that sets my smoke alarm off...there is no smoke but a chemical smell coming from their house.

Can anyone tell me what types of chemicals would set my alarm off?

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If it is a an ionisation type, they are operated by the products of combustion so a clean flame will activate it. I once was using a blowlamp in the kitchen, no smoke, and that activated the ionisation detect in the hall. I was using petroleum based instant adhesive in the kitchen which activated the ionisation detector in the hall and when I closed the door/opened the windows it stopped, so I suppose there could be others.

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  • 5 months later...

My smoke/carbon monoxide detector went off at 1am telling me there was a fire, then carbon monoxide. I’ve had a bunch of windows open in the house all night without a problem. It’s the first time this had happened, should I be concerned?

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  • 3 months later...

Our fire alarm went off for a few seconds at 5AM it then said Carbon Monoxide for a few seconds then stopped going off at all.

I went to check if anything was on and found nothing other than maybe the end of a furnace cycle.

I open d windows in each bedroom after checking all in our household.

any idea why our alarm went off both fire and CO for only a few seconds and then stopped?

What additional steps are recommended?

Thank you

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Please check replace-by date on the CO alarm to make sure it is not just getting faulty. With both fire alarm and CO alarm in the unit going off, it is unlikely to be a CO leak.

However, should the alarm still be in date and the batteries in working condition then you might have to look further into your fuel burning appliances. 


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