11:35PM | 12/30/13
Same exact problem. Wires in ceiling seemed to be chirping! Drove us crazy. Finally DID find the problem. In the same room where the chirping was coming from -- and behind a couch against a wall -- was a CO detector. Just a battery type CO detector. Pulled the battery on it and no more chirping! I too thought it was the wires in the ceiling box chirping. Of course that's impossible and thankfully it is -- it was the separate, stand-alone CO detector with a bad battery playing ventriloquist! And doing a very good job of it!! Good luck.


12:52AM | 02/11/14
I had the same issue and forgot that I had a separate CO detector that plugs into a wall outlet. The CO detector's 9 volt battery needed to be replaced and produced a loud reminder chirp every ~45 seconds. After replacing the battery, the chirp no longer sounded.


03:29PM | 02/11/14
Try taking them down and blowing them out with a can of compressed air. Many times during construction they get dust in them and over time they build up dust also which triggers the chirpping. It worked for me. I thought that I was going to have to replace mine in a 5 year old house.


07:21PM | 02/16/14
Just finished with this issue.


1. Clean the dust out of them with a can of compressed air and/or a vacuum cleaner. Feel free to remove the detector from the ceiling but do NOT open the detector itself. Get as much dust, dirt, and spider webs out as possible.

2. If #1 fails, and the smoke detector(s) are more than 10 years old on average they may need to be replaced.

3. If you have removed all the smoke detectors and still hear chirping, check for other smoke detectors and CO2 detectors. A general rule of thumb is each level of your house should have 1 smoke detector. C02 detectors should be located outside the furnace room in your basement and outside the bedrooms. If you find any of these disconect the power and/or batteries to take care of the chirping.

Hope this helps! I was driven crazy at 3 A.M. 2 times this weekend before finding the last of them. :)


01:28PM | 03/09/14
I am so relieved to not be alone in disgust over a chirping hard-wired smoke alarm! I have a highly fearful dog who comes unglued at the midnight detector malfunctions -so at 2am one particularly rough night, I ripped the chirpers off their mounts, and took a hammer to them in the garage. They shattered nicely and stopped chirping. I then brought my dog into the garage to inspect my handiwork, and he was most appreciative. We all got some sleep. My vote on causes is temperature change, plus old devices.


11:25PM | 03/15/14
Yes it was the co detector for me also.Now we can sleep.Thanks for all the great advise.


01:51PM | 04/12/14
We suffer with the wired smoke alarm chirping disaster from time to time. Today I would have SWORN it was the smoke alarm again and the sound was moving from unit to unit. My hubby wasn't here to help so I went to Google in desperation. I saw this thread and it made me check the CO2 unit. It was the 100% the culprit. The sound it makes can absolutely trick your ears into believing it's coming from somewhere else.

Thanks for the advise, it worked for me. I wouldn't have thought to check the CO2 unit for a long time, if ever.


08:13AM | 04/23/14
We had the '3 chirps' problem happen: 3 chirps, pause, 3 chirps, then nothing. It was fine for a couple of months, then it happened again. And again. As other folks in this thread indicated, it was the CO2 detector.

I looked up the First Alert manual to see what the chirp code meant. Just once/minute would be low battery; 3 chirps is the alarm indication, but would be continuous; 3 chirps, pause, 3 chirps is the test mode. Of course, no one was testing the CO2 alarm, so it was a puzzle.

I unscrewed the alarm to inspect it. It was clean, the LED was green, etc. Then, as I went to put it back, I noticed some movement: the black wire on the alarm was loose from its wire nut. If it was twisted just right, it would lose connection with the house power. So much for using an electrician!

If this is the problem for you: with power off, unscrew the wire nut, straighten out the alarm's wire, stick the alarm wire into the wire nut first, follow with the copper from the house, then twist to make it snug. Over-tightening can cause it to ride up and slip out. (don't forget to turn the power to the detectors on again)

I haven't had the problem again. As one writer indicated - it may have been related to a temperature change: after a few warm days, it got cool, and the metal may have contracted just enough to lose contact with the house power, and then recontact. The manual doesn't mention it, but it may be that the right pattern of random power connections gets interpreted by the alarm as a test. (like the old rotary phones: you could click the receiver to imitate the clicks for each number)


10:16PM | 04/28/14
Thanks so much!! It turns out to be our CO2 monitor also. Whew! So happy to find this site.
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