First Alert 9120B Smoke Detector Keeps Chirping/Beeping
Posted by Russell Wright on April 4, 2014
I had a smoke detector that kept chirping. Thinking it was a battery problem, I replaced the battery even though the battery that was in it tested out okay. Now, this is a smoke detector located at the top of the stairs, so I had to get my folding ladder out to get to it. You know…two ladder feet on a stair and the other two feet of the ladder on the top of the stair landing with 6′-1", 210 lb. me standing on the ladder, reaching for the ceiling. Not a pretty sight. And, to make matters worse, the dang thing kept on beeping after I replaced the battery.
So, standing on the ladder (I didn’t put it away because I thought this might happen), I removed the smoke detector by rotating it CCW to detach it from its base so I could get to the plug on the back. After unplugging it (and not falling off the ladder) I took it downstairs and removed the cover. There are three plastic tabs/clips that can be released, one-at-a-time, to allow you to remove the cover. I took the naked smoke detector out to the garage and fired up the air compressor (what…you don’t have one?) and blew the sensor clean. I reassembled the detector (snapped it together) and put the original battery back in it and voila, no more chirping!
This detector is located near our attic fan, so I’m thinking it gets a lot of dust and particulate matter blown by it when the fan runs. However, it looked very clean on the inside, but blowing it out appears to have done the trick.