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First Alert Model 9120 (NOT 9120B) Battery Replacement??

New Member
Joined: 6 months ago
Posts: 1
Topic starter  

My First Alert Model 9120 (AC-powered) has begun chirping at me, which made me think there's a battery that needs to be replaced in there somewhere. I unscrewed it from the ceiling to get a bit of a better look (it's attached to the ceiling because it is hard-wired), but I could not find any drawer, screw, or compartment that looked like a place for a battery. I looked up the manual for it and I could only find that the 9120B will chirp - not the 9120 - and that the 9120B has a drawer for replacing the battery.


My alarm is 100% a 9120, I cannot find a drawer for battery replacement, and is chirping at me once per minute. I am about to lose my mind over this stupid thing. Can someone help?

Member Admin
Joined: 2 years ago
Posts: 2

Hey there SimpleSnail,


You are correct - according to the installation manual/cutsheet for both units (, only the 9120B has a Side Load Battery Drawer for easy battery replacement; the 9120 does not.


If the unit is continuously chipping, it means that it is at its end-of-life, most likely. So in order to stop the chipping, your best bet would be to replace the entire unit. FirstAlert doesn't manufacturer the 9120 any longer, so you would be upgrading to the 9120B, which will allow you to change the battery out in the future.


Let me know if this helps. Thanks!