I installed three new smoke detectors, First Alert 10-year sealed battery models, in late 2017 and early 2018.
Two weeks ago one started chirping as if the battery was going low.
I'd reset it and it would start again. First Alert has some tips on how to clear this, as apparently the most common cause is contamination (such as an insect) in the sensing chamber.
I ran through all of their protocols, and nothing worked.
I went away for a long Labor Day weekend and when I got back the damned thing is deader than a door nail. As in, it won't even respond to testing.
So, I got a bum unit, apparently, that had `1/5th the advertised life.
I've not had a chance yet to get in touch with First Alert about this, but needless to say, I'm not happy.
The other two are live (tested both) and hopefully they will stay that way.
But this just reinforces the old advice to test the units regularly. Had I gone away for a couple of weeks it might have died and I'd have been none the wiser as I'll admit that I don't test nearly as frequently as I should.