The First Alert PRC710 uses a photoelectric sensor ... if the alarm goes off while you're not home. Backup power: Hardwired smoke detectors require a backup battery to power the unit in the ...
Beeping or chirping smoke detectors are beyond annoying. Usually, a chirp every 30 to 60 seconds just indicates a low battery. “If it has a 9-volt battery, it needs to be changed,” says Battalion ...