This is a photoelectric smoke alarm, meaning it may provide better detection of larger, visible fire particles (the kinds associated with slow smoldering fires). Fire safety experts advise using both photoelectric smoke detectors, like this one, and ionization smoke detectors which may be better at detecting small, less-visible fire particles (those that emit from fast-flaming fires). Install both throughout your home for optimal smoke & fire detection.
Fire: The red LED will flash and be accompanied by three long alarm beeps. The alarm will repeat this pattern until unit is reset or smoke is eliminated. Carbon Monoxide: The LED will flash, and four short alarm beeps will sound. This continues until the smoke & carbon monoxide alarm is reset or the CO is eliminated. Low Battery: One chirp and the LED will flash red. This pattern will continue every minute for the first hour. After the first hour the red LED will flash once every minute accompanied by the chirp sound. Alarm Memory: Alerts a user if smoke or CO has been detected in the last 24 hours. If smoke has been detected, the red LED blinks every 15 sec. If CO has been detected, the red LED blinks twice every 15 sec.
This smoke & CO alarm is UL Certified, with a 10-year limited warranty. Meets the requirements of UL 2034, UL217, NFPA72, (chapter 11 2002 edition) The State of California Fire Marshal, NFPA101 (One- and two-family dwellings) Federal Housing Authority (FHA), Housing and Urban Development (HUD).