Refer to instructions for repairs. E LIMITATIONS AND FUNCTIONS • • • • • • • • • • • • • • This combination smoke/carbon monoxide (CO) alarm requires constant 120VAC power to operate properly. THERE ARE TWO BASIC SMOKE ALARM TYPES - IONIZATION AND PHOTOELECTRIC. Ionization smoke alarms (such as this smoke alarm) are your best overall choice for reliability and fast response time, since they quickly sense small "invisible" smoke particles and will also sense larger "visible" smoke particles. Phot