Why do smoke alarms chirp intermittently?
The "chirp" will only be caused by issues surrounding the battery or miss-wiring. However, a homeowner may confuse the chirp with an intermittent alarm. Try and get the homeowner to be specific as to what they are hearing. A “chirp” will have a higher pitched tone and sound in equal intervals about once every minute. An intermittent alarm will be random, sound usually for several seconds and have a lower pitched tone. Any of these situations can cause unwanted chirps:
- Battery Pull-tab is Still in the Alarm
The battery pull-tab must be removed after AC power is provided to the alarm.
- The Battery Drawer is Open
The battery drawer must be completely closed for the battery to make contact with the terminals.
- Low Battery
As the battery in a smoke alarm becomes weak, the smoke alarm will "chirp" about once a minute to alert you that the battery needs to be replaced. Note: Only the alarm with a low battery will chirp. No signal is sent through the interconnect wire. The other alarms will be silent.
- Tip for Builder Service Managers
During extended periods prior to occupancy where power is off, Builder Service Managers who maintain new homes prior to sale should be sure to open the battery drawer on alarms to keep the battery from draining. If power is restored temporarily (e.g. to show the home) the alarm will chirp if the drawer is open. The alarm now senses there is no battery.
- Battery is Present but Part of the Terminal is Obstructed
The battery may not be fully making contact with the terminals in the alarm. Check to be sure the battery pull-tab or some other obstruction is completely removed.
- A Different Device or Appliance
Security systems, monitors, carbon monoxide alarms, and other devices have similar low battery or alert signals.