How to Troubleshoot for the BRK Model CO5120BN

Check the AC power supply if the red indicator light on the cover of the detector is not illuminated at all and there is no audible chirp, warning that the unit is receiving neither AC power nor backup battery power. Verify the AC power source and replace the 9-volt battery.

Check the AC power supply if the red indicator light on the cover of the detector is blinking once per minute but there is no audible chirp, warning that the unit is operating on the 9-volt backup battery alone.

Check the 9-volt backup battery if the red indicator light on the cover of the detector is blinking and the alarm is chirping once per minute, warning that the 9-volt battery has discharged. Replace the 9-volt battery.

Replace the CO5120BN carbon monoxide detector if the alarm sounds three successive chirps every minute and the red indicator light flashes three times. This indicates that the detector is defective.

Leave the interior of the residence if the alarm resumes 4 minutes after silencing an initial alarm. This indicates persistent dangerous levels of carbon monoxide.

Evaluate the placement of the detector if false alarms occur frequently. Placement in unventilated kitchens, furnace rooms or garages where combustion particles are present may trigger excessive alarms. Consult the manufacturer's instructions for proper location of the detector.