If the unit is hardwired or just battery-operated, press the Test button. You don't need to hold it down. Press and release, and it should go back to normal "stand by" mode.
How to Reset an Alarm
April 28, 2021
If the unit is hardwired or just battery-operated, press the Test button. You don't need to hold it down. Press and release, and it should go back to normal "stand by" mode.