As you are trying to arm the alarm, the system has a feature that informs you that a magnetic sensor is opened in zone 1, 2 or 3. In order to stop the flashing, you will simply have to press the arm button again.
This occurs when the door/window magnetic has been left open for more than 5 minutes and you are trying to arm the alarm.
Answered by: Honeywell Home Consumer Support
Date published: 2019-01-25