There are a few reasons your siren might beep. 1, your main panel may have a problem such as a low battery, and your siren is set to repeat warning beeps about those problems. 2, your siren may have an internal problem, such as a low battery, loss of AC power, or a tamper. 3, the siren dip switches next to the battery may be set incorrectly. Both should be down, towards the battery.