The first thing to do is to give the “AWAY” Button a quick push, not a long push.
This will stop the beeping, BUT WILL NOT FIX THE FAULT.
If you have a monitored alarm then it could be a failure to communicate, try holding down the “9” button for three seconds to send a test signal through to the monitoring station.Other than that your alarm needs a service.
If the green “MAINS” light is flashing, or the power cord symbol on the left hand side of the screen is flashing on and off, it means that the AC mains power to the alarm has failed. You could be having a power cut or a fuse on the house electrical fuse box is blown. Check your fuses, if they are all good — it’s time to call us.