Lilly

Hi just moved into a property which has this alarm previous owner never used it so has no idea I was cleaning and the box it felt warm on one side I was rather concerned about that so I unscrewed the unit wow! The alarm went off and wouldn’t stop no matter what I tried I tried the master code still didn’t stop I’ve had to isolate the alarm from main power I’ve got the user manual but it seems I need the code and no one knows what it is any help out there please?my goodness it was so loud