I have a flashing green light which I found out means battery needs changing
But I have tried & failed cos every time I take the cover off the main unit in my cupboard does it make the alarm go off.
Tried turning mains off to it that also makes it go off
So at a loss of how to change the battery

Denise Allen, April 2016

I wonder why it makes a noise when you take the cover off. Do you think it has anything to do with the need to stop people getting inside to disable the system?

You COULD try this:

http://bit.ly/1pbyKyO

It may be helpful to add the exact model of your alarm as well.

Anon, April 2016