The safest method is to isolate mains power before opening the panel then change the battery like for like observing correct polarity.
You will create a tamper,so I need to warn you that the panel may be set up for engineers reset and if so will need the engineering code to clear and reset the system.
open panel
tamper alarm goes off
enter your code
change battery, obsere polarity
write today's date on battery
close lid
reset alarm with the use of your user code or engineering code if it's set up for engineers reset.
Remember mains off first !!,
Good luck be safe :)
e manno, February 2013
