I have recently been given an accenta g3 alarm panel and keypad which was brand new in the box to replace an existing alarm. I have installed the panel and keypad but every time i switch the power on the alarm sounds. i have tried entering the factory set user code but no joy. The power light on the panel and the keypad light up but it isnt lighting up any fault on the zones or tamper. the only thing i could think of is there is no battery supplied do i need a battery for the alarm to stop? any advise would be much appreciated thanks.