Hi, If the bell box rings when you turn off the power then the back up battery is flat causing the bell to self actuate. Fitting a new battery will give you some time the higher the ah (amphour) the longer you get. Be careful about doing DIY electrics under government legislation ( part P) which came into force in January 2005 strict legislation is now in force in certain areas of all domestic dwellings. If in doubt contact your local building control dept or seek help from an approved part P electrician.
Rob, December 2007
