CD3500 & CD4000 Installation and User manual
Backup power supply
When the batteries are running low, Codoor will operate with the
buzzer sounding a low tone. The lock has a backup power supply
sufficient for a limited number of openings once the batteries have
In order not to jeopardise security, the backup power supply
is restricted to 50 openings, after which the backup function is
terminated to conserve the remaining battery power. However, to
allow battery replacement to be carried out by the person in charge,
the programming code is not disabled, to allow the door to be
Changing the batteries
When the unit's batteries run out, Codoor will stop working. The lock
has a backup power supply that will allow the door to be opened a
limited number of times, but the batteries should be replaced as soon
as they fail. Follow these steps:
Remove Codoor from the door.
Remove the batteries from the rectangular shaped holes on the
lower part of the back of the unit.
Always change both batteries. Changing only one battery will
dramatically reduce the life of the new battery. The batteries
should be lithium type (2 batteries type U9VL). See Technical
Re-fix the housing.