D54.21-1125-04
1 Press the down button (23) 16
Within 60 seconds after the central electronics (5) is in self-test mode
2 Press ON-OFF button (18).
3 Check of multiple display (8).
If OK is displayed in the multiple display (8), this means that the ON-OFF button (18) is OK.
If F is displayed in the multiple display (8), this means that the ON-OFF button (18) has a fault.