Out of the box as new the factory codes are as follows :
Limited user (5678)
Master user (1234)
Engineer (9999)
So to change the ltd user code one presses the double arrow up or chevron button then 4 then enter master user code followed by your new limited user code twice.
IIRC the panel double beeps after the second entry of the new ltd code if it has stored it successfully.
If the installer has changed the master or engineer from factory defaults and can't remember these codes, then the panel will have to be returned back to factory settings and reprogrammed
e manno, April 2013