I have copied this from a recent post of mine here:
(Follow Optima Compact instructions (terms 13 & 23 for the Accenta 6).
If your system is NOT Accenta 6, do not follow these instructions!
You must only undertake this work if
A. You are electrically competent.
B. Your system is NOT under contract.
C. You do this at your own risk.
You may have to clear the NVM.
This will wipe any programmed information off the chip and reset to factory conditons.
Or, if you have the engineer code, you can do the same via the RKP.
From Day mode, press PROG.
Enter engineer code (factory set at 9999 - if this does not work, then the installer has set his own code).
Press SET twice.
Factory conditions are re-installed onto the chip.
To reset to factory conditions the harder way:
With either system: Power down mains. Remove front cover. Disconnect battery.
With older Optima: Remove all wires from terminals 9 & 19. Fit wire link between the two, and apply power.
With Optima Compact: Remove all wires from terminals 13 & 23. Fit wire link between the two, and apply power.
System will now power up with no alarm condition.
Remove the wire link, replace the original wiring, checking the ATTACK led goes out. The Zone Leds will now show when each zone is breached.
Refit the cover, checking the TAMPER led goes out. When the system is clear, it will go into DAY mode & then the NVM will clear and factory conditions apply.