If the user &/or engineer codes are lost,
1. First remove mains power before opening the case & then disconnecting the battery.
2. Identify & remove the NVM chip (IC4) on the main pcb
3. Reconnect the battery, then re-apply mains power.
4. Refit the NVM chip (note the locator marker position)
The end station loads the factory default access codes (User 1: 1234, engineer: 7890).
5. THEN carry on to RE-PROGRAM the WHOLE SYSTEM.
Without the Installation manual, you're st***ed.
Suggest you find an engineer who knows this panel
acorn, February 2010