Hello - maybe I can help. If the installer is *super protective* of the code he installed, that means the installer code , most likely is the SAME for all of his / their account, a bit dangerous as we have unique numbers for the systems we install, since the customer owns the equipment. At least that is the way we operate) There is a "chance" that the following will work, with little front panel effort. please have pen and paper ready, Ok?

First:Unplug the battery, then disconnect AC power.

Restore AC Power
Within 50 seconds press * + # XX the same time. It should come up with "20" showing in the display.

Press #20. The system will read back the installer code, one digit at a time (ignore leading zeros)

Write that number down.

. Don't try to use the installer code as a arm/disarrm code.

I hope this helps, please advise , and thank you for your time.

Sorry , my bad, used to 3000 LX - The 5000 is even more difficult as the same installer code "read back" was limited or deleted in this model.. I do not have enough information to provide you to do a hard reset of the EEPROM -- do you know the panel firmware version , as it depends on that as well. Some options : 1) If you own the panel (as above) you should ask the dealer to "download" the DEAFULT installer code from his office. There should be no or minor charge for this. 2) Call another Honeywell dealer and ask them if they will provide you a new EEPROM. This will default ALL settings, so you will have to re program and enroll modules. I am sorry I could not complete the answer as listed , thank you for your time.