Initialize Download ID - Reset Defaults - Reset Factory Defaults - Default Panel - Hard Reset

1) enter Installer Code into a PROGRAMMING KEYPAD ONLY (Default 4112) + 800

NOTE:  This is a command to the panel that will reset your panel to default settings, please only continue if you understand that this will reset the panel

2) enter *96 or *97

*96 - Initializes download ID and subscriber account number

*97 - Sets all data fields to original factory default values. 

4) enter *99 to exit programming if you haven't been kicked out of programming

Note:
The Vista 15P does not have partitions, any fields dealing with partitions will not be available on the Vista 15P

Programming Manual For More Information:

https://turbifycdn.com/ty/cdn/yhst-51756635596032/honeywell-vista-20p-control-panel-programming-guide.pdf

GeoArm can assist in changing the installer code upon activation.

vista-20p-honeywell-8-zone-alarm-control-panel-93