The ZVR or ZSR Series relay boards are available for 3, 4 or 6 zone options. If your system has more zones, you can add any number of additional zone panels. They can all tie back to a master zone panel to simplify the installation by selecting one main panel as a “master” panel. Any number of additional panels may be set up as “slave” panels and are wired together via the “COMMS” terminals.
Refer to page 36-37 of the Wiring Guide for further information: