First of all, a ver 3 is NOT a ver 4 and the firmware is NOT interchangeable. If you installed ver4 firmware on your ver 3 units, it will not work. Make sure that you are not using the Zeus configuration utility to set them up. The firmware for the ver3 and ver4 SSc's has not been updated to work with the new color combinations and using it will lock up the controller. If you are using the 3 pin waterproof connectors to connect the nodes to the controllers, run a continuity test on the leads of the connectors. A bad batch of these connectors has been released with bad wires and you may have a few.