I have this type , although my Ecotec is a 618 not a 624, installed this spring. Ecotec 618, Unistor, 2 CH zones controlled by VR 61, VRC 470, VR 81 upstairs as thermostat for the second zone, VR 40, grundfos brass pump. Also a USB eBus coupler and data logging on a PC, but that's another...