sorry should have been clearer, i'll like to see the System Summary page of the controller on a HCE80. Because if that can show the individual zones' heat demand, then we can try and work out how. But if that can't or is showing all the heat demand for the controller against 1 zone, then we have to conclude that the HCE80 does not request Heat Demands from the controller individually but instead sums them up and sends them as a single heat demand for the entire controller.