As said yours seems to be connected DHW only
View attachment 426382 so not sure if you should use terminal 3 or 4, I will have a guess running some sort of C Plan? What motorised valves do you have if any, the C Plan normally no motorised valves, and it runs just boiler for DHW and boiler and pump for CH, the Hive has a software fix, so it is one of the few that can work C Plan, Wiser does not have the software fix.