Yeah 100% efficient but I still cant see how it will be cheaper to run
Even the sales gumpf says ideal for replacing LPG or oil. The control Side of things....The boiler has a built in pump and the control connections R and P are Volt free so do not follow a conventional S-Plan diagram other wise your supply 240V to the boiler PCB and damage it. You will have to feed grey of both valves from R in boiler and connect oranges of both valves to P in boiler. This way the volt free switching is switched from the micro switch in the valves... When the micro switched is closed by the room or cylinder thermostat calling for heat, 240V will be supplied to brown of either valve depending on what's been called for, the valve will motor round and close the switch between grey and orange.