I have a y-plan combined HW/CH open vent conventional system. There are other separate systems for HW e.g.Rayburn and Solar. Consequently the 3-port valve is almost always programmed in the CH position and is permanently energised. Can the valve be plumbed the other way round so the CH port is normally open, thus saving power and strain on the actuator motor. The wiring would have to be altered too of course. I suppose I could do without the valve altogether,but I would prefer to keep the HW option as a back-up for the other sources.