Do you by any chance have the "separate schematic for internals" (of the valve)? I find it a little difficult to understand:
As far as I can see, the situation with 230V on grey (only) only arises when neither CH or HW are calling for heat - in which case I don't see why (let alone how) one would want any voltage (5-150V or otherwise) on the orange wire (which feeds the pump and bolier). I guess that,as so often, I'm missing something!
Many thanks (and, no, I don't think one can post pictures,or even use symbols, in PMs) - that's very helpful. It looks as if the material in your link will answer my question when I've studied it properly - and that the switchery is a little more complicated than I had been expecting!
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