Confused C plan gravity system

[stem]

So using the WORCESTER GREENSTAR 30CDI CLASSIC REGULAR BOILER run on s plan , am i right in assuming the hot water will be pumped through tank as both heating and water are pumped helping with fast recovery?

Yes that is correct, with simplified diagrams, this is what you have now.

.... and this is an S Plan

 

[whyme!]

Cool so my understanding is good then. Best go buy a new boiler and another 2 port valve, just hope my 28mm one can be utilised somehow!! best get some 28mm to 22mm reducers too

 

[whyme!]

If converting from C plan to S plan utilising my 28mm 2 port valve, what happens to the white cable that did go to piin 9, the 22mm valves appear not to have a white cable? I assume the other colours work the valve the same?

 

[Terrywookfit]

Make it electrically safe.