Have just deleted an epic explanation of my problem because by the time I reread it it made no sense to me. Instead will prepare for the barrage of "its simply you fool" by asking this question.
How do you wire two separate properties with their own separate power supplies running there own separate controllers two a single boiler?
Even with relays wont you be sharing the circuit (at the boiler) between each property? Have spent the day bent double in a tiny hole under the stairs and I think its stopped the blood to my brain.
What I was thinking about was the pump over run return , I was asking what wiring goes to the boiler . It may have a permanent live , switched live for the boiler, neutral and a pump return for over run , if not then above is goodi
Sintra, I'm pretty sure your penultimate diagram was where I got to before chucking in the towel and coming to the conclusion that all the control needs to be in the same circuit or as you suggest the boiler goes on its own circuit which will be a lot easier to achieve at the end of the day. Unless anyone else has any bright ideas i will inform the customer this is what needs doing.
Sintra, Ray many thanks. This is such a useful site for a sole operator, when sometimes you just cant see the wood for the trees and need a little confirmation from others
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