How to connect two new Nest 3rd gen heatlinks? (photos)

[stem]

OT regulates the heating water temperature according to demand / anticipated demand. But unless things have moved on since I last looked into it, it doesn't work very well with more than one heating zone. This is because the two zones may require different water temperatures but that's not possible when there's only one boiler providing it for both of them.

I have asked a few individuals that have installed OT and as yet no one has reported back any significant energy savings, one or two said there might be.

 

[Pipps]

@stem - Firstly, thanks for confirming that OpenTherm is not worth the effort.

More importantly, I am now delighted to report that the dual zone central heating system is now working perfectly.

I could not have done it without your patient, detailed and expert assistance. Thank you.

My only remaining question is... how much is your fee?