Nest Thermostat (3rd Gen) - Dual Zone

[Lecclu]

I have same system on a new build, which I am trying to install install Tado on one floor only. The downstairs are all manual valves so hope to keep them on the original ESI thermostat. However upstairs I wish to change to Tado using the wireless receiver.

Is there any problem powering the receiver from the 230V and using COM->RH, NC->+V, NO->OV at the low voltage section of the board?



*****
Moderators note

Other information can be found in https://www.diynot.com/diy/threads/...ith-nest-thermostat-3rd-gen-dual-zone.604774/

But please keep each user's problems separate
*******

 

[RandomGrinch]

Is there any problem powering the receiver from the 230V and using COM->RH, NC->+V, NO->OV at the low voltage section of the board?

As in your second diagram....

there shouldn't be a problem.
However, it would be best to run two separate cables - one carrying the mains supply and the other, the (extra) low voltage one; don't get them mixed up, or as in your first diagram - boom!

Just a word of caution - so far, you have been the only person to keep one of the ESI thermostats.
Again, theoretically, having a mixed system shouldn't be a problem, but as no-one has yet tried it, keep an eye out for any strange behaviour from the original stat.

 

[Lecclu]

Thanks, I appreciate your help. Been trying to work out this system for a couple of days before coming across your post!

 

[RandomGrinch]

Thanks, I appreciate your help. Been trying to work out this system for a couple of days before coming across your post!

Glad to help
Please let us know how you get on.
Good luck!

 

[Lecclu]

All seems to be working from the initial test!
I'll watch it closely but both seem to be able to work independently. Downstairs works on the original thermostat controlling all radiators. Upstairs is working on the tado wireless reciever and smart valves.

Tado said they are not compatible with the ESI system but they wouldn't explain what the conflict was.

Glad to help
Please let us know how you get on.

 

[RandomGrinch]

All seems to be working from the initial test!
I'll watch it closely but both seem to be able to work independently.

Brilliant - well done!

Tado said they are not compatible with the ESI system but they wouldn't explain what the conflict was.

It's definitely not Tado's fault.
I doubt any thermostat manufacturer would say that their systems were compatible with the proprietary connections on the ESI - even though, now we know that the solution is so simple!
Even the zone valves could be converted with an appropriate change of connector!