NEST 3, ESI and no "Saitisfied" for HW

Hello,

I'm going to replace my ESI controls and thermostats with 2 NESTS. I have 2-zone + HW GCH. I think I've worked everything out and I'm confident that I can get this done myself.
On the pictures attached you can see main board and zoom on the wires that I can reuse.

They are upside down and partially covered but here is what they are:



N, L, HW ON, CH1 ON, CH2 ON

Hot water stat is connected to the main board with 2nd to the left connector - greenish plug, next to blue.



Simple! Get the power to both HeatLinks, get HW ON and CH1 to 1st HeatLink, get CH2 to 2nd HeatLink and job done. Of course get 12v to room stats from HeatLinks as currently that's 230v
But.. I can't see option for "Satisfied"...

1. Do I need it?
2. Where can I get it from? Any option to hardware satisfied to that stat?
3. Could I rewire anything to get that "Satisfied" feed from the board ?

Many thanks for your help.

Kind Regards
Chris

You don't mention the motorised valves in your system but there are likely three 2-port valves and with that sort of setup you don't need a HW satisfied connection.
It's only using 3 port valves where it's required, in order to get heating running without the hot water cylinder also heing heated.

Hi Jackthom,

Yes, that's correct - they are 2-port valves and there are 3 of them.

I was under false impression that "satisfied" means that water is hot enough... Ah, silly me.
On the other hand - how NEST knows that water is hot enough? Or does Nest doesn't care and just calls for heat for x-hours regardless leaving "hard work" to the stat?

So yeah, I will get on with this tonight and see how it goes...

Thanks once again

Cheers
Chris

Yes the cylinder stat must get its 230V from the 'call for heat' on terminal 6 of the Nest heatlink. The cylinder thermostat then switches this through to the zone valve when heat is required.

Much the same applies for the two heating zones using the Heatlink terminal 3 in each case.

Thanks Jackthom. That's clear. I was wondering if there is a way to have Nest work out most optimal water heating schedule with some cleaver algorithms rather than just "time it"...

With room stats Nest can tell how long it takes to heat up zone so it knows for how long to keep "call for heat" going - apparently in the most optimal way. I wanted some cleaver logic applied to the HW as well...

Cheers
Chris

TBH I don't know if they have any plans to produce a smart Nest cylinder thermostat to connect wirelessly with Heatlink. With Google/Nest You never know.

Hi all, I'm trying to get my heatlink setup and seem to have the same board.

I'm guessing I should pull the 230 v from the L at the programmer connection

Am I right in thinking the following
Port 1 on the heatlink to CH1
Port 2 on heatlink to live
Port 3 on heatlink to N/O (for stat 1)

you would be better starting a new thread, it is against site rules to piggy back, and that way you will get the proper advice