Nest Thermostat 3rd Gen and Vaillant Ecotec Plus 831

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Stanquest

Hello,

I trust someone would be able to assist - I've looked through the forum and haven't been able to find a thread close to my issue.

I'm trying to install the Nest 3rd generation thermostat with Heat link; I already have a combi boiler, Vaillant Ecotec Plus 831 with thermostat that controls both heating and hot water.

Should I just install the Nest thermostat alone and not the heat link? Since I already have a thermostat that controls the boiler.

Or do I need to install the Nest heat link nevertheless - but the question is how? Please look at the pictures attached to see the PCB of the boiler. It doesn't have the wiring as explained in the Nest manual.

I would very grate if you would clarify and explain best way to go about the installation.

Many thanks
Vaillant Ecotec Plus 831_.jpeg
Vaillant Ecotec Plus 831.jpeg
 
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You mean, when we're averaging 5 or 6 threads a page on installing bloody Nests and Hives, you haven't seen one on how to install a Nest onto a Vaillant, one of the most common boilers on the market?

I suggest that if you can't follow the simple pictures in the manuals, as well as being unable to read hundreds of posts that directly answer your question, then you should reconsider this as a diy project.
 
I’ve asked for a separate “insert-catchy-nature-themed-name controls” sub-forum... got no response!
 
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You mean, when we're averaging 5 or 6 threads a page on installing bloody Nests and Hives, you haven't seen one on how to install a Nest onto a Vaillant, one of the most common boilers on the market?

I suggest that if you can't follow the simple pictures in the manuals, as well as being unable to read hundreds of posts that directly answer your question, then you should reconsider this as a diy project.


Thank you very much Sir! I have indeed searched the forum for exactly my type of issue but no where to be found. I'll be more than grateful if you could point me there.

Oh, I can also indeed follow picture manuals; unfortunately the ("bloody") Nest manuals doesn't feature all boiler models of this world. Again, I would be grateful if you have a manual that does.

Thanks
 
You do need to understand what a room thermostat in it's simplest form actually is, ie it operates as a switch and in order to fire up your boiler it would have to switch together terminals 3 & 4 in your photos.
As you don't have a room thermostat at the moment these two terminals are linked together by the short red wire.

In the case of the Nest the thermostat plus Heatlink must operate together and one can't be used without the other.
I'm not keen on going any further until you've better understood the Nest installation instructions and read the other threads here.
 
You do need to understand what a room thermostat in it's simplest form actually is, ie it operates as a switch and in order to fire up your boiler it would have to switch together terminals 3 & 4 in your photos.
As you don't have a room thermostat at the moment these two terminals are linked together by the short red wire.

In the case of the Nest the thermostat plus Heatlink must operate together and one can't be used without the other.
I'm not keen on going any further until you've better understood the Nest installation instructions and read the other threads here.


Thanks Jackthom. apologies if I didn't make myself clear enough in my original message. I do know what a thermostat does and how it works. Please see attached my vaillant thermostat.

The issue is that the Nest manual doesn't cater for exact connection which the Vaillant ecotec Plus 831 has. As you can see from the Nest manual, 1 & 2 must go into the boiler which my boiler doesn't have. And 6 which is for hot water - again my boiler hasn't got.

I believe the following should be the case but I'm not entirely sure hence my question:

I think I would need to remove the link (red) 3 and 4 on my boiler

Then connect Boiler 3 to Heat Link 2

And Boiler 4 to Heat Link 3

and of course, connect the Live and Neutral from boiler to Heat Link.

T1 and T2 isn't available on my boiler which I think is for controlling the boiler on a low voltage should I not want to use the frequency from Nest (?)



I hope I've been able to ignite your keenness, jackthom?

Please correct me if I'm wrong and I'm grateful for your time in responding. we all learn everyday.

Cheers
 

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You do need to understand what a room thermostat in it's simplest form actually is, ie it operates as a switch and in order to fire up your boiler it would have to switch together terminals 3 & 4 in your photos.
As you don't have a room thermostat at the moment these two terminals are linked together by the short red wire.

In the case of the Nest the thermostat plus Heatlink must operate together and one can't be used without the other.
I'm not keen on going any further until you've better understood the Nest installation instructions and read the other threads here.


Thanks Jackthom. apologies if I
Now if I can help you with anything else, shoelace tying, use of knives and forks, or even breathing, please let me know


How about a cuppa matey! :D:rolleyes::mrgreen:

Your link points to a Vaillant 828... absolutely different to my boiler.
Perhaps an exact search on boiler as well... Thanks!
 
You are correct about the connections required between boiler and Heatlink.

Sorry I failed earlier to spot the two wires, grey & black, in the boiler "bus" terminals.
You already have a Vaillant ebus thermostat connected and will have to remove those two wires to let the Nest have full control of the heating.
 
You are correct about the connections required between boiler and Heatlink.

Sorry I failed earlier to spot the two wires, grey & black, in the boiler "bus" terminals.
You already have a Vaillant ebus thermostat connected and will have to remove those two wires to let the Nest have full control of the heating.


Thanks again, jackthom.

Just to summarise:

1) Remove the grey and black wires from bus terminals

2) Remove red jumper wire from 3 to 4 in boiler

3) Connect L & N from boiler to Heat Link

4) Connect Boiler 3 to Heat Link 2

5) Connect Boiler 4 to Heat Link 3

6) Replace the Valliant thermostat on the wall with the Nest thermostat using the two wires in the wall


Hoping the above will be sufficient to power the boiler, control heating and hot water? As i

What do I do with T1 and T2?

could you possibly explain how hot water will be powered and control with the above connection. Still at a loss here.

Thanks for your reply
 
1 to 5 are OK

6) You can power the Nest directly using the 'usb' lead power adaptor. No need for T1 & T2 to be connected if not required.
If the Grey and Black wires do go all the way from the boiler to the wall thermostat directly you could use them to carry the power using T1 & T2, provided there is enough spare cable at the boiler end to reach the heatlink.

As for hot water, it's a combi and only provides hot water when you open a hot tap. There's just no need for any other timing control from the Nest.
 

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