Nest 3rd Generation Heat Link

[azzwuff]

Hi All

Apologies if this has been asked elsewhere I have trawled through the nest posts but cannot see anyone with a similar setup. I am currently trying to install the nest 3rd gen heat link box which replaces my old boiler programmer.

Here's what I have tried:

My old programmer had 4 wires going into it ( ) N/L/CH ON/DHW ON which I disconnected and connected to the nest heat link. (Bare with me as this is all new to me) The heat link gave me 3 options for both Heating and Hot Water () and I connected to the call for heat and call for hot water respectively (note my writing in the image is the wrong way round). The nest unit powers up and I can hear my wireless thermostat telling it to power the heating/hot water (click noise) but the boiler does nothing. I saw on another post someone using jumpers from live to common on both () should I be doing this? I am a complete amateur so I'm unsure about what the common or 'Satisfied (Optional)' do.

I have not touched my old thermostat which incidentally looks like this () as the nest one works wirelessly off mains or 12V. Do i have to do anything to my old thermostat or will the new system render it useless, does it look like it has a 12v feed which I could use and replace it with the nest thermostat instead of using a plug?

Thanks again for any advice, i hope this all makes sense with my very basic knowledge. I have an electrician friend coming the weekend after next but hoped I could save him the trip and me some funds...

 

[hertsboilers]

link live to the two commons in the heatlink.

Use a pair of existing cable between current programmer and thermostat, T1 and T1 to the new Nest stat.

 

[azzwuff]

Thanks, Thanks, Thanks this worked a charm, appreciate it. I now have two thermostats one ugly dial one on my wall as seen in the pics above and a wireless nest one plugged in. What is my best course of action for removing the old one? Clamp the wires and cover it with a socket plate or is there a way I can check if any of the cables to it are 12v and i can screw my nest thermostat over the hole and use it for its 12v power draw?

 

[azzwuff]

Electrician took the old thermostat out the boiler circuit and ran 12v power to the old 'hole' in the wall. Thanks Again

 

[Jamie7755]

Hi all sorry I know there's many nest posts but I've looked through many and can't see any that can help I've tried many different ways of wiring up the heat link just something still isn't working

Thanks

See below pictures of my current wiring for a drayton programmer which wires go where on the heat link ?

 

[Steelmasons]

An additional link between HW off/HW on should sort out any issues.
I'm not quite sure why terminals 3 & 5 used 2 link wires when it clearly requires 3.

 

[Jamie7755]

An additional link??

Black and blue together on N do they need to stay together

I wired the link up as a y plan and linked live to 2 and 4 stills nothing boiler doesn't fire up iv tired other ways that I found online but still nothing

Not sure what I'm doing wrong

 

[Jamie7755]

I just thought about the airing cupboard and what wiring is in there I just checked and saw the box on the wall is this a junction box??

 

[Steelmasons]

I wired the link up as a y plan and linked live to 2 and 4 stills nothing boiler doesn't fire up iv tired other ways that I found online but still nothing

3 & 4 have also been bridged....
Crack on with it as you're doing a sterling job..
While you're @ it link terminals L/1/2/3/4 , remove neutral from terminal and park it safely.

 

[Jamie7755]

Photo

 

[Steelmasons]

I just thought about the airing cupboard and what wiring is in there I just checked and saw the box on the wall is this a junction box??

I guess so.....remove front cover of box and identify all earths and neutrals , all other cores should be linked together.
Hope this helps..

 

[Jamie7755]

Then can I connect up the heat link to the junction box?

 

[Steelmasons]

Go for it..

 

[Jamie7755]

Helpful..

 

[stem]

Not sure what's happening with this thread........

Jamie 7755 first of all, you should have started your own thread. Posting your question on someone else's is known as Hijacking and is against forum rules.

Also, posting a photo of a backplane with a set of wires doesn't really help. The vast majority of programmers use the same backplane but the terminals carry out different functions for different products. We need to know where the wires go.

So, first of all, you need to identify from your existing programmer (details will be printed inside it, on the back, or by consulting the instructions) what each of the terminals is for. OK N & L are standard but you need to find out what functions terminals 1, 3 and 4 are for. It will probably be as below, but please check before assuming it's correct.

1. Hot water off (or satisfied)
3. Hot water on (or call)
4. Central heating on (or call)

Then once you know what they do, look at the Heatlink instructions and find the corresponding terminals that carry out the same function in this instance.

Heatlink 3. Central heating on (Call)
Heatlink 4. Hot water off (Satisfied)
Heatlink 6. Hot water on (Call)

Then you need to link the L terminal to the two common terminals numbers 2 and 5

After that you need to remove any existing wired room thermostat as the Nest also does this function. Once it is disconnected, the two terminals where the two live switching wires came from need to be linked together, otherwise you will have an open circuit and the heating won't work.

Finally you need to get 12v to the thermostat. This can be by using a mains powered adaptor, or by wiring it to T1 and T2 to the corresponding terminals at the Heatlink.