Worcester junior 24i and Nest thermostat

[Brian Spannenburg]

hi all,

I have a Worcester junior 24i combination boiler. At this moment there is no room thermostat installed. To make my life a bit more convenient i would like to install a Nest thermostat.

Is there anyone at this forum that has some experience with this?

• Is the boiler compatible with the Nest thermostat?
• And if so, how should the heat link be connected tot the boiler?

Any help is appreciated (not many people in the Netherlands have experience with Worcester boilers).

Regards Brian

 

[Brian Spannenburg]

I've just finished installing and i'am happy to say it works just fine

 

[Jonhill65]

Hi, I'm just about to do the same tomorrow with the nest with my Worcester. Which terminals did you use to complete the installation.
Thanks in advance

 

[Brian Spannenburg]

L and N on the heatlink should have constant power. I’ve connected it to a power outlet.

Ls to common port number 2 on the heatlink.
Lr to call for heat port number 3 on the heatlink.

And don't forget to remover the bridge that connects Ls to Lr.

 

[Jonhill65]

Hi, thanks for your help on that. Just done it and it works a treat.

 

[lpoolck]

Hello, digging up an old thread but is the bridge that needs removing within the boiler?

Also did you put a loop from LS to L on the heatlink?

Thanks

 

[stem]

Ls (live supply) and Lr (live return) refer to the boiler terminals. When there isn't a thermostat installed, a link is inserted between the two terminals to complete the circuit. If there is already a thermostat fitted, the link will have been removed when the thermostat was installed.

As has been said:
Ls to common port number 2 on the Heat link.
Lr to call for heat port number 3 on the Heat link.
Plus a 230V supply to N & L. No links elsewhere required.

Brian gives poor advice though when he says:

L and N....... I’ve connected it to a power outlet.

The constant power should come from the same 3A fused supply as the boiler and not a separate power outlet, as per the diagrams in the Nest manual.

 

[lpoolck]

Thanks for your reply stem.

Yes, I already have a thermostat (dryton digistat scr). It's also a 3rd generation nest.

It has 5 core flex to the current thermostat. The current set up has the following terminals: N, L, Common, Call and earth (even though the stat plastic).

So would it just be a case of putting N and L in the respective terminals on the heatlink and common in terminal 2 on the heatlink and call in terminal 3 on the heatlink?

Or would I also need I also need a loop from terminal 2 to L on the heatlink?

Thanks

 

[stem]

Or would I also need I also need a loop from terminal 2 to L on the heatlink?

No links elsewhere required.

All you need to do is.

N = N
L = L
E = E
Ls = 2
Lr = 3

And that's it, unless you are using T1 & T2 to power the Nest thermostat.

 

[lpoolck]

Thanks again for your help stem, I thought that was the case but when I did some research a lot of people had went with the install where they put in a loop from terminal 2 to the L.

So they did the following:
N = N
L = L
E = E
LR = 3
Loop = From L to 2

 

[stem]

There are lots of different boilers, systems and methods of installation so what's right for someone else's system, may not be right for yours. In your case Ls goes to 2, so no need for a link. If your installation also needed a link between L and 2 I would have said so.

 

[lpoolck]

All wired up and working, thanks again Stem.

 

[Retro_uk]

Hi there. Hope it's ok to bump this thread up? I have the same Worcester 24i Junior combi. This model here:

and wondered if I could ask a couple of questions. I am assuming if I am starting from scratch then I'll need to get some cable to make the connections to the heatlink, or is cable provided in the box?

Also, I don't suppose the OP of this thread took any snapshots showing the wiring? I'm confident enough to try this, as I used to do automobile electrician many moons ago, so am ok tearing things apart etc

I currently have no thermostat connected to my combi, so I'm assuming I can just get the stand for the Nest thermostat and plug it into the mains with a supplied plug/usb cable? Thanks

 

[stem]

I am assuming if I am starting from scratch then I'll need to get some cable to make the connections to the heatlink, or is cable provided in the box?

You will have to provide your own cable, virtually every installation is different. Some have combi boilers with simple connections, Y and S plan are more involved. Some reuse existing cables, some require a meter or two, others many metres. So it would be impossible to provide cables for all circumstances. For wiring to a boiler, I usually use a minimum of 0.75 mm2 heat resistant cable. Make sure the boiler's fused connection unit has a 3A fuse in.

I currently have no thermostat connected to my combi, so I'm assuming I can just get the stand for the Nest thermostat and plug it into the mains with a supplied plug/usb cable? Thanks

Yes.

You will also have to leave the existing boilers internal timer set to be permanently 'on' 24/7

 

[Retro_uk]

Ok, I have managed to get out and grab some cabling and just want some last minute verification please.

The wiring for the heatlink should be as follows:

Heatlink L > L on boiler
N > N on boiler
2 > L (I can link small cable from L on the heatlink save running to the boiler?)
3 > Lr on boiler and remove the small link between LS and LR on the boiler?

Cheers