Nest Heat Link wiring diagram

[pcdj]

So I've taken the punt in buying a Nest and have consulted the wiring diagram for my existing Digistat and what the Heat Link requires.

I've got these available in the wall...


These connected at the Digistat...


And here's what I presume is the relevant diagram from the Nest manual...


I intend to do as follows...

Black Digistat to Nest 3
Blue spare in wall to Nest N
Brown Digistat to Nest L
Jumper Nest L with Nest 2

Not sure about the remaining red, second, wire going into C on the Digistat though.

Is this correct?

 

[stem]

A bit more information is required.

There are many variants of Drayton Digistat. Is yours purely a thermostat (just temperature control) or is it a programmable thermostat? (Time and temperature control) The model details would assist here.

If it doesn't have time control, what is presently controlling the heating times?

What type of heating system do you have? eg. S Plan (with 2 x two port motorised valves), Y Plan (with 1 x three port motorised valve) Combi boiler without a hot water cylinder.

 

[pcdj]

Sorry, it's a programmable digistat +2 - time and temperature.

This is an apartment block with communal heating, so I'm not sure where the wiring goes - I assume as central valve entering the apartment as we have no boiler.

 

[stem]

Thanks, so the next question is. If it has remote wiring from a communal system, can you isolate the electrical supply to allow you to work on it? Or is it powered from the electrical supply to your property?

Also, the Nest requires a permanent electrical supply. Is the communal system is powered up 24/7? What I mean by this, is if at anytime during the day or night you turned the heating on at the Digistat, would it come on, or are there periods of time when it doesn't work? If it does come on 24/7, then you can use the existing wiring. If not you will need to provide a permanent live and neutral supply for the Nest Heatlink.

 

[pcdj]

At source it's on 24/7.

To the right of the programmer, just out of sight of the picture, is a wall on/off switch to isolate the supply.

 

[stem]

Good. Unfortunately, because the existing thermostat is battery powered, the wires going to the Digistat thermostat are just used for switching and can be inserted either way around. So it's not possible to say for certainty which is the permanent live and which is the switched live.

If I had wired it up, then I would agree with your assumptions and say that you are right, and that the Red and Brown would stay together as they are, and go to the Nest L. It is unlikely (but not unknown) that a black has been used for the permanent Live in this installation, and it is far more likely to be the switched live (heating on) and that the Blue and Grey are Neutrals.

However to be sure, it would be wise to check first with a multimeter.

 

[Dan Robinson]

Thought a sparks was doing this installation?

 

[stem]

Eh????? The OP said

I intend to do as follows...

 

[pcdj]

Thought a sparks was doing this installation?

Checked the warranty situation as was suggested, and it's expired.

 

[pcdj]

Eh????? The OP said

It's in reference to a previous thread.

 

[Dan Robinson]

Checked the warranty situation as was suggested, and it's expired.

Warranty on what?

Without multimeter knowledge I wouldnt be poking around inside your HIU (assuming there is one). What kit does the apartment have to connect to the communal system?

 

[pcdj]

Warranty on what?

Without multimeter knowledge I wouldnt be poking around inside your HIU (assuming there is one). What kit does the apartment have to connect to the communal system?

Warranty on the installation from the builder. (It's a new build but not literally new).

The "kit" is the digistat. That's it.

 

[stem]

The photo shows that the warranty on the Digistat expired over 3 years ago, so I would expect the installation to be over 4 years old.

I hope there isn't a duplicate thread on the same subject somewhere else.

Edit. I have just had a look and there is! pcjd can I suggest that you familiarise yourself with the forum rules please. It can save a lot of time and confusion.

 

[Dan Robinson]

Will also help to give more information about the communal system.

 

[pcdj]

The photo shows that the warranty on the Digistat expired over 3 years ago, so I would expect the installation to be over 4 years old.

I hope there isn't a duplicate thread on the same subject somewhere else.

Edit. I have just had a look and there is! pcjd can I suggest that you familiarise yourself with the forum rules please. It can save a lot of time and confusion.

Acknowledged.

It wasn't quite a duplicate in my mind - the other thread was more about how the physical bits could be placed around the flat, and this one was a follow up for the wiring now that I've purchased a unit.

If that was a wrong decision then apologies; as you can see I'm fairly new here.