NEST install

Hilly · 28 Nov 2015 at 18:30

Hi all - finally purchased a NEST - giving it a go with the installation myself; It's a new build, existing thermostat. Here's a picture (beware big image!):

There's also a grey wire in the background and also the ground (yellow green) which is connected into the wall.

can anyone tell me the correct way to wire this up for a NEST please, e.g which wires go where please?

BigBoy · 28 Nov 2015 at 18:36

What brand is your current thermostat?

Hilly · 28 Nov 2015 at 18:38

It's a Danfoss. Looks like a TP5000~

joelk2 · 28 Nov 2015 at 21:14

easy one this, 2 to nest 2, 3 to nest 3

Hilly · 28 Nov 2015 at 21:40

Thanks for the response. Do I need to do anything with the grey one at the back (which isn't connected currently)? What about the earth? Keep that attached to the inbuilt cage?

Participant · 28 Nov 2015 at 22:14

I thought the Nest needed a transformer in between the thermostat and the boiler? I don't think you can just connect the Nest and that be that.

joelk2 · 28 Nov 2015 at 22:21

Participant said:
I thought the Nest needed a transformer in between the thermostat and the boiler? I don't think you can just connect the Nest and that be that.

heat link connects to the boiler, nest itself either plug in or wire in.

Hilly · 28 Nov 2015 at 23:04

Honestly Participant - no idea; Hence the thread!

Don't really want to bite the bullet and get someone in to do it, would like to do it myself!

RoyMi6 · 28 Nov 2015 at 23:48

What's the script for installing installing a Nest when you've got a combi boiler but no thermostat installed in the house already?

The combi boiler just has it's own built in timer thing on the front (mechanical type) and I've just got a switch that's either "on, off, timer".

Could I still get one?

ZG002 · 29 Nov 2015 at 00:50

You can but you will have to install extra wiring.

Participant · 29 Nov 2015 at 08:00

joelk2 said:
heat link connects to the boiler, nest itself either plug in or wire in.

...to the heat link, not the boiler.

Jez · 29 Nov 2015 at 08:48

Participant said:
...to the heat link, not the boiler.

Ive been looking at changing to one of these systems since i changed the boiler recently and am generally revamping the heating system.

In the case of the nest and most of these systems (cosy, nest, hive, etc) the control unit (heat link) sits where the wired stat would be and mechanically calls for heat as usual.

The actual user interface unit connects to this wirelessly and may be placed anywhere.

ZG002 · 29 Nov 2015 at 09:00

Yeah basically the (heat link) is a switch, which is controlled wirelessly.

Hilly · 29 Nov 2015 at 13:46

Any more opinions on how to wire the nest up as per above?

ZG002 · 29 Nov 2015 at 14:11

What connections do you have on the nest heat link?

Forget the earth as it's connected to the back box, forget the grey.

All you need to do is connect the brown and black to the com and on connections (if that's what they have on nest) take a photo of the nest heat link with connections.

Does the nest heat link need a constant live?

Your current stat runs off of batteries.

BigBoy · 29 Nov 2015 at 15:02

hilly said:
Any more opinions on how to wire the nest up as per above?

What does the installation instructions say for the original stat? That will at least tell you what the wires are for.

Hilly · 29 Nov 2015 at 15:05

I'll try to dig them out; I thought the current one was powered - with the battery only for backup purposes.

Will try to dig out them out now - cheers chaps.

ZG002 · 29 Nov 2015 at 15:37

Nah, your original one is powered by the battery, those two wires are live feed and live return. All the stat does is close the switch between them when it's calling for heat and that brings the heating on.

RoyMi6 · 29 Nov 2015 at 19:20

Does the NEST controller always have to be plugged in? Can I just take it off the wall and have it in the livingroom with me when I know I'm going to spend the day in there rather than the actively doing things around the house - at which point, back on the wall in the hall would make perfect sense.

joelk2 · 29 Nov 2015 at 22:27

RoyMi6 said:
What's the script for installing installing a Nest when you've got a combi boiler but no thermostat installed in the house already?

The combi boiler just has it's own built in timer thing on the front (mechanical type) and I've just got a switch that's either "on, off, timer".

Could I still get one?

yes, this is how mine was set up.

i have to plug my nest into the usb thing though, the heatlink gets hard wired to boiler.