• New Patreon Tier and Early Access Content available. If you would like to support AVForums, we now have a new Patreon Tier which gives you access to selected news, reviews and articles before they are available to the public. Read more.

HELP! Have I brought the wrong Nest??

Hello.

Purchased a NEST thermostat from the recent Amazon prime event.

I only thought there was one version...however on looking at various youtube videos today I seem to have a completely different wall mount to what people have on there...?

I've only got a T1 and T2 cable option where as my current honeywell thermostat has 4 cables going in to it!!

Apologies I appreciate there's a proper subsection for this stuff but wanted some help ASAP whilst the powers off!!

Thanks
IMG_5848[3228].JPG
 

Barry_

Distinguished Member
No mate you haven't brought the wrong one (well if u live in UK that is) Most of the YouTube videos you have probably seen are USA ones and they have the different wall mount with all the wiring connections built in. They don't get the nest heat link the UK does which is what we wire up to the boiler
 

Barry_

Distinguished Member
The back plate of the thermostat takes a 12v connection from the nest heat link terminals with the same T1 & t2 terminals.
 

RBZ5416

Distinguished Member
Thanks guys - no I'm in the UK.

So what do I wire to t1/2 please don't tell me I have to physically run a cable from the heat link??
You disconnect all the thermostat cables from the existing controller or wiring block & then use two of them (red & blue seem obvious) to connect T1 & 2 on the Heatlink to T1 & 2 on the Nest stat. So you're using the existing cabling to provide power to the new stat.

Or you place the 'stat somewhere else & power it from the AC adapter instead.

I have Hive so unfamiliar with Nest but you may have to insert a short in place of the thermostat at the wiring block/Heatlink.
 

Barry_

Distinguished Member
Well if ur current thermostat is in a rubbish place (mine is, they usually are just power it using the plug and usb cable in the room you actually want the thermostat to be.

If the same place then u need to check the current wiring to the old thermostat and see what u got.
 
I hope your statements contain more detail... :D

I've got the heatlink wired up and the boiler powers on etc I've removed the old honeywell thermostat with the four cables one obviously being the earth and tried connecting them in all combo's to the T1/T2 connectors but the nest thermostat is saying no power :-(
 

Cocksure

Well-known Member
the colour coding of the cables is as follows
Red live from boiler
Blue neutral from boiler
Yellow switch live to turn boiler on
yellow/green is earth

Ive never fitted a nest, but if you provide a link to the install manual i should be able to tell you how to wire it pretty quickly
 

Barry_

Distinguished Member
I've got the heatlink wired up and the boiler powers on etc I've removed the old honeywell thermostat with the four cables one obviously being the earth and tried connecting them in all combo's to the T1/T2 connectors but the nest thermostat is saying no power :-(
Hope u used a volt meter first because if you didn't and you wired 240volts to it then u have just fryed the thermostat base and broken it for good.
 

Cocksure

Well-known Member
Hope u used a volt meter first because if you didn't and you wired 240volts to it then u have just fryed the thermostat base and broken it for good.
If he has and is lucky it will have taken out an internal fuse in the boiler, if he's very lucky then there will be spare fuse underneath the wiring cover of the boiler. Or taken out the main boiler fuse of course or the rcd.... All depends if the boiler is still working
 

its_all_Greek

Distinguished Member
Where is the other end of the cable from the thermostat connected to?

It should be only using 2 of the cores and be connected in the heatlink.
 
If he has and is lucky it will have taken out an internal fuse in the boiler, if he's very lucky then there will be spare fuse underneath the wiring cover of the boiler. Or taken out the main boiler fuse of course or the rcd.... All depends if the boiler is still working

Boilers still work the heat link is powered and working with a blue flashing light. The nest thermostat has a green flashing light on the top but won't switch on even if plugged in
 

Cocksure

Well-known Member
Boilers still work the heat link is powered and working with a blue flashing light. The nest thermostat has a green flashing light on the top but won't switch on even if plugged in
hopefully nothing damaged then :)

Ive never fitted one, but if you give me the model number etc i will happily take a look at the manual to confirm the wiring
 
Last edited:

its_all_Greek

Distinguished Member
nothing damaged then :)

Ive never fitted one, but if you give me the model number etc i will happily take a look at the manual to confirm the wiring

You can google it there is 2 wires that connect to T1 and T2 at both the heatlink and the nest base unit purely to power it up.
 

RBZ5416

Distinguished Member
You disconnect all the thermostat cables from the existing controller or wiring block & then use two of them (red & blue seem obvious) to connect T1 & 2 on the Heatlink to T1 & 2 on the Nest stat. So you're using the existing cabling to provide power to the new stat.
You did disconnect from the controller/wiring block first? If so it's as above, the Heatlink provides a 12V output on it's terminals T1 & 2 & you use the disconnected wiring to connect those to T1 & 2 on the stat.
 

The latest video from AVForums

Guardians of the Galaxy Xmas Special, Strange World, Bones and All, and Cabinet of Dr Caligari in 4K
Subscribe to our YouTube channel

Full fat HDMI teeshirts

Support AVForums with Patreon

Top Bottom