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Hi just bought a nest e thermostat . Ive included a picture of the wiring for the old thermostat and the connections for the new nest thermostat. I just want to make sure it’s compatible before I get someone to install it. Which wire goes to which connector for want of a better question ?

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buzzlightyear

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I just want to make sure it’s compatible before I get someone to install it
I would agree with Tele ,and would agree with your self .
 

Midwest

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Does seem unusual not to have a neutral at an old existing room stat. Someone moved the existing stat in the past?
 
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  • #6
Is N neutral?

Gas was only installed about ten years ago
 

James

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The nest thermostat is a combination of time clock and thermostat.
The base “receiver” unit can be fitted next to the boiler where there will be all the cables that you require.
The control or thermostat unit would normally be placed wherever the old thermostat is mounted and only needs 2 cores. This is to supply power from the base unit to the stat unit, as per the instructions.
All the control signals are sent wirelessly from the stat to the base unit.

Although this could be done by someone good diy skills and electrical knowledge, I would recommend getting a professional in to do it.

A mistake in the wiring could do any of the following.
1. Write off the boiler control board
2. Write off the nest thermostat
3. Cause a shock or other injury
4. All of the above at the same time.

As long as you have a wire with at least 2 cores going from the boiler to the old stat, a professional should have you up and running within the hour.

P.s. for the techs reading this, the only function of the link wire from base unit to stat is to supply 12v dc to the stat for its own power.
 
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  • #9
Hi again, can I just clarify that this is a nest thermostat E that uses the heat link at the thermostat with nothing fitted to the combi boiler itself (obviously the thermostat connects to the boiler at that point). I’ve just spoken to nest tech support and told her that I only have a 2 wire system and she seemed very confident that they will connect to the C and NO and that the system will work.
 

telectrix

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Is N neutral?

Gas was only installed about ten years ago
N is indeed neutral.
Post automatically merged:

The nest thermostat is a combination of time clock and thermostat.
The base “receiver” unit can be fitted next to the boiler where there will be all the cables that you require.
The control or thermostat unit would normally be placed wherever the old thermostat is mounted and only needs 2 cores. This is to supply power from the base unit to the stat unit, as per the instructions.
All the control signals are sent wirelessly from the stat to the base unit.

Although this could be done by someone good diy skills and electrical knowledge, I would recommend getting a professional in to do it.

A mistake in the wiring could do any of the following.
1. Write off the boiler control board
2. Write off the nest thermostat
3. Cause a shock or other injury
4. All of the above at the same time.

As long as you have a wire with at least 2 cores going from the boiler to the old stat, a professional should have you up and running within the hour.

P.s. for the techs reading this, the only function of the link wire from base unit to stat is to supply 12v dc to the stat for its own power.
so, if i read your right. ( bear in mind i have no knowlege of nest), he needs a 3core/E (or 4 core flex) from boiler to receiver, and just a pair to the actual stat., which mus be RF to the base unit?
 
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  • #12
I’ve just found this installation video. Is this not exactly my combination of wires brown, blue and yellow/green

5mins 50 in..

 
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  • #14
Oh , now my head is hurting, I won’t even pretend I understand and now beginning to think I’ve wasted my money , thought this was going to be an easy swap over
 

James

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Nest e is far simpler than the original nest unit.

Download the app, the app will guide you through installation.
All the info is here, watch the video, pause it when you need to do something, then continue.



If you are unsure, get a professional in to assist.
 
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  • #16
Yeah I’m going to get a professional to do it for me, he’s doing it as a favour so I really wanted it to be as simple as possible and that’s why I bought the E . It’s also a housing association property so if it’s going to require a neutral wire installed then I’m probably going to require permission and other red tape before I can go ahead which will probably lead me to just not doing it.

I’m curious to know why telectrix knows it’s a switched live and not a neutral as every website I’ve looked at says neutral is a blue wire. Is it to do with the wiring diagram I uploaded?
 

buzzlightyear

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It’s also a housing association property
have you written permission from them to alter the wiring for the nest .
 
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  • #19
No that’s why I said it would hold things up. I’ve been told if I fit a nest they won’t maintain it and would only replace it with basically what’s in now .
 

buzzlightyear

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most housing associations dont like people playing with their boilers or other things just in case their is a mishap .
 

James

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Yeah I’m going to get a professional to do it for me, he’s doing it as a favour so I really wanted it to be as simple as possible and that’s why I bought the E . It’s also a housing association property so if it’s going to require a neutral wire installed then I’m probably going to require permission and other red tape before I can go ahead which will probably lead me to just not doing it.

I’m curious to know why telectrix knows it’s a switched live and not a neutral as every website I’ve looked at says neutral is a blue wire. Is it to do with the wiring diagram I uploaded?
It’s a switched live because there are only 2 wires being used and the device is a switch of sorts, if it were a neutral, there would be a loud bang when the thermostat switched to on and the heating would not work.
 
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  • #22
It’s a switched live because there are only 2 wires being used and the device is a switch of sorts, if it were a neutral, there would be a loud bang when the thermostat switched to on and the heating would not work.

And the nest system doesn’t work on the same principle?

How easy is it to run a neutral? Does it have to come from the boiler ?
 
Nest Gen 3 needs a neutral, but Nest e does not, it's battery operated only two wires, really simple to install, why people are talking about neutral I don't know.

So 1 and 2 go to C and NO other three terminals are not used. It does not even matter why way around the two wires go. Could you get anything easier?
 
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  • #24
Omg ericmark where have you been finally some good news mainly cos it’s what I wanted to hear. Will anyone else concur with this?
 

James

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Omg ericmark where have you been finally some good news mainly cos it’s what I wanted to hear. Will anyone else concur with this?
If you had installed the app and watched the vid I posted above, it would have told you that, direct step by step guidance is frowned upon here but the app and vid will show you how to do it in a relatively safe manner.
Although I am not keen on the method of proving the circuit is dead before work starts.
 
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  • #26
If you had installed the app and watched the vid I posted above, it would have told you that, direct step by step guidance is frowned upon here but the app and vid will show you how to do it in a relatively safe manner.
Although I am not keen on the method of proving the circuit is dead before work starts.

Yeah that’s the same video I posted just a couple comments before yours, I’ve got the app installed but didn’t want to go thro the steps until it was getting installed in case it didn’t let me go through them again so to speak. So do you agree that it will work with my existing wires?
 
I use Nest Gen 3 and I made mistakes when setting up the software, and it is no problem to return and alter it latter.
 
Yeah I’m going to get a professional to do it for me, he’s doing it as a favour so I really wanted it to be as simple as possible and that’s why I bought the E . It’s also a housing association property so if it’s going to require a neutral wire installed then I’m probably going to require permission and other red tape before I can go ahead which will probably lead me to just not doing it.

I’m curious to know why telectrix knows it’s a switched live and not a neutral as every website I’ve looked at says neutral is a blue wire. Is it to do with the wiring diagram I uploaded?
Because Telectrix is a sparks. So he knows
 
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  • #30
I got the nest thermostat e thermostat professionally installed yesterday using existing wires and nothing more , all seems to be working.

Without causing offence alot of the advice and opinions given on this post were inaccurate.
 

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