Nest thermostat compatible wiring

[Grahalex]

I am thinking about buying a Nest Thermostat, and would like to put it in my hall, where the old honeywell Stat is, but I am not sure if the wiring is compatible. I have attached a photo. Please could someone have a look to see if the Nest can use this wiring.
I have a Viessmann Vitodens 100-W WB1B Regular boiler Open vent. I also have a hot water cyclinder.

 

[Leesparkykent]

I am thinking about buying a Nest Thermostat, and would like to put it in my hall, where the old honeywell Stat is, but I am not sure if the wiring is compatible. I have attached a photo. Please could someone have a look to see if the Nest can use this wiring.
I have a Viessmann Vitodens 100-W WB1B Regular boiler Open vent. I also have a hot water cyclinder.

View attachment 39399

Yes that cable could be used. The heatlink would have to be installed by the wiring centre which is usually next to your hot water cylinder. The cable connecting to old thermostat could be used to power the new nest thermostat so you don't have to plug the nest thermostat into a socket. Do you know what plan your system is...usually a Y or S plan? If you have a Y plan and the switched fused connection unit and programmer is not located near the wiring centre then you may not have a permanent live at the wiring centre...just worth checking before you go ahead and purchase it.

 

[Grahalex]

That’s good news.
I do not know which plan it is. The programmer is next to the boiler.

 

[Leesparkykent]

That’s good news.
I do not know which plan it is. The programmer is next to the boiler.

Is the switch/fused spur next to the programmer/boiler? If it's a y plan you will have 1 three port valve next to the cylinder if it's an S plan you will have 2 x two port valves next to the cylinder.

 

[davesparks]

Yes it will be possible for a competant electrician to do this.

 

[marconi]

Sir, Don't dabble with wiring you don't understand. Electricity kills and causes fires if something is wrong or a fault develops. This is a bread and butter job for an electrician - and he will do the required legal testing after the work and furnish you with a certificate saying all is well. You then rest assured and your insurance company will pay up if subsequently something - God forbid - happens; whereas if you have done the work .....

 

[Octopus]

If you try this and get it wrong, you could easily put 230v into the poor Nest which only needs 12v - then the only place to put it will be the bin.

 

[Grahalex]

Sir, Don't dabble with wiring you don't understand. Electricity kills and causes fires if something is wrong or a fault develops. This is a bread and butter job for an electrician - and he will do the required legal testing after the work and furnish you with a certificate saying all is well. You then rest assured and your insurance company will pay up if subsequently something - God forbid - happens; whereas if you have done the work .....

I am not planning on doing the work myself, but want to make sure that the Nest will go where I want it to before I buy it.

 

[marconi]

I am not planning on doing the work myself, but want to make sure that the Nest will go where I want it to before I buy it.

Forgive me - I misunderstood your opening post.

 

[Grahalex]

If you try this and get it wrong, you could easily put 230v into the poor Nest which only needs 12v - then the only place to put it will be the bin.

From the photo I attached, is it possible to tell if the wiring is 230v or 12v ?

 

[Grahalex]

Forgive me - I misunderstood your opening post.

No problem.

 

[Octopus]

From the photo I attached, is it possible to tell if the wiring is 230v or 12v ?

Thats irrelevent. Its not just about changing the stat. Theres much more to this than meets to eye, and in some cases its not possible.

Only a site visit from a competent person can say for sure.

 

[Grahalex]

Thats irrelevent. Its not just about changing the stat. Theres much more to this than meets to eye, and in some cases its not possible.

Only a site visit from a competent person can say for sure.

Ok, thanks. This is more complicated than I thought, and as portrayed by Nest.

 

[DJ Ovengloves]

The thermostat is battery powered, the receiver that will replace the current thermostat is 230v. You need a neutral and live for it to work....this will need testing and configuring by someone competent.

 

[Grahalex]

The thermostat is battery powered, the receiver that will replace the current thermostat is 230v. You need a neutral and live for it to work....this will need testing and configuring by someone competent.

Oh I see. I thought that the Heat link replaced the programmer. I have a Honeywell programmer next to the boiler, which has an isolation switch next to it. My boiler is 5 years old.

 

[Grahalex]

Is the switch/fused spur next to the programmer/boiler? If it's a y plan you will have 1 three port valve next to the cylinder if it's an S plan you will have 2 x two port valves next to the cylinder.

View attachment 39401

View attachment 39402

I have one port valve, see photo. There is a switch that is fused next to the boiler and programmer.

 

[Leesparkykent]

The nest heat link could replace the programmer but the cable that goes to the thermostat will be at the wiring centre so won't be able to be connected to the heat link. If the programmer and switched fused spur is next to the boiler then you may not have a permanent live at the wiring centre as it's not needed being a Y-plan. An electrician who knows heating will be able make it work.

 

[davesparks]

The thermostat is battery powered, the receiver that will replace the current thermostat is 230v. You need a neutral and live for it to work....this will need testing and configuring by someone competent.

The nest thermostat is not battery powered, it is either powered by a plug in adaptor or a 12V supply from the heatlink.

 

[davesparks]

Oh I see. I thought that the Heat link replaced the programmer. I have a Honeywell programmer next to the boiler, which has an isolation switch next to it. My boiler is 5 years old.

The nest system replaces both the thermostat and the programmer.
However the heatlink will probably not go in the same location that the programmer is in now, usually it will go next to the wiring centre in the airing cupboard.
Your thermostat will almost certainly be 230V currently, but the installer will connect this cable to the 12V terminals of the heatlink for the nest thermostat.

 

[DJ Ovengloves]

Blooming heck...I was convinced the OP said Hive. These Codiene cold pills are awesome!

The nest thermostat is not battery powered, it is either powered by a plug in adaptor or a 12V supply from the heatlink.