Nest Thermostat Gen3 (US) UK installation

[Ozmusafir]

I moved into a Taylor wimpey home early this year. They have the ESI programmer and two ESRTD3. One ESRTD3 controls the heating in the living and the other controls the rooms upstairs. I also have a water tank with
ESRTD3 controlling the water temperature.

Recently I went to the US and brought two Nest thermostat Gen3. Once getting back to the UK, I realised the EU version has a heatlink. I’m unable to purchase the heatlink from Nest as they don’t sell it.

I still want to put the nest thermostat to use, therefore can I simply replace the ESRTD3 controlling the heating? According to research the US version can be connected directly to the 24vac

 

[ericmark]

Finding USA instructions is hard but the utube instructions do seem to be available,

it seems 24 volt AC at least that was written on the thermostat being removed, some UK boilers do have the option of using 24 volt some are AC and some DC not sure if USA Nest will work with DC.

However it seems the USA Nest is designed to work air conditioning and heating, which is often by air ducts not water, so it seems it has no ability to control the DHW. Although it may be possible to get a 24 volt supply either from boiler or from a transformer and use relays, where it all falls down is getting the app for your phone that is matched to USA system and UK.

Nest uses the internet to check on weather conditions, and so clearly needs to be set to UK, but big question is if the USA app can work out UK weather.

So you have.
W1 = Heating.
W2 = Heating second stage.
C = common wire of transformer.
*
RH

Y1 = Cooling.
Y1 = Cooling second stage.
G = Fan.
OB = Heat Pump.
RC = Power wire.

First job is find out what they mean. I have filled in some, but really can't see how your going to make it work with a British system. There was a time when it was hard to find British wiring diagrams on the net, it was always USA ones which came up, but I think you have a door stop, fancy one, but not much chance of getting it to work with a British boiler and British internet.

 

[flameport]

can I simply replace the ESRTD3 controlling the heating?

No.
Your existing system uses 230V AC. The USA Nest thermostat does not.
The USA Nest is totally incompatible with UK heating systems.

 

[muggles]

Even if you could buy a heat link it wouldn't help - the Nest control is a totally different product which would be incompatible with the Heat Link. I really don't think you're going to get the ones you've bought to work over here

 

[Ozmusafir]

Thank you guys.

I decided to dig the plan and buy a Nest Thermostat Gen3 from screwfix.

One small question. My ESI room heating dial is in the living room controlling the heating for the living room. Also on the other side of the wall, there is another ESI dial controlling upstairs. I’m assuming the cables from the ESI programmer come to the dials and I can easily mount the nest thermostat in place of it and power it using the existing wires?