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Using a Nest Learning Thermostat with an Air to Water Heatpump ( Joule & Samsung )

Community Member


I have recently moved in to a new home that is very energy efficient and has an air to water heat pump heating system.

A large boiler ( for radiators and hot water, Joule branded ). It is connected to an external Heat Pump unit ( Samsung branded ) - the wiring unit and controller is also Samsung branded, so I guess it's a Samsung system?

The home has a radiator in each room and has two heating zones ( upstairs and downstairs ) with two corresponding thermostats ( again, Joule white labeled, but potentially something else ) that allows adjustment of temperature ( but nothing more ).

There is also a seperate control on the boiler for the hot water temperature.

Has anyone any experience with installing a Nest Learning Thermostat with these types of systems ? - for one its high voltage so I have to use the Home Link device that comes with it to connect it up. The wiring to each thermostat containts a live, neutral and earth and is about 230v as well as another unlabled black cable which I can only assume goes back to the boiler. I don't even know where to start!

The Google Nest compatability matrix states that it works with heat pumps generally so I thought I would be okay.

Thank you in advance!




Community Member

Hi. I have the very same situation. Did you ever sort it out and have the Nest thermostats installed?

Community Specialist
Community Specialist

Hey folks,


Thanks for reaching out here in the Google Nest Community.


I'd like to jump in here and check if you're in the US or not as it seems to be a high voltage unit that you're trying to install a Nest Thermostat with. Also, you could include a photo of your current wiring configurations for us to further assist you.


Check out this link to know more about Nest Thermostat compatibility with HVAC systems.


Best regards,


Community Member

What made of the thermostat and model of the heat pump do you have?

Community Member

we have same system and would love to know if any solution. We are in ireland

Community Member

Picture of current setup would definitely hrlp

Community Member

I’d happily take a picture but I’m not entirely sure what to photograph? Our tank is inside a large enclosed unit bit the front does come off to expose the tank.

Community Member

Picture of thermostat controller on the wall. The one that wired to the tank. Also the wiring behind the controller. Do you know made and model of the thermostat?

Community Member


 we have 2 of these one upstairs and one down,



Community Member

Is there one next to the tank?

Community Member

Yes. Overall, there are three controllers - two Joule thermostats (like this) and one Samsung-branded on-the-boiler controller (Just like this one).

By the way, I'm also on the same boat - a newly built home in Ireland with Samsung-Joule air-sourced heat pump, with two heating zones (up and downstairs) defined. I very much want to switch to Nest thermostats for better smart features and more control over the heating schedules. Any help would be very much appreciated.


My thermostats are different as show in previous comment but my Samsung control on the tank is exactly as show here by @chandanv89 

Hi Chandav,

I've a Joule/Samsung heat pump system, with 2 zones and DHW.

My house was built in 2021 and has a Joule Kodiak board below the main Samsung controller/distribution board (behind the grey panels on the tank)

I'm no PRO but I did set up a Gen 3 Nest thermostat today and it is working! If I can be of any help let me know!



Hi GK, can you please share the picture of the wiring in the boiler and thermostat please. 

Community Member

I have the same controller and Joule. Do you have the installation manual there? There should be a page mentioning about control board. It should show few examples of the thermostat connection.

Community Member

Basically tandem Joule and Samsung can be easily married to Nest Thermostat, in my case, I have two different zones (first and second floor) where on the wall has been installed Joule thermostat, each thermostat has been connected to the 2 port motorized valves and control those valves based on the desired temperature that set up on thermostat. So you need to figure out your set up and find wiring that control Valves (should be Live (brown) wire on the wiring box that affixed to Joule tank





Once you find those, you need to following Nest wiring diagram for district heating with electrical control valve








And reconnect all wiring accordingly (live to live, neutral to neutral), install jumper between Live and common (port 2) and install Live from valve to call for heat (port 3). Ports 1 to 3 responsible for heating, ports 4 to 6 for hot water and won’t be used in this set up, as hot water controlled by samsung module.





T1 and T2 will be used if you want to install Nest thermostat on the same place where is old thermostat and it will give 12V power to Nest thermostat, if decided to install nest somewhere else, just leave those empty.


In my opinion, you won’t have all benefits that Nest can provide, as Air to Heat pump is more efficient if it’s running all the time and keep temperature in house at the same level (in my case, for example, to heat house from 20 to 24 degrees, it would require from 4 to 5 hours, don’t know why, maybe weather compensation is set up incorrectly). So replacing existing thermostat to Nest, will cost you fortune and you will have a fancy thermostat that can show you time and weather plus you could remotely use it.


Also, if you have two zones (first and second floor floor) you will need two nest thermostat and two heat links.



Thank you for very helpful answer.

Community Member

Hi All,

Just in case it helps any of the users here with a very new Joule/Samsung Heat Pump System(generally Ireland/UK). I have added a Google Nest Gen 3 Thermostat to control one of my zones now and below is how I did it.

I have 2 Joule thermostats(Upstairs/Downstairs) as below:


And this is the tank and Samsung Controller:



This is how the thermostat was wired:


From Left to Right its Switched Live, Neutral, Live. This is a 230V supply.

This is the tank behind the casing(Sorry I had removed 1 wire at this point before taking a picture):


The each thermostat was essentially acting as a switch for the valve for its zone. The main board can essentially be disregarded only the smaller Kodiak board controls this.

In the below picture the red, yellow and blue show where the wires from my thermostat connect to the Joule Kodiak board, the Live is the Yellow arrow, the neutral the blue arrow and the S/L(switched live) the red arrow.

By tracing the wires from my motorised valves which were labelled(thankfully), I found the black wire went from the "Down" valve to the port at the bottom of the board labelled "Zone 2" . For this reason I knew that the switched live I was interested in was "Zone 2" (holding this wire in the photo). It is printed to the left of the connector on the board(to the left of red circle below)


I connected the L/N terminal on the Heatlink to the L/N on the Joule Kodiak board (Yellow Arrow, Blue Arrow). Then I wired from port 3 on the Heatlink to the S/L for the downstairs motorized valve(red arrow).

I also install the jumper between the live and the common(port 2) as in @Snarkzzz post below and as in the official install documents.

As @Snarkzzz mentions, you can use ports T1 and T2 to power your thermostat. I used the Live and the Neutral wires from my original wiring to my thermostat. I made the Earth wire safe and then connected Live to T1 and Neutral to T2 on the Heatlink, and then at the wall downstairs I did the same, Live to T1 and Neutral to T2.

I'm not a Pro but this might be useful for anyone wanting to add a bit of smarts to a Joule/Samsung Air to Water Heat Pump.


I have the same one, can you please share before and after installing the nest thermostat 

Hi @Shanm ,


As I have it installed now I can't get any more before photos other than the ones I uploaded already, sorry!!


Do you want to take clear photos of your setup and if I can help I'll do my best?


Just remember it's electricity so be careful and turn off at Consumer Unit & Switch to be safe! 


Also I won't be able to respond quickly, make sure you know how to put it all back together in case I'm not back to you quickly enough to help!


I'll try get a bit of time to take off the panels again tomorrow and get some after photos.






I have the exact same configuration in my house but I'm not fully sure if there is really much advantage installing Google Nest with a heat pump system.

Would you mind sharing your thoughts on this? If you noticed some improvement in energy bills and day-to-day use?




Community Member

I got 500 Euro bill for last 2 months (jan and Feb). it doesn't include 200 euro credit.

Temperature maintained 24 degree celcius