Vailliant eloblock 28kw + Nest Thermostat

[Leke Zherka]

Dear all,

I would like to apologize in advance for maybe repeating this question in this forum. Unfortunately i could not find the right thread that answered my question that is why I am addressing you guys and gals once again.

I just recently purchased a Vailliant eloblock 28kw electric boiler heater for my house, and I am interested in knowing if i can connect this unit to a Nest Thermostat. This unit i believe is also know in some other countries as ECOBLOCK, although I am not sure.

Unfortunately where i live, I could not find an English schematics of the unit so bare with me and for the Russian speaking people or individuals with electronic skills please let me know if I could be able to connect this unit and how to connect it if possible to a NEST thermostat.

I will attach also two links/files as how this board looks in reality and the Russian/Polish schematics i found online.

I would be very great-full if someone could help me, and I do apologize in advance If I missed a relevant post on this topic that could have helped me.

Best,
Leka.


(Albania)

 

[JohnD]

Russian

It's not in Russian. It looks to me like Polish.

 

[Leke Zherka]

My mistake, when I tried to translate in Google Translate it showed as Russian.

 

[stem]

"regulator temperature u prostoriji" (Croatian) translates into English as "Regulator Temperature in the Room" and shows a voltage free switch....

....that has a 'bridging link' fitted, which is usually found when a room thermostat is not connected....

.....which to me, all seems to point quite nicely to the connections being for a room thermostat. And, as the Nest is a room thermostat and has a voltage free switch (Terminals 2 & 3)......

....personally I can't think of any reason (but can't guarantee it) why it wouldn't work.

Having said that, I have two comments for you to bear in mind:

1) If there are any external motorised diverter valves that control the water flow to a stored hot water tank or heating zone, as we often have in the UK (Sorry, I don't know anything about heating systems in Albania) then the Nest would usually control them, and they in turn control the boiler. If you don't have any external controls, then this is not a concern.

2) The current capacity of the Nest Heat link switch is limited to 3A (resistive) and 1A (inductive) which is the same as most room thermostats I have seen, and I can't imagine from looking at the size of the terminals and 'bridging link' shown in the photo you provided that it would be in excess of this.

The Heat link also does require a permanent mains supply (230V) to power it connecting to N and L, and the Nest Thermostat requires a 12v supply which can come from terminals T1 & T2 or via a separate plug in power supply.

Edit

It's possible that you may have a different type of Nest Thermostat, an economy version known here as 'Nest E'. It has far less terminals and is battery powered instead of 230V. But apart from that, the above still applies, but the voltage free switching terminals are marked 'C' and 'NO' instead of 2 & 3.

 

[ianmcd]

are you installing this in the UK ? it has 4 x 7KW immersion heaters, I have a customer with an electric storage boiler and it has a total of 9KW, with 3 x 3KW heaters and her electricity bills are over £200 per month, that thing will cost an arm and a leg to install and would need a new electricity supply here probably

 

[Leke Zherka]

"regulator temperature u prostoriji" (Croatian) translates into English as "Regulator Temperature in the Room" and shows a voltage free switch....

View attachment 162019

....that has a 'bridging link' fitted, which is usually found when a room thermostat is not connected....

View attachment 162022

.....which to me, all seems to point quite nicely to the connections being for a room thermostat. And, as the Nest is a room thermostat and has a voltage free switch (Terminals 2 & 3)......

View attachment 162020
....personally I can't think of any reason (but can't guarantee it) why it wouldn't work.

Having said that, I have two comments for you to bear in mind:

1) If there are any external motorised diverter valves that control the water flow to a stored hot water tank or heating zone, as we often have in the UK (Sorry, I don't know anything about heating systems in Albania) then the Nest would usually control them, and they in turn control the boiler. If you don't have any external controls, then this is not a concern.

2) The current capacity of the Nest Heat link switch is limited to 3A (resistive) and 1A (inductive) which is the same as most room thermostats I have seen, and I can't imagine from looking at the size of the terminals and 'bridging link' shown in the photo you provided that it would be in excess of this.

The Heat link also does require a permanent mains supply (230V) to power it connecting to N and L, and the Nest Thermostat requires a 12v supply which can come from terminals T1 & T2 or via a separate plug in power supply.

Edit

It's possible that you may have a different type of Nest Thermostat, an economy version known here as 'Nest E'. It has far less terminals and is battery powered instead of 230V. But apart from that, the above still applies, but the voltage free switching terminals are marked 'C' and 'NO' instead of 2 & 3.

Sorry for the delay on my response.

Thank you very much Stem for your very helpful response.

I was able to open the heater and found a different PCB from the one posted earlier.

As you can see it is a little bit different from the schematics found online.

Below is also a photo of the schematics from its original manual:

A more detailed photo of the terminals:

I would really appreciate if you can give me insights as to how you would install the Nest to this device Stenm.

Thanks in advance.

are you installing this in the UK ? it has 4 x 7KW immersion heaters, I have a customer with an electric storage boiler and it has a total of 9KW, with 3 x 3KW heaters and her electricity bills are over £200 per month, that thing will cost an arm and a leg to install and would need a new electricity supply here probably

I am installing this heater in Kosovo, its a new home with proper electrical installation. Costs per kwh here are around 6.9 euro cents, hopefully won't electrocute me by the end of the month.

 

[ianmcd]

wow wait till you get you electricity bill

 

[Leke Zherka]

wow wait till you get you electricity bill

 

[stem]

I was able to open the heater and found a different PCB from the one posted earlier.

In that case the terminals for the Room Thermostat [RT] are those marked RT24V. The red link is removed when the thermostat is connected.

They would go to the voltage free Nest Heatlink switch via terminals '2' & '3' or 'C' and 'NO' depending on which version of the Nest Thermostat you have. It doesn't matter which way around they are connected.

 

[Leke Zherka]

In that case the terminals for the Room Thermostat [RT] are those marked RT24V. The red link is removed when the thermostat is connected.

View attachment 162066

View attachment 162067

They would go to the voltage free Nest Heatlink switch via terminals '2' & '3' or 'C' and 'NO' depending on which version of the Nest Thermostat you have. It doesn't matter which way around they are connected.

Thank you Stem very very very much.

Apart from this I would also need to ling the N, L, Ground , which it doesnt matter from where in the PCB right?

Once again thank you, and I apologize to the community if this is a repeated thread.

Thnak you Stem.

Cool name btw. ScienceTechnologyEngineeringMath

 

[stem]

The Heat link does require a permanent mains supply. In the UK that would normally come from the same 3A fuse that supplies the (gas) boiler. Your installer would know how to get a suitably rated / fused supply to it based on the proscribed wiring practices for Kosovo. If you were to connect the thin wires from the Heat link N & L directly to the main supply for a 28kW boiler, the fuse would be far too large to provide sufficient protection in the event of a fault.

There is an earth terminal at the Heat link. However, the Heat link instructions state that it only requires connecting if terminals T1 & T2 are used to power the remote thermostat.

Having said that instead of leaving the earth wire floating around, I always connect it there, whether the T1 and T2 are used or not.

Don't worry about this being a repeated thread, I had never heard of a "Vailliant eloblock" before this thread. Electric boilers are almost as rare as hens teeth in the UK. I have only ever seen one. As you will have gathered from previous posts, this is due to them costing about 3 times as much to run as a gas boiler connected to the mains gas supply that is available to the majority of us. In more remote areas where mains gas isn't available, oil or LPG tend to be used as they are still cheaper than electricity.

I have used 'Stem' for over 15 years, before the 'ScienceTechnologyEngineeringMath' acronym appeared in common use. It comes from when I worked for a North American company. They took a certain combination of letters from our first name and family name (unless it spelled something rude, in which case they changed it) to form the first four letters of our email addresses. So, I became [email protected] a while we even started calling each other by our acronym's..... so nothing to do with 'ScienceTechnologyEngineeringMath'.....But don't tell anyone.

 

[ianmcd]

@stem I have seen a few electric boilers but the biggest was 12KW, wouldnt like to pay the leccy bill on a 28KW

 

[stem]

The one I saw was I think about that size. It was a Heatrae Sadia installed in a small mid terrace fisherman's cottage that had been converted into a holiday let and located on a narrow street that prevented tankers delivering LPG or oil. No idea of the running cost as I never met the actual owners, but I can't imagine it would be cheap to run in such an old property. It even had single glazing.

I notice now though that more and more new properties, especially flats / apartments with an EPC of C or above are being built with electric panel heaters installed.

Maybe electricity is cheaper in Kosovo.

 

[Gasguru]

Plenty of cheap coal in Kosovo so the electric price is similar to what we pay for gas here...

I'm not so sure about that design...talking to design engineer the other day (that specialises in switching high current elements) suggested using just relays is flawed.
Far better to use triacs to do the initial switching and breaking and only use the relays to hold the elements on...of course that wouldn't create a nice profit in replacement boards.
It's not easy to replace the relays on Vaillant boards...with plated through holes and a very tight pin fit making it almost impossible to remove them without destroying the tracks.

 

[Gazarch]

Hi All,

It seems that the originator of this thread died in June 2019.
I was searching for some technical info as I want to buy the same electric boiler. When I saw his name, it sounded familiar so a quick search revealed that he died on 15 June 2019.
https://ballkani.info/vdes-leke-zherka/
Never knew him but I read he was a well established journalist in Kosovo.

May he rest in peace.

Gaz