ESI Wired Thermostat to Tado Wired - 2 Zones (DATA CABLES)

[J3oef]

Morning All,

I've purchased a new builder and have ESI thermostats upstairs and downstairs which are mains wired. 5V I believe.

I was planning to install the Tado thermostats myself by messing around with the wiring center but would require the chopping of cables. Before I did this I checked the wiring behind the thermostats and have discovered these are CAT5 data cables which halted my progress and I'm not getting an electrician to do it. Although he's never done thermostats before he said so wasn't 100% sure but was going away to do some research.

Anyway, he has come back to me and said he is going to need to run new wires as the cables that have been installed by the builder are CAT5 data cables which cannot run over 240V. Obviously I don't want new wires run as this would mean cutting out channels etc in the newly built house which the wife will not want.

Someone in a similar position to me but with the correct wiring behind the thermostats has suggested using a Shelly 1 Plus relay as a workaround and mentioned it needs to be a dry contact relay so 240V are not going down data cables as that would obviously be a fire waiting to happen.

Would anyone know anything about that as the electrician didn't really take me on when I mentioned it? Or is my only option to run new cables as suggested?

I've added pictures of the wiring and wiring center for reference.

Cheers

 

[RandomGrinch]

Or you could decommission your old stats entirely and use wireless stats (i.e. Tado V3+, Hive, Nest, etc.), with the receivers connected at the wiring centre.

Here are some we've done before...

Replacing ESI ESRTP6C with Nest Thermostat (3rd Gen) - Dual Zone

Hi, I am planning on replacing the two thermostats in my new build house that control the dual zone central heating. The thermostats are ESI ESRTP6C are connected to a wiring system that is connected to the combi boiler and two valves. The thermostats have the following wires connected: +5V...

www.diynot.com

Alternatively, a battery powered stat like a Tado 'Wired' could be used to replace your existing stats, with no wiring changes.

 

[J3oef]

Or you could decommission your old stats entirely and use wireless stats (i.e. Tado V3+, Hive, Nest, etc.), with the receivers connected at the wiring centre.

Here are some we've done before...

Replacing ESI ESRTP6C with Nest Thermostat (3rd Gen) - Dual Zone

Hi, I am planning on replacing the two thermostats in my new build house that control the dual zone central heating. The thermostats are ESI ESRTP6C are connected to a wiring system that is connected to the combi boiler and two valves. The thermostats have the following wires connected: +5V...

www.diynot.com

Alternatively, a battery powered stat like a Tado 'Wired' could be used to replace your existing stats, with no wiring changes.

Hello @RandomGrinch

I have the Tado V3+ and Tado Thermostat currently. I'm led to believe I can use these wirelessly? If so then would I just need the Wireless Extender ?

I plan to add Tado TRVs at some point. Do you see any issues with the above or think having 2 zones will cause a problem?

Thanks

 

[RandomGrinch]

I have the Tado V3+ and Tado Thermostat currently. I'm led to believe I can use these wirelessly?

If those are exactly the models you have, then that is the 'wired' option I mentioned earlier.
Were those the ones you gave to the electrician to install?
As I said, they are battery powered, and can be connected directly to your existing stat wiring.
Have you unpacked them to have a look?

 

[J3oef]

If those are exactly the models you have, then that is the 'wired' option I mentioned earlier.
Were those the ones you gave to the electrician to install?
As I said, they are battery powered, and can be connected directly to your existing stat wiring.
Have you unpacked them to have a look?

Yes, They are exactly the ones I have. The electrician just had sight of the boxes, he never actually opened them.

I didn't think I could connect them to my existing stats as they require 240V and the wiring behind my existing stats is CAT5 data cables.

 

[RandomGrinch]

I didn't think I could connect them to my existing stats as they require 240V and the wiring behind my existing stats is CAT5 data cables.

As earlier, they are battery powered, they do not require 240V.

The blue & blue/white wires would go into NO on Tado.
The orange & orange/white wires would go into COM on Tado.
The brown & brown/white wires would go into P1 on Tado.

 

[J3oef]

As earlier, they are battery powered, they do not require 240V.
View attachment 369184
The blue & blue/white wires would go into NO on Tado.
The orange & orange/white wires would go into COM on Tado.
The brown & brown/white wires would go into P1 on Tado.

What's the idea behind Tado doing a wired and wireless version then? I mean that's music to my ears if the above is all I need to do as I can get it sorted tonight. I've had it 7 weeks and not been able to use it yet.

 

[RandomGrinch]

What's the idea behind Tado doing a wired and wireless version then? I mean that's music to my ears if the above is all I need to do as I can get it sorted tonight. I've had it 7 weeks and not been able to use it yet.

I'm not entirely sure, but traditionally, a simple heating system may only have a two wire stat that was wired into the wall. It would have a live and a switched live.
Without a neutral, it can't power a mains powered stat - hence there are/have been a few battery operated 'wired' stats, i.e. Tado wired, Hive 'wired', Nest thermostat E etc.
With a wireless system the receivers can be mounted where they are convenient, i.e. near the boiler, or wiring centre; places where getting a mains supply isn't a problem.
There are some wired options that do require a mains supply on the wall, but luckily, you didn't choose one!

And I should mention that ESI have gone their own way with their own proprietary extra low voltage system, to try and ensure you keep on buying ESI controls!
They are often found as kits, installed into new-builds to meet part L requirements of the building regs and hence the link in post #2.

 

[J3oef]

I'm not entirely sure, but traditionally, a simple heating system may only have a two wire stat that was wired into the wall. It would have a live and a switched live.
Without a neutral, it can't power a mains powered stat - hence there are/have been a few battery operated 'wired' stats, i.e. Tado wired, Hive 'wired', Nest thermostat E etc.
With a wireless system the receivers can be mounted where they are convenient, i.e. near the boiler, or wiring centre; places where getting a mains supply isn't a problem.
There are some wired options that do require a mains supply on the wall, but luckily, you didn't choose one!

And I should mention that ESI have gone their own way with their own proprietary extra low voltage system, to try and ensure you keep on buying ESI controls!
They are often found as kits, installed into new-builds to meet part L requirements of the building regs and hence the link in post #2.

Well, you know what I'll be doing tonight

Makes sense now you say it regarding a neutral not being present. Had I had the mains wires instead of cat 5 data cables, I assume this is when I would need to mess about with the wiring center which I've come across quite a lot on my forum searches for ESI controls and people wanting to swap them out.

I'll open up the goods tonight and just double check everything is as I've said it was but I'm confident it is. Might be a silly question, but do I need the mains power off when I swap them?

 

[RandomGrinch]

Might be a silly question, but do I need the mains power off when I swap them?

It's best to turn the wiring centre off at the mains (it will probably turn off from the FCU for the boiler).
It's not really for your safety, but to avoid shorting and damaging the 5V power supply on the ESI.

Let us know how you get on, good luck!

 

[J3oef]

It's best to turn the wiring centre off at the mains (it will probably turn off from the FCU for the boiler).
It's not really for your safety, but to avoid shorting and damaging the 5V power supply on the ESI.

Let us know how you get on, good luck!

Do I need to consider whether the switching circuit in/from the boiler is low voltage or mains. My thermostats might not need 240V but the wiring to the boiler could be carrying it?

Edit - This may tell us

https://media.plumbarena.co.uk/uploads/files/2023/03/13/ESRTP6C-Installation.pdf

 

[RandomGrinch]

Do I need to consider whether the switching circuit in/from the boiler is low voltage or mains. My thermostats might not need 240V but the wiring to the boiler could be carrying it?

No you don't.
As...

It's not really for your safety, but to avoid shorting and damaging the 5V power supply on the ESI.

The 'data' cables to the existing stats are carrying an extra low voltage 5V supply.
If you are putting your new stats in the same position, using the same wires as the old stats, you don't need to touch anything in the wiring centre.

 

[J3oef]

No you don't.
As...

The 'data' cables to the existing stats are carrying an extra low voltage 5V supply.
If you are putting your new stats in the same position, using the same wires as the old stats, you don't need to touch anything in the wiring centre.

Sorry for the persistent questions. Just wanted to make sure I'm not going to make it go kaput.

Based on the PDF link above, is 5V going to the PSU/PCB from the stat and then 240V is going to the boiler?

I mean the Tado power requirements state the below so there's no reason as you say to touch anything.

Add on Thermostat - Power Supply = 4.5VDC

Wired Smart Thermostat Stater Kit V3+ = 4.5 VDC (Starter Kit), 5 V USB (Internet Bridge)

 

[RandomGrinch]

is 5V going to the PSU/PCB from the stat and then 240V is going to the boiler?

No, nothing is coming from the stat itself, it is purely acting as a switch.
The stat is powered by 3 AAA batteries, hence the 4.5V.
5V is coming from the power supply at the wiring centre.
The stat closes it's switch, that activates a relay at the wiring centre - only 5V up to this point.
When the relay closes, the zone valve receives 230V to open and that in turn provides a switched live to the boiler.

All you need to do is switch the boiler/wiring centre off and replace the stat following the comments in post #6