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

[J3oef]

@RandomGrinch Sorry to keep asking but I am getting conflicting information which is making me not want to do anything incase it then costs me more to rectify. What is the worst that would happen should I do it and it not work? Just put it back as was?

Someone said --> There is definitely 240V at the stats. The ESI uses low voltage switching as described but the Tado's are 240V. It even says it on the box and my volt meter says the same. All the batteries are for is the display, it's the 240V that is used for switching. He is right in what he is saying that ESI is using low voltage switching at 5V but Tado doesn't so it wont work.

 

[RandomGrinch]

Someone is misinformed.
They either have a different Tado, different wiring, or don't know what they are talking about.
Again - the Tado 'wired' is a 4.5V, battery powered smart stat that operates a relay with 'volt free' contacts.
From it's 4.5V DC supply, it can not magically put 230V AC on its outputs.

If you don't feel comfortable changing the stats, then don't.

 

[J3oef]

Someone is misinformed.
They either have a different Tado, different wiring, or don't know what they are talking about.
Again - the Tado 'wired' is a 4.5V, battery powered smart stat that operates a relay with 'volt free' contacts.
From it's 4.5V DC supply, it can not magically put 230V AC on its outputs.

If you don't feel comfortable changing the stats, then don't.

I'm comfortable changing them.

What is the worst I can do if it didn't work?

 

[RandomGrinch]

What is the worst I can do if it didn't work?

The worst that can happen is you could risk damaging the 5V power supply on the ESI wiring centre (not a big issue).
Turn the power off to the wiring centre/ boiler first and that will avoid the problem.

If you want to perform a quick, risk free experiment to prove to you how the system works - (with the power isolated) simply connect the blue/blue white and orange/orange white wires together - i.e. move the blue wires from 0V into the RH terminal to join the orange wires, on the rear of one of your existing stats.
With the power restored, that heating zone should come on, without the stat operating.

 

[J3oef]

The worst that can happen is you could risk damaging the 5V power supply on the ESI wiring centre (not a big issue).
Turn the power off to the wiring centre/ boiler first and that will avoid the problem.

If you want to perform a quick, risk free experiment to prove to you how the system works - (with the power isolated) simply connect the blue/blue white and orange/orange white wires together - i.e. move the blue wires from 0V into the RH terminal to join the orange wires, on the rear of one of your existing stats.
With the power restored, that heating zone should come on, without the stat operating.

Will give that risk free test a go later on then

I think Tado don't help as they have the 240V warning on the back of the themostats!

 

[RandomGrinch]

I think Tado don't help as they have the 240V warning on the back of the themostats!

Yes, it could seem a little misleading, but if they didn't warn that the back panel could have 230V on it (fed from the boiler/wiring centre/programmer etc.), then that may cause it's own issues.
And note that the warning is on the backplate, and not on the Tado itself.

The markings on the back of the Tado give the supply voltage as 4.5V DC.
The other markings relate to the maximum switching voltage and current.
I.e. 230V AC @ 3A for a resistive load and 1A for an inductive load.
DC voltage can create arcing in the contacts, so the maximum DC voltage is only 30V.

 

[J3oef]

Yes, it could seem a little misleading, but if they didn't warn that the back panel could have 230V on it (fed from the boiler/wiring centre/programmer etc.), then that may cause it's own issues.
And note that the warning is on the backplate, and not on the Tado itself.

View attachment 369265
The markings on the back of the Tado give the supply voltage as 4.5V DC.
The other markings relate to the maximum switching voltage and current.
I.e. 230V AC @ 3A for a resistive load and 1A for an inductive load.
DC voltage can create arcing in the contacts, so the maximum DC voltage is only 30V.

Explained like that makes it easier to understand. ESI list there's as similar by the looks of it.

 

[RandomGrinch]

ESI list there's as similar by the looks of it.

Yes, but that may confuse you, as there is the mains input to the ESI wiring centre a built in PSU for the 5V controls and relays for motoring the zone valves.
I drew out the schematic for the wiring centre in the earlier link - but again, if you're only putting the new Tado in exactly the same place as the existing stats, without changing the wiring; you really don't need to worry about anything in the ESI wiring centre.

 

[J3oef]

Yes, but that may confuse you, as there is the mains input to the ESI wiring centre a built in PSU for the 5V controls and relays for motoring the zone valves.
I drew out the schematic for the wiring centre in the earlier link - but again, if you're only putting the new Tado in exactly the same place as the existing stats, without changing the wiring; you really don't need to worry about anything in the ESI wiring centre.

Ok fair enough. I only ask as I was told ESI don't use simple No/Nc signals but rather a proprietary data bus system which is why simply swapping the wires/stats wont work.

It's not my field so I wouldn't know for sure what you can/cannot do.

 

[RandomGrinch]

I only ask as I was told ESI don't use simple No/Nc signals but rather a proprietary data bus system which is why simply swapping the wires/stats wont work.

They may do on other stats, but with this wiring centre - if you follow the schematic of the PCB I drew out - a 0V connection to RH will operate the relay. There is no additional electronics on the wiring centre PCB, to interpret any proprietary data.