Information on Vaillant Ecotech pro 24 in relation to fitting Nest 3rd gen

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Hi all,

I am trying to find out about the Echotech pro 24 as I'm considering getting a Nest thermostat 3rd gen.
Many threads here have dealt with the wiring of various Vaillant boilers and I was wondering whether the wiring would be pretty generic between the models enough to use those threads.

Also there appears to be only one Nest available now days and I am told that there may be an issue with 2 channel thermostats if the boiler does not use 240v ac switching as opposed to 24v dc.

If anyone can tell me if the boiler in question does or doesn't have this and if I get the Nest 3rd get will I be able to follow the diagram provided on this page?

https://www.diynot.com/diy/threads/installing-a-nest-to-a-vaillant-turbomax.425632/page-5
 
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Not sure why you have posted a link to a post about a Vaillant Turbomax, that's a different boiler. In the same way that a Ford Ka is not a Ford Focus. Anyway, the manual I have for the ecotec pro, shows that it is suitable for 24V or 230V thermostats

eco tech.JPG


But you should check the manual supplied with your boiler, yours may not be exactly the same, Vaillant do change things from time to time.

However, having said that, it isn't really that relevant, the Nest Heat link has 'voltage free contacts' so will switch 230V or 24V (aka Low voltage) whatever it is connected to it. The diagrams below show the two ways of wiring it according to the voltage.

NEST.jpg


If to access the boiler terminals, it means that you need to remove a room sealed cover, then that is not a DIY job and should be done by a Gas Safe engineer who can make sure it is correctly sealed up again afterwards.
 
Thanks Stem,
The reason why I posted the link was because my initial question was whether the wiring for Vaillant boilers was generic. I provided that as an example.

I'm pretty sure I have the manuals for the boiler somewhere, it's just a case of digging them up and I will do so before doing anything for sure.
Thank you for the detail on the Nest, I am also looking at the Hive as (I'm not sure I'm comfortable with another Google device collecting data), but Hive has 2 clearly separate models for single and dual channel and I'd have to look at how those connect if I go that way.

Regarding 'room sealed cover' this isn't the case as the engineer who serviced my boiler showed me the block and where to access the terminals for the wired thermostat - they are exposed and accessible by dropping the front panel down.
From what I remember they looked very much like the picture in the link I provided.
 
I thought the ecotec pro didnt have a front flap like the ecotech plus, and the only way to get into the wiring was by removing the combustion cover.
 
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I am also looking at the Hive as (I'm not sure I'm comfortable with another Google device collecting data), but Hive has 2 clearly separate models for single and dual channel and I'd have to look at how those connect if I go that way.

The Hive Single Channel version is for combi boilers and only provides control of central heating. This version has 'voltage free' contacts which can be used to switch 24V or 230V.

The Hive Dual Channel version as the name suggests has a second channel for the control of systems with stored hot water (ie a hot water cylinder) Because these types of systems use motorised valves for control instead of being wired directly to the boiler, the contacts are not 'voltage free' and are connected internally to 230V
 
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Many thanks for the info Stem that gives me the option for either system.
 
I thought the ecotec pro didnt have a front flap like the ecotech plus, and the only way to get into the wiring was by removing the combustion cover.
That's true - the top cover has to be removed then there is a drop down panel to access the wiring.

I opened it today to check:

I am presuming the black / grey wires going to 3 & 4 on the block are from my existing (non - wireless) thermostat
 

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Many thanks for the info Stem that gives me the option for either system.

If you go for Hive, you should go for the Single Chanel version for a Combi that doesn't have hot water control. The voltage free contacts are suitable for 230V or 24V.

I am presuming the black / grey wires going to 3 & 4 on the block are from my existing (non - wireless) thermostat
That is correct for your version of the Vaillant. Terminals 3 and 4 are shown below with a link (i.e. no thermostat fitted) hence why I said check the manual that came with your boiler.

aa.JPG
 
That's true - the top cover has to be removed then there is a drop down panel to access the wiring.
That cover is the room-sealing cover which should only be removed and replaced by Gas Safe Registered Engineers
 
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