Vaillant Ecotec 838, VRC430 & Nest Thermostat

[jcoles7]

Hi All,

So I have an Ecotec 838 and have a the VRC430 wall mounted.

I would like to have the web functionality of the Nest but believe it has a few downsides.

1) The Nest as far as I know just switches the boiler on/off and does not modulate the burner.

2) The weather compensation is reliant on internet weather so will never be as accurate as the VRC430 with it's external sensor.

3) It is not possible to set a specific heating curve on the Nest

So my question is: Would it be possible to mount the VRC430 in the boiler and use the burner modulation, weather compensation and heating curve selection and use the Nest as the thermostat and programmer ?

I have been looking at the Tado, Evohome and Heat Genius, with the Evohome and Heat Genius you can zone each room with wireless TRVs at a price and the Tado has Geofencing. I understand TRV's are in the pipeline for the Tado. That said I much prefer the styling of the Nest.

Also I have a Nest Protect smoke alarm and my understanding is that when used with the Nest Thermostat if the Protect detects any carbon monoxide then it tells the thermostat to turn off the heating.

Any advice would be appreciated

Cheers

Jason [/b]

 

[Dan Robinson]

You can't mix and match control regimes like this.

If you want Internet function then lose the Bunny controller.

What do you want? Pretty? Or functional?

Nest, unless it adopts Opentherm is a poor substitute for Honeywell Evo... Which doesn't support opentherm here..... Oh the irony

You don't have to use trv to zoom e evo, but it involves a complete rerun of heating pipework otherwise.


Trust me..... there isn't an Evo product not connected to my house.

Also trust me when I say the internet connection thing is purely for showing off/looking a cock. Unless you forget to turn off the hot water for a trip away. But even then.....is it really worth it?

 

[Whitespirit66]

Jeez. I know I'm back from the pub and will appear a dinosaur for saying this - but reading the OP - how did we ever let our lives get this complicated?

Just sayin'.

 

[Dan Robinson]

I hear you dude. ?.... and coming from someone who has a house zoned at room level with weather comp, I think I can officially say " that's saying something"

 

[Dean744PiN5]

First world problems

Untitled

• Dean744PiN5
• 6 Apr 2014
• 1

And here's 1 for parents with babies

Untitled

• Dean744PiN5
• 6 Apr 2014
• 1

 

[Dean744PiN5]

Joking aside op, I like the nest but it will not suit all installations especially yours which has a great setup already and is way more efficient than the current generation of nest stats.
At the end of the day it is still a on/off programmable room stat the only difference is, that it looks cool and programs itself that's it.
And it hasn't got weather compensation capabilities, it just turns the heating on a bit sooner if it's colder outside, it can't modulate flow temp like true weather comp.
stick with the vaillant setup.

 

[jcoles7]

Ok so the Nest won't cut it as pretty as it is, functionality comes first.

We often stay at another property at weekends a couple of hours from home and would like to be able to turn on the heating when we are on our way home to warm the house up. Also during the week we do not return from work at a set time so often the heating has been on too early or not early enough.

So I think we could really benefit from some internet control firstly to save some fuel when we are not there and have it warm when we are there.

I have spoken with Tado support and there kit will modulate the burner so they claim, they also suggested I could still use the VRC to control the heating curve. Not sure what protocol the Tado uses and whether it is compatible or if they have just miss informed me. They also advised wireless TRV's are coming for Tado but can't give an ETA.

We do find we would like rooms at different temp and would like to be able to individually control each room. I was quite involved with the install/conversion from a system boiler to the 838 a few years ago and changing the pipe work to a zoned system would have been quite difficult without renewing all the pipe work as some pipes are behind built in wardrobes and walls and not easily accessible. So I think my best option now is to go for a wireless TRV solution as i'm not keen to rip the house apart.

I have yet to fully research the evohome and heat genius systems as to whether you can set heating curves and if they can modulate the 838's burner.

Lastly does anyone know if Vaillant have a web connected control that's going to be released soon ?

Any further advice would be appreciated

 

[Dan Robinson]

The Honeywell heads are imminent - but they have been since January.


Pretty sure Tado are stringing you a line there too.

 

[ALEC1]

The point about varying room temp is that unless they are thermally insulated from other rooms the warmer rooms just heat the cooler ones, then there are issues about minimum flow rates through boilers when only a small zone calls for heat.

Nest's real value is in the awareness raising capacities of google.,. As said the likes of Vaillant produce as good as you get controls...

 

[ALEC1]

you could also use the holiday programme to run the heating at a lower temperature...while you are away..

Internet connectivity doesn't really offer many benefits to heating as central heating is not really used to give rapid heat ups, which radiant heating does.

the good thing about nest is it will bring forward a long needed profile and debate about heating.

that said interaction with controls, such as a temperature boost or reduction to hot water or heating, does offer a saving potential..

putting something into reduced mode for example when you go out would be useful to have on a phone...

 

[JohnHoward]

A boiler installer has recommended to a friend that she install a Vaillant combi boiler (sorry , don't know which one) plus a Nest thermostat/controller. I cannot find any more recent threads that confirms whether the Nest controller is capable of modulating the boiler. I assume the answer was no in 2014 and is still no in 2016. Can anyone give me a link on this. Thanks.

 

[simond]

The Nest cant, but you can use a vrc470 to provide the modulation and an internet thermostat (Nest, Evohome etc) to switch the 24v link on the boiler.

Not sure why everyone wants to modulate the burner using the stat but there you are. Done a fair number of Evos using the Vaillant weather comp in place.

The likes of evo and Nest can use Opentherm but this is a protocol that only has legs in the Netherlands; it has not been as enthusiastically represented in other markets.

Most boiler manufacturers have adopted their own superior control strategies, but have had to create Opentherm compatibility to sell to the Dutch.

 

[Dan Robinson]

As said - Nest can't modulate the flow setpoint - they have been called out recently as the 3rd Gen was hailed as Opentherm compliant which to everyone and his dog would imply it did just that.

Even when they update the firmware to actually work, it wouldn't do it with a Vaillant without an expensive add on card.

 

[JohnHoward]

simond, Dan, thank for confirming the limitations of Nest and Vaillant together. Simond, the advantages of modulating the burner is that on mild days, e.g. today In London, the boiler can run constantly at a very low heat output (e.g. down to 6kw), with low water temperature and maintain room temperature. And as i understand it the condensor is most effective, therefore boiler most efficient, when the return flow water temperature is low as possible.

I assume the VRT350 thermostat is perfect for this job but the user interface is like using a mobile phone in the 1990's that wasn't design by Nokia (or perhaps the firmware has been improved since 2013).

Dan, when you say 'expensive add on card', is that an OpenTherm bridge? Thanks.

 

[simond]

I understand the benefits of weather compensation, I do this for a day job.

Its just that the boilers modulate anyway. The vrt range are not weather compensated.