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Vaillant Ecotec 838, VRC430 & Nest Thermostat

Discussion in 'Plumbing and Central Heating' started by jcoles7, 5 Apr 2014.

  1. ChewChew

    ChewChew

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    They do indeed. However, the Vaillant weather compensator varies the flow temperature unlike the digital on/off weather compensators which means, as John stated, the boiler will operate at as low a flow temp as possible to maintain the required room temp thus improving the efficiency of the boiler.
     
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  3. simond

    simond

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    So what is a digital on off weather compensator then? These DIY forums are an education.
     
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  4. ChewChew

    ChewChew

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    Sorry, I may have got my terminology wrong there or misunderstand weather compensation from other suppliers controllers. As I understand the Vaillant compensator can communicate with a Vaillant boiler fully over eBUS so it can request different flow temps. A third party compensator will only signal demand for heat - on/off which I like to call digital compared to the Vaillant varying or analogue control.
     
  5. wannocks

    wannocks

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    The 430 and 470 are weather compensators.
     
  6. JohnHoward

    JohnHoward

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    Simon, you are right, the VRC470 with weather compensation is a better choice than the VRT350. Didn't know about it even though it's in the thread title (and it's not my day job). But when you say the 'boilers modulate anyway', if the vrc470 does not know both the room temperature or the desired room temperature, how would it modulate the heat output? Or are saying that the user would set the room temperature on the vrc470 and set the heating times on the nest, pretty confusing for the user. You have also mentioned using vrc470 plus evos - surely this is another two controller solution? thanks in advance.
     
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  8. The831Bunny

    The831Bunny

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    Why not use the Vaillant vSMART? Connects to eBus, modulates heating from local weather and room temperature, Internet access, job done. You do need a VR65 to operate the zone valves though which you would have if you had a 430/470 anyway.
     
  9. simond

    simond

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    You set the Vrc to constant heat on, then turn it on and off with Evohome. The vrc does the weather comp variable rad temp bit.

    The thing all you Google jockeys are missing is the heat loss. You are only heating buildings because they lose the heat to outside.

    If I said I have invented something that will cut down boiler energy consumption by 30% you would be interested.

    If I said I had invented something that would cut down consumption by 5% you would be less interested.

    Evohome does the former. Weather compensation modulated boilers do the latter, in mild weather.

    Both can be controlled via the internet, but that is one of those things that everyone gets excited about but is of little real value. Internet control has been around for years, we were doing it with Hometronic 10 years back and it is nothing more than mildly useful.

    So, what do the clever internet stats do? Virtually nothing, buy one and see. They are as clever as turning the porch light on and off from your phone - except a closer analogy would be that they turn every single light in your house, on and off at the same time; because that is what they are doing to the radiators.
     
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  10. pezlaa

    pezlaa

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    Just a quick question for someone....

    I have a Vaillant EcoTech 637, a VR65 control centre and a VRT392f Wireless thermostat. Its a system boiler with hot water tank. I am told the boiler isnt an OpenTherm. I have two zones, but obviously due to the VR65 only have a single zone output, they are wired together on the junction box and therefore act as one zone.

    Can I use this boiler / control centre with a Nest 3rd Generation (so I can control the rads and water tank) Vaillant seem to think "no", as the Nest wont modulate the boiler and I will loose efficiency and it wouldnt control the water ?!!?

    Can someone explain what part of my setup does the modulation and controls how much gas the boiler feeds on and why the Nest wouldnt be suitable. I am not sure if Vaillant are telling porkys or not.

    As for the Nest - has anyone had this style of setup (VR65 etc...) working with a nest.

    Does my 392f just turn the boiler on or off...?

    I am led to believe that the VR65 will need to come out and some sort of 3rd party wiring centre put in.... Any suggestions?

    I would be tempted to move to the VSmart setup from Vaillant. I have struggled to find from the Vaillant website actually what bits and bobs I would need to install this setup. Will it work with my VR65? Or do I need another control centre?
    If I get another control centre, can I get one that I can split my ones into two? If I split my zones into two, can I have two VSmart thermostats - one per zone.

    Oh the questions..... too many questions.

    Thanks everyone
     
    Last edited: 4 Feb 2016
  11. ncwtal

    ncwtal

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    Firstly, I'm sorry if people have already mentioned this in the thread, but I've failed to pick up on this.

    I've bought a Vaillant 837 ECO Plus boiler and was looking at buying NEST, but after reading this thread I've decided against it and now the search continues....
    The trouble I have, is that I've just renovated my house and I really don't want to start chipping into the fresh plaster and running cables to power the wireless stat and the wife has Rynaud's Syndrome, so keeping the house wamr is a must. I'm hoping there's a mains powered stat I can get that works with my boiler, so I can simply just plug this
    I'd love the Honeywell products, but at that price I can't seem to justify it, so the VRC470 is better suited, but I can't find any information on this product relating to main connectivity, so is this possible, or what would you recommend in my situation?
     
  12. ChewChew

    ChewChew

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    Go for the VRC470F which is the wireless version & runs on batteries so you wouldn't need to chase any wiring into the walls.
    Have a look at Vaillant www they do have manuals online which may help with your decision.
     
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