J1mbo

Vaillant VR33 with Arotherm Plus

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Any ideas if the VR33 could be used to connect third party smart system via Opentherm to the Arotherm Plus series.

 

The goal is to get variable flow temperature to provide faster heating while minimising average system flow temperature, hence maximising efficiency.

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Did you install an arotherm plus? I have a quote for a 7kw system. I was surprised by the cost of installation at roughly 6k for maybe two days work. Feels like RHI is creating a lot of fluff in prices. Anyway there is not a lot of info on these new units in forums or YouTube yet. How do you find yours? Is it quite when running? The scop looks good for these units, have you found it efficient? Thanks

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On 17/11/2020 at 13:06, J1mbo said:

Any ideas if the VR33 could be used to connect third party smart system via Opentherm to the Arotherm Plus series.

 

What did you do regarding integration in the end?   Vaillant talk about support for EEBus and Modbus using their newer controllers, but I can't find documentation anywhere.

 

Also, our installer has told me that the controller supports 3rd-party "call for heat" but doesn't support 3rd-party "call for cool". 

 

Plans is to use Loxone for all heating control, and there want Loxone to send "call for heat" and "call for cool" to the ASHP controller (either via API, EEBus, Modbus or digital output).

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@Dan F - the system is built around ebus. Vaillant do provide the vr920 Internet gateway option but there is no published API.

 

But, I would think carefully before going 3rd party controls. The system is designed o work with the vr700 which provides the flow curves based on outside, inside, and set point. Without this control the system will need to always be set to a higher flow temp to achieve an acceptable warm up period and hence the efficiency will be lower. Also bear in mind a significant volume of water is needed in the system circulating to avoid short cycling.

 

hope that helps.

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@gavztheouch - yes got the 12kW. Bear in mind there is work and overheads involved for the MCS scheme in the installers side. In my case installation took quite a while so whilst the quote was similar, it ended up being good value in the end and especially since the RHI scheme pays back almost all of it.

 

System is quiet definitely. It doesn’t seem to meet it’s quoted numbers - looks like it will be about 20% more in the end. My concern with a 7kW unit would be hot water recovery time, that’s not a lot of power especially if you’re planning to use the (default) eco mode for DHW which is about 45% output.

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Posted (edited)
On 08/04/2021 at 08:01, J1mbo said:

@Dan F - the system is built around ebus. Vaillant do provide the vr920 Internet gateway option but there is no published API.

 

But, I would think carefully before going 3rd party controls. The system is designed o work with the vr700 which provides the flow curves based on outside, inside, and set point. Without this control the system will need to always be set to a higher flow temp to achieve an acceptable warm up period and hence the efficiency will be lower. Also bear in mind a significant volume of water is needed in the system circulating to avoid short cycling.

 

hope that helps.

 

I want to avoid interfacing with ASHP directly via ebus, but instead idea is to interface with Vaillant controller via modbus or something called eebus. 

 

Loxone will have all room/slab temperatures, weather data, as well as data on state of charge of Mixergy so should be able to coordinate everything, rather than relying on Vaillant ecosysten or more basic call for heat.

 

So wondered what others are doing.. are you using Vaillant thermostat(s) or third party call for heat to Vaillant controller?

Edited by Dan F

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