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Hello,

After lots of deliberating, multiple quotes and heat loss surveys, and a canceled Octopus install, we are about to have a Vaillant aroTHERM Plus 7kW installed next week by an independent heating engineer. He is HeatGeek Assured and is using the VitoEnergy platform / MCS Umbrella. So I am excited and optimistic that it is going to go well!

I am going to ask my electrician to install an Eastron SDM120 electricity meter, that I already own, in the feed from the consumer unit to the heat pump. So I can track energy consumption.

If I wanted to participate on HeatPumpMonitor, do I need to buy a heat meter?
Can I get data out of the aroTHERM via ebus instead? Is that significantly less accurate?

I am interested to see how it performs but maybe not spend lots of time optimising it.

Thanks,

nick.

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Hi Nicholas! You can get all relevant data via ebus, however the temperature sensors on Vaillant units can be problematic, which can lead to significant errors. See the thread here:

Electricity metering on the Vaillant units is highly accurate, so this only impacts heat measurements. I also have an arotherm 10 kW unit and am running a “hybrid” monitoring where I combine ebus measurements with my own temperature readings.

Depending on your technical skill level and - maybe more importantly - willingness to invest time, an independent heat meter would be the best option.

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Exciting times! Hope the install goes well.

Make sure it’s a modbus version if you want to be able to read data from it.

If you think you might want a heat meter installed, it’s much easier to get it in when the system is first being installed:

We offer a pre-provisioned monitoring bundle including a heat and electricity meter:

Or you can just get a heat meter on its own, or source one yourself from elsewhere. But make sure it’s got MBUS if you want to be able to read from it:

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Thank you very much for your advice.

Annoyingly the “Axioma Qalcosonic E4 Heating & Cooling Meter M-BUS DN20 QP2.5” isn’t currently in-stock. So I ordered the “Sontex Superstatic 789 Heat Meter M-BUS QP2.5” instead, which was a bit more expensive.

Exciting to see it all come together this week.

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I meant to report back on how I got on. My heat pump install completed on the 11th October and then I got emonCMS monitoring of it up and running on the 12th November.

This is what my monitoring system looks like:

IMG_1851
IMG_1851916×828 156 KB

I have completed the following tasks to get it up and running:

  • Install emonSD on a Raspberry Pi 3B+
  • I don’t have a convenient power socket nearby, so it is powered using PoE
  • I ran a RS-485 cable from the SDM120 near my consumer unit, to the Raspberry Pi, which is next to the heat meter
  • it took me a while to work out the emonhub.conf configuration to use but I got there in the end
  • I couldn’t work out why syncing to emoncms.org wasn’t working - I then tried doing a Full System Upgrade and that made it work.

Next steps:

  • Setup some kind of outdoor temperature sensor
  • Sense when the hot water diverter value is active
  • Look at getting data out of Vaillant via eBUS
  • Look at getting data out of Mixergy Hot Water Cylinder

Here is the page for my system on HeatpumpMonitor: System 552

I am not totally happy with the performance of my system - I would like to be track for a SCoP of over 4.0… hopefully I can find some optimisations.

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Feeling frustrated by my lack of outdoor temperature sensor, I decided to look into using weather data instead. I am aware of @glyn.hudson’s metoffice-emoncms.

However I don’t believe you can get historical data from the UK MetOffice API. I found that you can get temperature data from Open-Meteo back to 1940! And you can even export the data as CSV and timeformat=unixtime - making it very easy to import into the EmonCMS console.

I also wrote a quick Ruby script to import the current temperature, humidity and wind speed every hour:
https://gist.github.com/njh/6dbb129504ec881d47f2cf278fe9f42a

So now I have several years of Outdoor Temperature data in a feed. And I can use more of the heatpumpmonitor functionality :slight_smile:

I still plan to get an outdoor temperature sensor setup again…

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Nice work! :clap: