The MyVaillant App: a review

Friends, regular readers will know that I love my heat pump, a Vaillant Arotherm plus model with a nominal maximum heating power of 5 kW.

But regular readers will also know that I have been very disappointed with the software and controls for the heat pump. Back in October 2022 I wrote:

Vaillant Arotherm Plus Heat Pump: The good, the bad and the ugly.

In that article the “good” referred to the mechanical and electrical operation of the heat pump; the “bad” referred to the mysterious absence of a user manual; and the “ugly” referred to the Vaillant ‘sensoApp‘ used to control a few of the functions.

Recently Vaillant have released a new MyVaillant app to replace the sensoApp and I was eager to try out it. Could it be the elegant swan that grew up from the ugly duckling of the sensoApp.

In case you don’t have time to read this finely-crafted article, here is a summary of my findings: the MyVaillant app is a big improvement, but the operational data it provides is – as best I can tell – still just as inaccurate as it was previously.

Overview

After logging on initially I was mildly impressed, but then the next time I opened the app, I was asked me to log on again: select my country location, e-mail and password. This has happened several times since and I have been told over that Vaillant are working on this. I won’t mention it again, but it is a sign of poor testing.

After eventually logging on one is faced with a pleasing simple ‘Home Screen’. A glowing green circle displays the current set point temperature with the actual temperature below it – these numbers change in increments of 0.5 °C. The glowing circle changes colour from time to time, but I have no idea why!

Plus and minus buttons allow the set point to be easily adjusted. Clicking on these brings up a dialogue box which asks how long to change the set point for. After the chosen period – default is 3 hours – the set point will return to it’s previous setting or programmed value.

Click on image for a larger version. The Home Screen of the MyVaillant App.

The Home Screen contains buttons which link to four more important screens.

Click on image for a larger version. The Home Screen of the MyVaillant App and the screens to which it links directly.

These screens (see-above) allow access to the basic controls. It’s nice to see that ‘Activate Hot Water Boost’ – the most common reason I need the app – is just one touch away from the Home Screen.

Perhaps the most important screens are those for planning the weekly cycles for (a) heating and (b) domestic hot water. These are – in my opinion – textbook good design.

Click on image for a larger version. The screens for adding an  additional regular period of domestic hot water heating. Notice that one days settings can be copied and pasted onto another day.

So the app is well-structured, pleasant to look at and easy to use. A big improvement.

System Performance

Even bigger improvements have been made to the screens showing the system performance. An example screen is shown below for the week beginning 23 January 2023.

Click on image for a larger version. Example page show energy information for the heat pump during the week beginning 23 January 2023.The screen is shown left and on the right the screen is annotated to show how the various quantities relate to one another.

The display page shows:

• A: The electrical energy used to operate the heat pump – in this case 125.9 kWh
• B: The thermal energy captured from the air – in this case 230.1 kWh
• C: The thermal energy delivered to heat the house – in this case 332.1 kWh
• D: The thermal energy delivered to heat hot water – in this case 23.9 kWh

From these quantities the app calculates the Coefficient of Performance (COP) which it calls as Energy Efficiency.

If one touches any of the small graphs, a more detailed version is shown.

Click on image for a larger version. Clicking on the small energy graphs shows more detailed versions.

This display structure has been well thought through and is well executed. I would wish that the data could be downloaded, but this presentation is basically excellent.

However sadly the performance data shown is not accurate.

Accuracy

The MyVaillant app warns people that it is not accurate. But I think that despite this warning, in the absence of any other information, most people will take these figures at face value.

Click on image for a larger version. This warning screen appears before one sees the energy information pages. I recommend that one does not click the box asking not to show the message again. This should remind one that the data can be significantly in error.

Please note: Energy consumptions, energy yields and efficiencies are extrapolated based on various parameters. The actual figures may differ substantially in some cases.

Fortunately I have a monitoring system which measures the electrical consumption by the heat pump and the heat output of the heat pump. This allows a direct comparison between the app’s estimates and a measurement system which is certified to be suitable for billing.

So for the week illustrated in the figures above, the actual figures are shown in the table below.

Click on image for a larger version. Table showing the MyVaillant App estimates for electricity consumed and heat produced together with the measurements of these quantities by billing-grade instruments.

The MyVaillant estimates are seriously in error.

• The estimate of the electricity consumed is in error by 9.3%.
• The estimate of the heat produced is in error by 22%

Consequently, the estimate of the COP is seriously in error.

For the week in question, the average temperature was 4.0 °C and the minimum temperature was -5.1 °C, a cold week by London standards. A COP of 3.3 in such a week is quite respectable. A COP of 2.8 is not so great, and might lead someone to search for system improvements which would be illusory.

Click on image for a larger version. Temperatures in my back garden during the week in question.

The real problem with these errors is that the erroneous estimates are completely plausible.

Summary 

Assuming that Vaillant sort out the problem logging on to their app, then this app represents a really significant improvement over their previous offering. To all the engineers who have worked on this I would like to say: Thank you.

But the inaccuracy of the reported quantities is significant and I feel that if Vaillant cannot improve these estimates, then they should be indelibly marked as ‘indicative’.

Signal Generator

Who wouldn't want to turn their iPhone into a Signal Generator for 69p?

Signal Generator is an app I have actually used more than once!

• In the lab we were testing an acoustic thermometer (as you do) and we wanted to test the effect of white noise. I realised that Signal Generator was on my iPhone and in a trice our problem was solved.
• In the last couple of talks I have given about acoustic thermometry, I have been able to allow people to experience 7.5 kHz  – thanks to this little app

So if your line of business involves acoustic thermometry, or acoustics, or music, or you just want to know low the upper limit of your hearing has fallen, this is a great little app. It does use up a lot of power, but that is about the only bad thing I can think to say it about it.,

• Frequencies can be entered on a key pad or on a dial
• Frequency range is from 1 Hz to 20 kHz with 1 Hz resolution
• Musical tones can be selected
• Sine wave, square wave or triangular waves are possible, as are ‘white’ and ‘pink’ noise.
• One channel or two can be selected

So if you want an audio signal generator in your pocket: this is the app for you.

Have a nice weekend.

The Elements versus The Periodic Table

Two iPhone Apps. Theodore Gray's 'The Elements' (left) or Merck's PSE-HD (right). Both apps are shown displaying basic information for Technetium.

Did I mention I had a new iPhone? Well obviously the first kind of app I downloaded was a periodic table of the elements – it just gave me a comfortable feeling knowing that I had that information close at hand. And what could be better than a Periodic Table app? Well, obviously two Periodic Table apps! And so here I compare the free Merck(TM) PSE HD app with the £6.99 app called ‘The Elements’.

'The Elements' page for Technetium. Touching the image allows you to rotate it and the text scrolls for an engaging description of the element.

The Elements is an app written with love by Theodore Gray, co-founder of Wolfram Research who make Mathematica. It is a simple app to understand and navigate. It has an introductory essay, a picture of the periodic table with animated pictures of each element, and splendid animation of the ‘The Elements’ Song by Tom Lehrer. Tapping on an element brings up a screen with a rotatable picture of the element, and an engagingly written essay by the author. I did find a tiny error on the page about Helium, but Theodore said he would fix that in the next release. Each essay links the physical properties and the history of the element and has links to the pages for other relevant elements (this makes it easy to browse and ‘get to know’ the elements).

The main attraction of this app is its accessibility – it is simple to use and a pleasure to interact with – one of those apps you will show your friends to make them think that your insanely expensive mobile phone might not have been a complete waste of money. On the down side, it is a bit limited and expensive as apps go. It does have links to Wolfram Alpha’s database on the elements, which is nice, but then you are back to browsing web pages.

Link to UK App Store

The Merck PSE (HD) has more data built-in to the app than The Elements, and it has many different ways to display and interact with the data. The main screen is a picture of the periodic table, and touching an element brings up a panel with basic information. Touching the panel causes it to flip and on its reverse are different categories of information shown in considerable detail, from the history and discovery of the element, to technical data. At this point the app is just ‘really useful’. But there is more: touching the Merck ‘M’ on the home screen brings up a new way of viewing the data where one can view how a property varies across the periodic table.

Turning the control increases the temperature, and the periodic table graphically shows which elements are solid, liquid, and gas at that temperature.

For example, selecting ‘state at room temperature’ allows one to view the periodic table colour-coded as to the state (solid, liquid or gas) of the elements. A rotary control allows one to change the temperature and see visually which parts of the table melt and then vaporise in which temperature range: it is delightful. Similarly, selecting electronegativity shows how this property varies across the periodic table. Not sure what electronegativity is? Then select the glossary tab to find out.

The periodic table graphic shows how the electronegativity of a substance varies with position in the table.

My favourite is the discovery tab which allows you to scroll back through time and see when each element was discovered – and the app displays an image of the discoverer. And there is lots more too.

The faces of the people who discovered each element.

This app is data rich and carefully thought out. Having it on your phone gives you that comfortable feeling, knowing that even when your network connection is down, you will still have access to melting point data for the elements

Link to UK Apple App Store and  Android marketplace

Which is best? For people who enjoy tech lore, or if you’re studying Physics or Chemistry, then the Merck PSE app – for free – is a must have . For people who have £6.99 to spare – and are perhaps curious about science – but not professionally involved, ‘The Elements’ is a real pleasure to own.

Spectrum View

A spectrogram or sonogram. It shows the frequencies present in a sound. In this graph a flute is playing a rising and a falling scale over a single octave. Click for larger image

Spectrum View: Wow! How can this app exist on a phone? The app digitizes sound from the microphone, computes the frequency spectrum about 100 times a second, and displays a graph showing how the spectrum changes with time. This particular app is free, which means I shouldn’t complain. And I’m not. But since the app doesn’t provide any way to export the data, it is really nothing more than a fascinating toy. But I think it is fascinating enough to earn a place in my ‘Science’ folder. While looking around I notice that there are several semi-professional apps that will export spectra, and function as oscilloscopes as well. I will review them when I pluck up the courage to blow £15 on an app!

A constant note (F) on a flute.

Atom in a box

Visualisation of the 4 p orbital in hydrogen.

Did I mention I had a new iPhone? Well the other day I found out that one my favourite pieces of software was available now as an app: Atom in a Box. The app is simple – it shows the shapes of the electron orbitals in a hydrogen atom. And that’s all!

What I love about it is that it works at multiple levels. To a student learning about physics they can appreciate that these are just the shapes of the orbitals. They can look at the orbitals from all angles and see the shapes of the lobes. When I was a student I had to try to imagine what these things looked like!

But if they want to delve a bit deeper,  application shows the mathematical function that generates the orbitals. And so if you are interested you can make connections between the physical form of the function and its mathematical representation. It also uses colour cycling to show the phase of the wave function, an especially difficult-to-describe aspect of complex functions.

So if only to remind yourself of what these wave functions look like, IMHO this is worth 69p of anybody’s money. (App Store Link)

TOP TIP: To take a picture of the screen hold down the HOME and the SLEEP buttons at the same time. An image of the screen will appear in your camera roll.