
Hans Testus
App doesn't support switch of language, always takes the device language with no option to configure. standard nowadays is that you can set this within the app settings of the Android system. Also missing: option to manually start heating, just like I can manually start hot water. At this time of the year, one doesn't need the heating all day, but sometimes just want to turn on the heating. Doesn't sound like an unusual request. But it's not possible, I have to change time plans...

Drew Mills
The controller unit has a very poor antenna which does not work on my main house Wi-Fi connection even though several other devices nearby work well. It is not possible to change settings when the device is offline and then take effect when the device comes online next time. There is no option to turn the hot water on for 10 minutes with a single press. Designed by engineers without sufficient consultation with real world users. Fiddly HCI.
1 person found this review helpful
Viessmann IT Service GmbH
April 10, 2026
Hello Drew Mills. We apologize for the inconvenience. Please send a description of the issue, screenshots/photos, and the communication module’s serial number to customer-contact+DrewMills1004@viessmann-climatesolutions.com. This will help us assess the situation thoroughly and provide an appropriate resolution.

Keith Naylor
You need this app to control your heating and hot water. The problem is that it is limiting your daily schedules to 3 phases. For example to prevent your heating running all night set the Reduced setting to a desired lowest temp. Next is Normal for in the daytime and there is comfort for the cold evenings. However it is not very flexible. So you can't do Reduced, Normal, Reduced ( because you might not want to heat your house in the day). It needs to be more flexible.
1 person found this review helpful