Viesmann DHW Control - Set Temperature in ECO mode
I have Viessmann Vitodens 100-W B1kF connected via OpenTherm to a Wireless Receiver (EU) version. There seems to be a problem with DHW and I would like to share my experience after investigating and talking to Tado about it.
I hope this suggestion will help others so that maybe Tado implements it.
Viessmann has 2 DHW modes: Comfort and ECO.
- In Comfort, you set a temperature and the Combi Boiler tries to have it more easily ready for you. This is the part you can control from Tado at the moment (set a schedule and all) with a value from 30 to 60 degrees Celsius. Mind you this option consumes more energy (especially gas); In my experience 0.2-0.5m3 per day more than ECO.
- In ECO you should be able to set a DHW temperature to your liking and the boiler will only heat the water on demand.
The problem with Tado and Viessmann on OpenTherm is that you cannot set ECO DHW.
In theory from the app, setting DHW to OFF should enable ECO on the boiler, and you set the desired DHW temp from the boiler. There is a bug or a miscommunication between them.
So what happens? Setting OFF in Tado, makes the boiler go to forced comfort and the DHW temp to 55 degrees Celsius. Which you can imagine is a huge wasted of energy.
Now, I have 10 emails exchanged with Tado about this, and the summary is that they know this is an issue, and they are in contact with Visemann about it, BUT, they can't give an ETA or if this issue will ever be addressed.
In my opinion, this is a big issue and would love to see it fixed, as it's so far the only bad experience in my Tado setup.
Has anyone had this issue with OpenTherm and the Wireless receiver, maybe Viessmann or another boiler?