Homebrew Weishaupt control based on Tado

jan2642 · October 2022

Hi,

We have a Weishaupt WTC-32 which uses eBUS but is unfortunately not supported by Tado. There are smart TRVs on all the radiators and I programmed the Weishaupt thermostat in the living room to provide heat whenever one of the TRV's was scheduled to heat a room. While this seemed to work fine I've noticed that when the TRV's in the living room are closed, the WTC regularly starts burning in a futile attempt to heat the living room.

This had to be fixed ! First step was to get an eye on the eBUS between the WTC and its thermostat. I've built an eBUS adapter and used ebusd and reverse engineered message definitions available on GitHub: https://github.com/john30/ebusd and https://github.com/J0EK3R/ebusd-configuration-weishaupt Works great!

The WTC can support multiple thermostats. It will provide heat according to the one with the highest needs. With ebusd and the message definitions I can act as an additional thermostat. There's really only one parameter to send: the temperature of the water going to the radiators. The original thermostat has been set to 'summer mode' but it still handles the hot tapwater.

The Tado state is fetched from the internet via the unofficial API. From this I get the current_temperature, the wanted_temperature and the heating_power for each room. A very simple formula is used to derive the temperature of the radiator water, a linear mapping of the highest heating_power to 30-55 degC.

T = (max(heating_power) / (55 - 30)) + 30

So far it works fine without taking the wanted_temperature or outside temperature into account:

Any suggestions to improve this simple (naive) scheme are greatly appreciated !

Bilckie · May 2023

Despite what's in the Tado documentation, it does work well with a Weishaupt system. I have it installed. Let me know if you need details

alexsporn · July 2023

Can you provide more information on how to get it to work with Weishaupt?

ERHU · October 2023

I also have a Weishaupt WTC-32 and I 'am also very interested in more information about your solution

nz75c2 · November 2023

I am also interested :-)

bio · December 2023

@Bilckie I'm also very interested in how to set up my Weishaupt WEM [2-wire] with a tado wired smart thermostat. It is supposed to control a WWB (former WWP) heat pump. Since I could't find any OEM wireless thermostats or temperature sensors, tado would fit perfectly.

Bilckie · December 2023

Looks like I missed quite a few updates since I logged mine. Apologies to everyone. I don't seem to receive notifications.

I was able to get Tado to work with my Weishaupt system (both the older WTC 25 A, and the newer WTC C-PEA 25 B) by connecting the Tado controllers NO and COM connections to the H1 connection on the Weishaupt. And then change the menu setting P15 from 1 to 0.