16kW Altherma ERLQ016CAW1 Low Temp connected

[ezfrag2021]

What a wonderful project. Thank you so much for all your hardwork getting this working so nicely with ESPHome! I used an ESP32-WROOM-32U Devkit with the external antenna and routed it to the outside of the Altherma casing to avoid the Faraday cage effect. Only issue I had was that the 5V pin from the Altherma wouldn't provide enough power for the ESP32 WiFi so had to use external USB power.

I would love to be able to change my DHW setpoint in Home Assistant so that I can properly integrate the heating and hot water into my solar system. At the moment when I have too much solar energy I dump it into the car battery but it would be nice to be able to put it into the DHW tank. I have not seen anyone able to write a DHW set point number back to the Altherma but it's something that would be really useful. Thanks again!

[jjohnsen]

Nice to see you have it running @ezfrag2021, and thanks for sharing the details about the ESP32-WROOM-32U and external antenna. That is useful input.

When it comes to controlling the heat pump over the X10A interface, it still looks like changing values such as the DHW setpoint is not possible directly, at least not without using other digital inputs on the pump.

Some Altherma units have a Smart Grid input, which may allow modes like “Forced On”. There is some discussion around that here:
raomin/ESPAltherma#170

In the "Forced ON" operation mode, the heat pump system makes use of solar/grid power (when it is available, as measured by the solar inverter/energy management system) to produce domestic hot water and/or heat up or cool down the space

I am looking into this myself as well, but mainly for limiting usage rather than increasing it. @alexdelli is also exploring something similar here: #24

And this config may also be relevant: https://github.com/alexdelli/esphome-altherma-ERLQ011CAV3/blob/main/esphome-web-965350.yaml

There is also Arnold’s P1P2 project, which support setting values: https://github.com/Arnold-n/P1P2MQTT

But that requires dedicated P1P2 hardware, so it is a different approach than this project. For the ESPHome/X10A setup, I still do not think we currently have a way to write the DHW setpoint back to the unit.