Hello,
I used FHEM on a Raspberry Pi to readout my Waterkotte Resümat CD4 via this https://wiki.fhem.de/wiki/Waterkotte_heat_pump_with_Resümat_CD4
Having Home Assistant in use, I tried to integrate it via Node-Red:
Following palette needs to be installed: node-red-contrib-home-assistant-websocket
node-red-contrib-buffer-parser
node-red-node-serialport
node-red-show-value
The heatpump is connected via USB-Serial-Port Converter
The flow reads out the Resümat every minute. Set Command are working for Heating onoff/warmwater onoff/temperature heating/temperature warmwater.
Use at your own risk!