The video (not mine!) explains the settings of a similar system I am using. For more info, go to http://openenergymonitor.org/emon/
Other sites where I publish live data: http://daturach.github.io/
Uses a D1 Mini and Arduino code with an HTU21D for ambient sensing and two DS18B20 OneWire sensors for inlet and outlet temperature measurement. The derivative of the temperature difference across the heat pump detects the heat pump mode.