I have finally gotten back to this project and created a working sketch that communicates with my Vera controller. I have this set up as a 3 button on/off (6 switches on the board) and have that working successfully with Vera. I also have my Vera sending temperature data back to the OLED display. It alternates between the outside temp and room temp for my master bedroom where the switch is located. I have posted the Arduino sketch under source code here.
Hi you should provide your heatpump info to Toni at the below link. check manufacturer + model + relevant data from your remote control and also your protocol info. then other persons using your heatpump can benefit from your work
PS. I am for my heatpump not using arduino/mysensors, as it was actually much easier to use/integrate Wemos D1 Pro mini + ESPEASy + P_115 heatpumpir into my Domoticz.