Hi @BartGijsbers , I've built a board based on a ESP32 just like you to get started :-) I wanted to double check the pinout on the Ecodan, do you happen to have the color/pinout mapping? My cable has the following cables: red/brown/orange/yellow/green. I've read somewhere that pin1 is 12V?
Also, I'll fork your code on Github to make some changes. I'm using platform.io and it's quite picky regarding C-style forward declarations (whereas the arduino studio works around that in the background).
We found some more details relating to the ForceDHW and the use of set command 0x34 (byte0). Think you have to set byte1 to 0x01 (flag?) and then byte3 : 1=Force or 0=Normal.
I found this too, bytes 1 and 3 set, I couldn't turn it off though. I also tried byte 1 to 0x01, and tried setting byte 4,5,6,7,8,9... etc in sequence, but didn't seem to find anything
I've adapted the code for Elegoo Mega 2560 R3 with Ethernet Shield to control MSZ-AP25VG-E1 (I assume the unit is compatible).
The IP/MQTT side works properly but I don't see communication with the pump.
I assume that the code uses UART1; or do I've to set something to select the serial port?