This is a fork of @Kasper-73's repository, all credit to him for doing the hard work. (Original: https://github.com/kasper-73/CTC-GSi-8---Homeassistant)
I updated his script with a couple of small fixes, and adapted it to run on an ESP-12F_Relay_X2 board. This adds the option to utilize the EcoHeat Smart A and Smart B inputs, that enable a lot of power saving featurs. I only wonder why CTC hides these features so well.....
For connection between CTC EcoHeat and Homeassistant (testet with CTC EcoHeat 412). I haven't found all the modbus registers yet from the lists in the pdf files
I added a Dallas temperature sensor as well, connected to GPIO2
RJ12 cable cut in half an connected to ESP-12F
Pinout for the RJ12 cable connected to the display of the CTC heat pump
1: GND
2: 5V
3: Not used
4: RX GPIO 13
5: Flow control pin GPIO 12
6: TX GPIO 14
Using Esphome it is possible to read and write modbus.