@mike-h exactly as you describe. 

hope that helps!

@morh It seems odd that F1 and F2 are used for the HVACs, but F3 and F4 are used for the ASHPs, but thanks for confirming this. I will give it a go.

@mike-h apologies. Just wire it as the GitHub. F1 + 2. (I didn’t read your post properly…) 

@morh Thanks for the clarification. That's really helpful.

@mike-h 

As per the pictures from the documentation you wire F1 to A and F2 to B.

Its OK for there to be other wires in F1/F2 (They go to the external ASHP unit)

Yes V1 & V2 as per the diagram to provide 12V to the M5Stack

I found that a 120 ohm resistor between A&B on the M5Stack RS485 base was needed.

@minted_lamb Many thanks for that. I am waiting for my M5stack to arrive and in the meantime I have managed to install HA inside VirtualBox, thanks to a brilliant video by Smart Home Australia. EspHome and HA are very much uncharted territory for me. Thanks for the tip about the 120 ohm resistor.

@morh 

Thanks for your excellent work on this an reporting it on this forum. I was going to buy a Homely heat pump controller, but thought I'd start with this and get some more knowledge.

As you created a PR of the original work by lanwin, can you advise if your work was incorporated into the main build now take on by omerfaruk-aran at https://github.com/omerfaruk-aran/esphome_samsung_hvac_bus  

Before I fully commit to using it in production, I'd like to aim to be working with a maintained integration.

@minted_lamb news to me. 

I'll probably end up using the new project whenever I feel like updating.

@morh  I have followed the instructions on setting up the M5stack atom lite on https://github.com/omerfaruk-aran/esphome_samsung_hvac_bus/blob/main/readme.md

Linking .pioenvs/esphome-web-a07180/firmware.elf RAM: [== ] 18.6% (used 60856 bytes from 327680 bytes) Flash: [==========] 110.3% (used 2024497 bytes from 1835008 bytes) Error: The program size (2024497 bytes) is greater than maximum allowed (1835008 bytes) *** [checkprogsize] Explicit exit, status 1 ========================= [FAILED] Took 198.37 seconds ========================= ===== [ERROR] /config/esphome/esphome-web-a07180.yaml =====

@morh Apologies for the last post. It added the post before I had finished and I have since managed to reduce the program size by removing the lines related to the bluetooth facility.

Hi all, 

I have successfully running ESPHome with the heat pump and the code from @steven

Now I would like to write to the 0x40c4 address PWM, but cant figure it out how 

do you have any Tip for me? 

- platform: modbus_controller

    modbus_controller_id: ashp_modbus

    name: "Water Pump PWM"

    id: pump_pwm

    register_type: holding

    address: 0x40C4

    value_type: U_WORD

    lambda: "return x * 0.1; "

    write_lambda: "return x * 10.0; "

All this is far too complicated for most of us. Surely someone, if not Samsung, could sell a simple plug-in package.