Our newly installed heat pump is a WEIDER SW210. It has an RS232 interface for PC/Modem connection and a more-or-less documented protocol.
I created a simple component for ESPHome to read the various sensors into Home Assistant. Currently, it works in automatic mode only and is limited to reading the current sensor states.
The component, along with a short documentation, can be found here: GitHub - andyboeh/esphome-weider_wp: ESPHome component for Weider Heat Pump (RS232)
Although interest seems low, I’ve invested a bit more time into the integration and there will be a bunch of new features in the upcoming weeks (reading and setting codes, getting error messages, clearing errors = reset …). A bit more details in order to get started:
The controller, the WT08, has a RS232 interface. In order to talk to it with an ESP32, you need a level shifter like a MAX232 (I used an SP3232). Make sure to get the cabling right, i.e. a crossover cable with the data flow pins connected properly. Weider’s protocol description contains a schematic.
The basic idea is that the ESP32 talks directly over this serial connection with the heat pump. This eliminates the need for the WeiGrid box, which is a UART-to-ModBus TCP bridge, based on a Raspberry PI (judging from the picture I’ve seen in other forums).
Once you have the component installed on the ESP32, it will automatically start parsing the messages received from the UART and you will get a bunch of sensors with the details of the heat pump.
Please be aware that this was tested with my heat pump only and I have no idea if there are any differences in the communication protocol in different firmware versions.