Same issue here. HA receives data from Ethernet Gateway for only a few minutes and then:
DEBUG (MainThread) [mysensors.gateway_tcp] Connection lost with <_SelectorSocketTransport closing fd=42 read=idle write=<idle, bufsize=0>>
I also have MYSController connected to the GW and it remains connected. There is an open issue as others are also having the same problem. Am wondering if anyone here is having success with Ethernet Gateway connected to HA.
Figured it out. I had to send HVAC_FLOW_STATE to HA, in order for it to figure out that it was a "thermostat". Only problem is that it shows up with states "Auto" "Cool" "Heat" and "Off" in the dashboard, even though I only have the possibility to heat, or turn it off.
@Multimax do you send initial states for all children for this multi relay node? HA won't show anything that hasn't sent initial data to show.
https://www.home-assistant.io/integrations/mysensors/#presentation
