Rinnai sell a wide range of stuff - heatpumps, central heating, fires, AC units, etc.
I’ve recently purchased a fire, and the optional wifi module. I’ve been able to understand a lot of how the wifi module connects to the iOS/Android app, how the wifi module connects to the cloud (AWS, via MQTTs) and get the fire to turn on/set the temperature/turn off etc.
The protocol for local communication from something on the same network segment is pretty straightforward (TCP port 3000, you send it the right string and the fire does what you ask it to) but I haven’t quite worked out the entire comma delimited command structure.
Wifi module: Gas fireplace Wi-Fi module (R7000)
Has anyone seen a plugin, or come across the same challenge?