Unfortunately, local link mode is completely useless on these devices 
It is possible to make a local connection only when the thermostat is in access point mode. It opens up for approximately 30 seconds after powerup; the thermostat represents itself as an open “Smart Thermostat” wifi network. Yes, anyone can connect. Yes, even if fully configured. After the timeout the thermostat switches to client mode and shuts off local port.
Consequences:
- It is possible to connect only within 30 seconds after powerup
- If connection is lost, reconnecting is possible only after powercycle.
- Your control host has to be a wifi client and thermostat is an access point
- Situation with multiple thermostats is unclear because you would end up in multiple wifi networks with the same SSID.
Conclusion:
Totally unusable, Devi forces you to use their cloud even you’re standing next to your door.
To tell the truth, i decided to stick to Devi installation only because:
- The only potential alternative on the local market could be Electrolux ETS 16; but i don’t know if they impose the same restrictions or not
- I have already invested a lot of my time into reversing Devismart and got usable results
Thanks Danfoss, we know you care!