Mill panel heaters wifi

I had a brief conversation with Mill via mail about 3. party integration, and they’re currently working on getting IFTTT up and running. I would hope that means local control?

How is this integration ment to be used? When setting the temperature with HA the programs in the app no longer work. Setting the temperature in HA seems very unreliable, for example my HA thermostat is always saying target temperature 23C - regardless what I set it to. If I change it the heater reflects this change but the target temperature in HA goes back to 23 soon after, preventing me from actually setting it back to 23C without calling the service manually.

The thermostat component shows “heating” constantly even when it’s not.

Also, curious why my heater has a “fan mode” displayed? It’s the AB-H1500WIFI so obviously no fan, but it does have 3 power modes that I can’t control from HA.

After some time I got access to the API that MILL made. But this is only for controlling their devices through their servers.
The same will be with all other intergrations. Going through their servers.

So since I did not want to be depending on internet and that their servers were working I opened the heater and started looking.

I found a chip that could be programmed, but having been down that road before without any success I chose not to do that.

I checked a bit more and found some headers that gave me 3.3VDC and one pin that I could control the relay.

So a small esp-01, changing the temperature sensors (since I don’t have a ADC on the esp-01) and some wires (no soldering). I now have full control over my heater. And if it breaks, I can just connect everything back and still have full waranty.

And with my knowledge it won’t be able to cause any more risk that the oven can start a fire. (There were no internal control in the chip telling the oven to turn off)
I also added in the firmware that if room temperature is hotter than 28degrees celcius it would turn off.

I would like to see if this works as well.
I have a Telenor 4G as WAN failover. Whenever the network switches to the 4G, Mill (even with the app) stops to work. I guess Telenor blocked some proxy/websocket that are used by Mill.

If you do what I did you have full control and can implement how you want with Home Assistant. No need to go online.

Do you have a sketch or code to share? Thanks

Will try to make something during the weekend. But it might depend on the model. I will post what I have.

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I have created a guide on how I did it. Hope it can help. And please give feedback on improvements.


Is there a way to use the Mill component with another sensor? I have the heater below a window and it reports lower temperature than what’s in the rest of the room.