The purpose of the differential thermostat is to monitor the temperatures of the solar panel and the water boiler and when the temperature is higher on the panel than the boiler, it turns on a pump that moves that heat to the boiler.

The controller already has its basic operation implemented but it lacks some of the more advanced features like overheating protection, frost protection, minimum temperature check, and so on.

I hope that together we can finish the project code along with its custom PCB so that the design can serve anyone that wants to make a controller for themselves.

More details can be found on the video explaining the project
https://youtu.be/GMF6dyCDUPo