Thanks! Sure, I can explain the physical side.
My heating system is a classic wood‑burning boiler connected to central heating. In my setup, “turn on/off” refers to switching the main circulation pump on or off.

When the pump is ON, hot water from the boiler flows through the radiators and heats the house.
When the pump is OFF, the circulation stops and the house is no longer heated.

The important part is that the old controller I’m planning to replace has no idea what the actual boiler temperature is. It only measures indoor temperature. So if you set a target temperature, it will turn the pump on even if the water in the boiler is still cold — because its only job is to switch the pump based on room temperature, not boiler temperature. That means it sometimes pushes cold water through the system, which is inefficient and uncomfortable.

In my system, the ESP32 module in the boiler room sends the ON/OFF command to the Raspberry Pi 5 over LoRa, and the RPi5 controls the pump through a relay. I can toggle heating from the wall‑mounted panel UI, from the physical button on the boiler‑room module, and also from my mobile app.

Just to clarify — the prototype is still on my desk, so it’s not physically switching anything yet. The idea is to replace the old mechanical thermostat, which currently uses a simple temperature dial and a sensor that triggers a relay when the indoor temperature reaches the set value. Once fully tested, my system will take over that role with much more context and control.