Ciao Sergio,
If you only wich to control your boiler, then you can use the EU version of the HestiaPi.
The trick is NOT to solder the transformer on the PCB.
To power the HestiaPi, use a mobile phone power supply and connect it to the micro usb port of the Raspberry Pi. This should also work on the “data” micro usb port of the Raspberry.
Then connect the 2 wires of the boiler to the blocks as described in the thread below:
Hope this helps.
Regards.