Delonghi Primadonna s 26.455

Hello everyone, I have a mega problem with my Delonghi Primadonna 26,455. it always sengnala me empty circuit, I have changed all solenoid valves, water pump, tubes, water meter and diaphragm and also the power board but still not solved the problem. When I turn on the steam, the pump starts and gets quieter and quieter and keeps telling me "fill water circuit ". It does the rinse and coffee but I can't make a cappuccino or even descale.
I hope someone can help me find the problem

If the pump becomes quiet, you have a blockage. In a water pipe, or in the steam heating, coupling for the milk carafe. You have to look for the blockage piece by piece.

I blew inside the small tubes and they are free. The solenoid valves are new. Could it be the heat sensor placed in the U-boiler?

I changed the thermostats in the steam boiler and the temperature gauge placed in the boiler and still like before :angry:when I attack the steam it short-circuits and disconnects the circuit breaker

Unfortunately, it is a lousy coffee machine and impossible to repair. It still reports empty circuit to me. I literally changed everything