Hi Laitch, ok, i've worked on it today.
I boiled it with your relation water-vinegar, and then i put it into the ultrasonic, cleaner, nothing.....
I've prepaired a bowl with ices and water, and othe boiling one, and i've donne some cycles...it continue without closing, so i assume i need a new one.
Another good simple intervention today was the waning switch. It has been stiff from the beginning ( 8 years ago, bought used).
i unsoldered, and dismantle it, i put it in the ultrasonic box with 100% vinegar, and after that it clicks easily and smooth.
I quasy lost a spring that can fly to mars in the dismantle process..
I've empty the oil, and retired the filter, waiting now for parts...