Having just confirmed a thermal fuse issue with my Nespresso Essenza Mini (as verified with a multimeter) I am now looking at repair. The machine is well out of warranty, one of those machines you rarely use but when you need it, it is there.
The machine overheated while descaling, it appears to be a fault in the user guide/design in which the fuse does not tolerate residual heat in the machine combined with recurrent use, and the user guide does not caution the user from rapidly descaling (like most machines, descaling takes a number of cycles).
I have taken a look, it is a UKLA EN4FM pump, the fuse is a Lebao branded 250V 104C G4A00 fuse. The 104 degrees seems to have a very low tolerance, I would expect the boiler to reach somewhere around 100 for the water, plus residual heat build up if repeatedly used in a short period.
The fuse is welded to the pump, I am a minimalist so do not believe in replacing the whole pump unit when only the fuse is blown.
Question for electronics people: Would say going to a 110 Celsius fuse create issues? This gives a little more tolerance on the machine when descaling.
by thegh0stwithin