Boiler dying

Use caution - assuming yours is the same as my design, your (very) minimal description may mean that your heating element is corroded through to the water in the boiler, and still functioning only by completing the circuit through your machine's ground wire. Low power results because you're getting a high-resistance return path, only "connecting" to the remaining portion of the heating element, and going through fresh water, which isn't that good of a conductor. The machine's metal case becomes the return path for the heating power, and the thermostat becomes irrelevant in this situation - the only thing preventing a meltdown is a cheesy little snap-disc temp cutout.

If you're comfortable with some live electrical work, the quickest (NOTE: momentarily hazardous!) test for this would be to use a three-to-two-wire "grounding adapter" on your plug, so you'd deliberately be taking OUT that ground path. The idea is to remove the ground ONLY momentarily, then use a test-light or voltmeter to check between any shiny metal part of the case and a good ground, like your water pipe or faucet. If that test-light glows, the element has indeed burned through.

Replacement ain't easy - and the original part is not sold to consumers, so you'd have to send the machine in for repairs - very expensive, to the point where it's not likely to be worthwhile, I expect. See related post on using a Saeco element to replace it if you're game.

Is this a crappy design? YES. Crappy at least in the sense that it's dangerous. But hey, it looks cool, and that's the important thing.