Hello, I don't own an Anova, but I have made my own immersion circulator. If I may advise you, do NOT try to bypass the fuse with aluminum foil as it doesn't handle the high amperage the heating element uses and may burst in flames.
You can test the unit safe and easy using a cheap portable multimeter (If you live in the US, I bet you can get an inexpensive one in almost any hardware store). Just configure it to measure resistance (the guy that sells you the multimeter will show you how if you ask) and test both contacts of the fuse. It shall show you almost no resistance, meaning it's ok. Then test the heating element the same way. It shall be low, only a couple hundred ohms at most. If any of these is burnt it will show very large or infinite resistance.
If both are ok, it can be almost any other part, from the circuitry to the heat sensors, but most the third most probable suspect would be the triac (the 3 leged chip with black heatsink). I can't help more cause here where I live these are too expensive for what they do....
Hope this helps you.