@horseflesh
The temperature for simmering and for boiling water will depend on your elevation.
For simmering, 90C (194F) to 95C (203F) is usually the right range, depending on what you're trying to simmer (since simmer is not exactly a precise word).
For boiling at sea level, I'd probably use 105C (221F) if you're looking for a roiling boil, and closer to 100C (212F) if you're just wanting a bit of a boil.
The thing that complicates these things is altitude. For a lot of people, living at higher urban altitudes, water boils closer to 95C (203F). So that reduces the delta between what a simmer is and what boiling is.
There should be quite a few sites on the Internet that can tell you what temperature water should boil at for your altitude. Here's the first Google result I found:
https://www.engineeringtoolbox.com/boiling-points-water-altitude-d_1344.html
As always, for any given temperature setpoint, the Control Freak will basically transition from pushing lots of heat to raise the temperature mode to pushing a little heat to maintain temperature mode. So if you want to actively boil water, you want the temperature setting to be a little higher than the boiling temperature. I just wouldn't go too much higher, or you might find yourself dumping a whole lot of extra energy into that water.
Edit: I just saw @Smithy's post, so you're probably already on top of the altitude thing.
