Sauna

Hello 👋

We inherited an old sauna from the previous owner of our house and it has the pictured control panel. The left dial I get and the right side of the right dial is runtime, but I've never figured out what the left side does. It doesn't seem to power the oven while running, so I thought it might be a delay timer, but after running out it just stops.

The stickers say "time preset" and "runtime". I don't know what time preset could be.

The model says "Type 10210" if that helps. Google didn't.

Does someone have a similar model or maybe even a manual? Or just a general idea what the timer could be?

Thanks!