How do I shut off power to the pump timer?

[roxyrhoads]

Hi everyone-
I've been having issues with my pump timer not working. The cogs in the "visual motor check" window are moving. I've already tried changing the trippers and that didn't help. So I bought a new timer motor. I've read instructions on how to change it and the very first thing is to always shut off the power (duh). I opened the small box next to the timer box, but it didn't look like a normal breaker like I was expecting. It says "clutter control" along with the nice "DANGER HIGH VOLTAGE" warning.
I'm guessing I just turn the knob to "0", but obviously I want to make sure. I'm including a pic, so hopefully that will help. Thanks!

 

[roxyrhoads]

Here's a closer look at the actual box I'm referring to.....

 

[JohnT]

I expect that box is something like freeze protection. You'll need to look at your panel or a subpanel for the breaker for your pump.