The thermostat on my vendo 63 does not have any markings, either. I think clockwise = colder on my unit also. At about halfway on the thermostat the coldest soda's come out between 32-34 degrees.
And the 220-221 comment is epic from Mr. Mom.
![Smiley](http://soda-machines.com/discussions/Smileys/smc/smiley.gif)
I've never seen that movie, I don't think.