A tick is missing

Positives:
- Has a nice rotating wheel which allows you to control the temperature well.
- Display is easy to read and is illuminated background
- Assembly easy
- Various settings
- Operating

Negative
- Regulates the temperature is too high. The controlled temp. Is always 1.5 to two degrees above the measured (direct from sensor). That you can not resolve with the correction also. So I want that to 21 degrees is regulated, then I make a better 20 degrees.
Update the firmware of the CCU2 out, is only possible with tricks. Here is a decent upgrade strategy would be useful. Or perhaps a test department, the time the SW tests that you released!