How do I access the hidden menu to view all parameters?

First enter programming mode by pressing SET and the up arrow key together for 3 seconds until the °C or °F LED blinks. Then release the keys and immediately press SET and the up arrow key again for more than 7 seconds until the 'L2' label is displayed, followed by the 'Hy' parameter. From there you can browse, view, and change any parameter using the arrow keys and SET button. (Page 1-2)