Pretty straight forward to access. You'll need to find a good surface to place the device sideways without damaging the levers (or the thermometer).

The use of a piece of foam, or ugly pillow might be handy.

Use a regular Phillips (+) screwdriver to remove the six screws at the bottom of the device. Note that the one in the centre front is shorter than the others. Make sure it goes back in the right spot!

Remove the bottom plate. You'll find a PCB and some cabling, that's it. Go to the last step for some hints about the PCB.