I recently picked up a really nice U-Line under-cabinet fridge for my kegerator. It nicely holds 2 kornys, and has room in the back shelf for yeast samples and my CO2. Perfect setup! My next step is to round it out with a tap tower. The last thing I want to go is go nuts with the hole saw and ruin this fridge, by running right through a refrigerant line.
On this model, the back interior wall of the fridge has a chiller plate, with the defrost drip tray at the bottom. What I don't know is, if there are additional lines running in the top of the unit, or if that is just all insulation, and I'd be safe to drill away. I have been trying to track down a schematic to help positively identify the layout, but to no avail.
Has anyone worked with these units before? Is there a way I can locate the lines if they exist? I've read some things about using some sort of corn starch mixture to help identify lines, but I don't know how reliable or applicable such a method would be for my fridge.
Here's a few pictures of the unit: