I've been looking through the forums and am having a hard time finding what I need. I'd like to wire an ITC-1000 into a refrigerator thermostat and still be able to keep the freezer on top functional. Can anyone direct me to a diagram or video?
If I'm understanding you correctly, you're saying,you want the STC to only control the fridge compartment and not the freezer compartment. The problem is there are not separate cooling circuits; there is only one compressor shared by both compartments. The cooling coils are usually located in the freezer compartment then the fridge portion is cooled by ducting running from the freezer compartment. They're baffled so that it restricts the cold air (so that your fridge portion doesn't freeze food).
If it has a blower to control air flow from freezer to fridge, you might be able to hook it up to the STC and have the STC control the blower. It might vary from model to model, but the freezer over fridge models I've seen don't use blowers, they just use baffles. Setting it to the coldest setting opens the baffle all the way while setting it to a warmer setting partially closes the baffle. Most people use the STC to switch power to the compressor.
If switching power to the compressor, you usually can't reliably say your freezer will stay cold enough to work as a freezer. For example, say your set temp on the STC is >= ambient temps, it's not going to switch the compressor on until the temp reading of the probe exceeds the set temp...which means your freezer compartment is warming and probably approaching equilibrium with the fridge compartment. Make sense? Say you're using it for a ferm chamber and you brewed a saison and your setpoint is 75F. Then let's say the ambient temp is 72F. It's going to be a long time between compressor cycling and the freezer compartment temps are going to climb close to 72F. On the other hand, if you're doing a lager at 52F and your ambient temps are 95F, it may cycle often enough that your freezer compartment stays close to freezer temps.