I know this is an older thread but I am going to try this out and can’t quite figure the wiring. I am using the same components suggested by OP:
PC power supply for 12V DC supply
STC-3000 Temperature controller
Water pump
Pre-built thermoelectric cooling block
Those last three components all run on 12V DC.
I’m unsure how the 12V rail on the PSU should connect to the inputs on the other three components, and how the cooling output of the controller should connect to the pump and cooling block.
The controller runs off 12V (diagram is wrong in there) but seems to not output 12V, is it meant to actually power the pump and cooler or only switch them on and off? If powering them is it just passing through the same 12V supply it gets from the PSU?