This is the reply I got from our Thai friend about the temp differential when I asked. Of course when it gets here that will be thoroughly tested...
"Yes, you can wire at NC, the board has both NO and NC. It is analog board, it has no band gap,
example : you set at 50'C, > 50 'C relay close, < 50'C relay open. You have to adjust with the know temperature by thermometer."
