I have a question about an old federal pacific baseboard heater thermostat's wiring. I disconnected this thermostat 2 weeks ago, thinking that we were going to remove the heater. Now we've decided to keep the heater, and I don't remember how the thermostat was wired. The therm box has two lines in it: one in, one out. Each line has 1 black, one white, and one bare ground. I have attached a pic of the back of the thermostat. It only has 3 places to connect. Poles 2, 3, and 4. Can anyone help me out and tell me what hooks to each pole?