One to controls the A/C (heater, foil taped to a/c temp sensor). The other in series to monitor the evaporator temp. If the evaporator gets to 32 degrees it turns off the power to the heater.
The heater is just a resistor powered by the iphone charger :)
A/C is plugged into the wall runs all...
Finally!! 1st brew went well. Only hiccup was a leaky connection on the new plate chiller. The backup immersion chiller saved the brew day. 5 gallons of IPA in the fermenter. :)