If you can change your digital clock from Daylight time to Standard then the unit is going to be easy to program. Rigorously tested with the probes in a chamber having both cooling and heating inputs. It appears the "ON" for cooling is the programmed input PLUS the differential. I.E. 75 degree program with a 5 degree differential will not start the cooling cycle until 80 degrees. Cooling is switched "OFF" at the programmed value (75). Repeats very well so knowing how it works enables the user to program it to do what they want. We are using two units to control four stages of cooling in a greenhouse. On our application the outputs from the 608's drive relay coils to thermostatically open and close ridge vent and eave vent motorized windows. More 608's are planned for mist cooling stages.