 They also use one or more electric or electronic sensors in place of the capillary tube and bulb for temperature sensing.Digital freeze stats utilizing microcontrollers or microprocessors can also perform more advanced functions than simply opening or closing switch contacts.Digital freeze stats can perform seemingly intelligent operations such as reversing the refrigerant flow and using some building heat to thaw a freon-to-liquid heat exchanger and then restoring the refrigerant flow to its normal direction once the danger of freezing the water coil has been averted.