9. OPERATIONChild lock functionPress and hold “+” and “-” buttons together for 3 secondsor more to activate the child lock function and lock all buttonson the wire controller.Press the buttons again for 3 seconds or more to deactivatethe child lock function.When the child lock function is activated,the mark appears.15PTC function (on some models)Press the Follow me/PTC button for 2 seconds or more to activate thePTC function,when the unit is under the Heat mode.Press the buttons again for 2 seconds or more to deactivate the PTCfunction.When the PTC function is activated,the mark appears.°C & °F scale selection (on some models)Press and hold and buttons togetherfor 3 seconds will alternate the temperature displaybetween the ℃&℉ scale.