At least there might be a way to set this:
thermostatTemperatureRange
Object. Optional. Contains two float values that indicate the supported minimum and maximum temperature range for this device (in degrees Celsius):
minThresholdCelsius
maxThresholdCelsius
I will try to add this as a metadata config option.
But for now, you can not do anything about it. The “off” mode setting might do the trick.