The low ambient option consists of circuitry to protect the compressor in a low ambient temperature environment. Heat is applied inside the compressor, where it is needed, to protect it from damage or wear due to stalls and hard starts after long periods in the non-cooling state.
This works together with the pressure controlled condenser fan in Thermal Edge air conditioners. The condenser fan cycles off in low ambient temperature conditions, thus allowing rapid warm up. This also reduces the current inrush by not starting the condenser fan when the compressor is turned on.