York Light Commercial Systems are comfortable, convenient and reliable. Units have quiet mode which can recue the fan speed and frequency of the compressor for quiet operation. A multi-speed fan helps satisfy various airflow requirements. Units are automatically returned to previous operating conditions after a power outage. High-efficiency DC fan motors (in most indoor and outdoor units) adjust speed and ESP automatically for reliable and efficient operation with low noise. Units offer a wide ambient temperature range with cooling from -15 degrees C to -48 degrees C. An expansion interface allows for connection to smoke detector, key slot, etc. A refrigerant leakage detector shuts down unit when refrigerant level is below 30% avoiding damage to the compressor.