Patent ID: 7472559

Claim:
An air-conditioning system comprising: a controller; an indoor unit comprising: an evaporator; an indoor expansion valve; and an indoor fan; and an outdoor unit comprising: a constant speed compressor; a condenser; an outdoor expansion valve; and an outdoor fan, wherein in response to receiving information about current discharge and sucking pressures of the constant speed compressor, the controller determines whether the current discharge and sucking pressures are within acceptable pressure ranges for the constant speed compressor, wherein in a cooling mode, in response to the controller determining that both the current sucking pressure and the discharge pressure are less than first predetermined thresholds, the indoor expansion valve's pulse is increased, the constant speed compressor is turned off, and the outdoor fan's generated air flow is decreased, wherein in a heating mode, in response to the controller determining that both the current sucking pressure and the discharge pressure are less than second predetermined thresholds, the outdoor expansion valve's pulse is increased, the constant speed compressor is turned on, the outdoor expansion valve's pulse is increased, and the indoor fan's generated air flow is decreased.