PURPOSE: To improve the rise-up characteristics of the title machine upon starting by a method wherein a bypass circuit, connecting a high-pressure pipeline including a compressor to a low-pressure pipeline including a pressure reducing device for room cooling through a solenoid valve, is provided while the solenoid valve is controlled so as to be opened when a temperature in an outdoor heat exchanger is higher than a predetermined value and the like.
CONSTITUTION: A bypass circuit 11, connecting a high-pressure side pipeline, to which a compressor 1 and a four-way valve 2 are connected, to a low-pressure side pipeline, to which a choking device 4 for room cooling and a pressure reducing device 6 are connected, through a solenoid valve 10, is provided. A temperature detecting device 12 is provided in the liquid pipeline of an outdoor heat exchanger 3 and the output signal of the same is inputted into a solenoid valve controlling means 13 to control the opening and/or closing of the solenoid valve 10. When a detecting temperature detected by the temperature detecting means 12 is lower than a first set temperature before starting room cooling operation, refrigerant is existing in an indoor heat exchanger 7 side and, therefore, the solenoid valve 10 is opened to bypass high-pressure gas and reduce the reduction of a low pressure whereby the rise up characteristic upon starting operation is improved. On the other hand, the solenoid valve 10 is controlled so as to be opened when the detecting temperature is lower than a second set temperature upon room heating.
ISHIKAWA KOJI
SUGINO MASAHIKO
