| 摘要 |
PURPOSE:To allow some of indoor units to perform cooling operation and the others to perform heating operation at the same time by a method wherein a first pressure detector is provided between a first manifold and second flow control valve, a second pressure detector is installed between the second flow control valve and a fourth flow control valve, and the fourth control valve is controlled so that the pressure difference detected by the pressure detectors is kept within a specified range in the case all the indoor units perform only heating operation. CONSTITUTION:A first connecting pipe 6 is allowed to be changed over to low pressure side and a second connecting pipe 7 to high pressure side. A first pressure detector 25 is located between a first manifold 10 and a second flow control valve 13, and a second pressure detector 26 between the second flow control valve 13 and a fourth flow control valve 17. In the case all indoor units perform only heating operation, the fourth flow control valve 17 is controlled so that the pressure difference DELTAP32 detected by the first and second pressure detectors is kept between the first target value DELTAPMd that is previously set larger than a certain value DELTAP1 and the second target value DELTAPMu that is previously set smaller than a value DELTAP2. |
