Patent ID: 7765817

Claim:
A refrigeration system comprising: a refrigerant circuit, including a four-way selector valve provided therein, for operating in a refrigeration cycle, the four-way selector valve having a first port for allowing only suction refrigerant for a first compressor to flow thereinto, a second port for allowing only suction refrigerant to flow out thereof toward a second compressor, a third port for allowing only suction refrigerant for a third compressor to flow thereinto, and a fourth port for allowing only discharge refrigerant from the first to third compressors to flow thereinto; the four-way selector valve being configured to be switchable between a first position in which the first port is communicated with the second port and the third port is communicated with the fourth port and a second position in which the first port is communicated with the fourth port and the second port is communicated with the third port; and determining means for detecting the suction pressure of the second compressor during switching of the four-way selector valve and thereby determining whether the four-way selector valve has malfunctioned.