PROBLEM TO BE SOLVED: To quickly cope with a user by efficiently performing repairing work, by imparting the failure diagnostic function of a compressor 1 to a thermo-compression type refrigerating unit.;SOLUTION: A failure diagnostic method comprises a step S12 as a current variable means for variably supplying a control current value imparted to a variable control valve 154 for variably controlling compression capacity of the compressor 1 in the size of a plurality of stages, a step S13 as a low pressure detecting means for detecting a low pressure side pressure value in a thermo-compression type refrigerating cycle with every stage and a step S14 as a normality determining means for determining whether or not the relationship between a supplied control current value and the detected low pressure side pressure value falls within an normal range from a comparison with a predetermined characteristic curve. When determined as being outside the normal range in the step S14, the compressor 1 is determined as failure. Thus, whether or not the compressor 1 incorporated into the thermo-compression type refrigerating cycle causes the failure, can be easily determined.;COPYRIGHT: (C)2009,JPO&INPIT
展开▼
