Refrigeration cycle apparatus

Abstract

A refrigeration cycle apparatus includes an outdoor unit a plurality of indoor units a relay unit a refrigerant circuit and a controller The relay unit includes a plurality of high-pressure valves and a plurality of low-pressure valves The controller when an operation state of at least one of the indoor units is changed from a first state to a second state, judges, based on a degree of supercooling of an outlet of the outdoor heat exchanger or the indoor heat exchanger or based on a degree of superheating of a suction side of the compressor, whether an abnormality is present in the plurality of high-pressure valves or the plurality of low-pressure valves.

1 . A refrigeration cycle apparatus, comprising:
 an outdoor unit including a compressor and an outdoor heat exchanger,   a plurality of indoor units each including an indoor heat exchanger and an expansion device,   a relay unit intervening between the outdoor unit and each of the plurality of indoor units and serving to cause refrigerant from the outdoor unit to branch off into each of the indoor units,   a refrigerant circuit in which the compressor, the outdoor heat exchanger, the expansion device and the indoor heat exchanger are connected by refrigerant pipes and through which refrigerant circulates, and   a controller configured to control the plurality of indoor units,   wherein   the relay unit includes   a plurality of high-pressure valves each provided in a corresponding one of a plurality of high-pressure pipes connecting a high-pressure side of the outdoor unit and each of the indoor units, and   a plurality of low-pressure valves each provided in a corresponding one of a plurality of low-pressure pipes connecting a low-pressure side of the outdoor unit and each of the indoor units, and   the controller is configured to, when an operation state of at least one of the indoor units is changed from a first state to a second state, judge, based on a degree of supercooling of an outlet of the outdoor heat exchanger or the indoor heat exchanger that functions as a condenser or based on a degree of superheating of a suction side of the compressor, whether an abnormality is present in the plurality of high-pressure valves or the plurality of low-pressure valves.   
     
     
         2 . The refrigeration cycle apparatus of  claim 1 , wherein 
 the high-pressure valves and the low-pressure valves connected to the indoor units that are under suspension are controlled to be in a closed state,   the first state is an operating state, and   the second state is a suspended state.   
     
     
         3 . The refrigeration cycle apparatus of  claim 1 , wherein 
 the high-pressure valves and the low-pressure valves connected to the indoor units that are under suspension are controlled to be in a closed state,   the first state is a suspended state, and   the second state is an operating state.   
     
     
         4 . The refrigeration cycle apparatus of  claim 1 , wherein 
 in a case in which the refrigerant circuit is configured such that the outdoor heat exchanger serves as a condenser and all of the high-pressure valves are in a closed state, the first state is a state where one of the low-pressure valves connected to the at least one of the indoor units is controlled to be in an open state and the second state is a state where one of the low-pressure valves connected to the at least one of the indoor units is controlled to be in a closed state.   
     
     
         5 . The refrigeration cycle apparatus of  claim 1 , wherein 
 in a case in which the refrigerant circuit is configured such that the outdoor heat exchanger serves as a condenser and all of the high-pressure valves are in a closed state, the first state is a state where one of the low-pressure valves connected to the at least one of the indoor units is controlled to be in a closed state and the second state is a state where one of the low-pressure valves connected to the at least one of the indoor units is controlled to be in an open state.   
     
     
         6 . The refrigeration cycle apparatus of  claim 1 , wherein 
 in a case in which the refrigerant circuit is configured such that the outdoor heat exchanger serves as an evaporator and all of the high-pressure valves are in a closed state, the first state is a state where one of the high-pressure valves connected to the at least one of the indoor units is controlled to be in an open state and the second state is a state where one of the high-pressure valves connected to the at least one of the indoor units is controlled to be in a closed state.   
     
     
         7 . The refrigeration cycle apparatus of  claim 1 , wherein 
 in a case in which the refrigerant circuit is configured such that the outdoor heat exchanger serves as an evaporator and all of the high-pressure valves are in a closed state, the first state is a state where one of the high-pressure valves connected to the at least one of the indoor units is controlled to be in a closed state and the second state is a state where one of the high-pressure valves connected to the at least one of the indoor units is controlled to be in an open state.   
     
     
         8 . The refrigeration cycle apparatus of  claim 1 , wherein 
 the refrigerant circuit is configured such that the outdoor heat exchanger serves as a condenser, and   in a case in which the degree of supercooling of the outlet of the outdoor heat exchanger that functions as a condenser when all of the indoor units are in an operating state or the degree of superheating of the suction side of the compressor is less than a threshold set in advance, the controller is configured to, in a case in which when the operation state of at least one of the indoor units is changed from an operating state that is the first state to a suspended state that is the second state, the degree of supercooling of the outlet of the outdoor heat exchanger that functions as a condenser or the degree of superheating of the suction side of the compressor is less than the threshold, judge that an abnormality is present in one of the high-pressure valves connected to one of the indoor units that is in an operating state and, in a case in which the degree of supercooling of the outlet of the outdoor heat exchanger that functions as a condenser or the degree of superheating of the suction side of the compressor is not less than the threshold, judge that an abnormality is present in one of the high-pressure valves connected to one of the indoor units that is in a suspended state.   
     
     
         9 . The refrigeration cycle apparatus of  claim 1 , wherein 
 the refrigerant circuit is configured such that the outdoor heat exchanger serves as a condenser, and   in a case in which all of the indoor units are in a suspended state, the controller is configured to, in a case in which when the operation state of at least one of the indoor units is changed from a suspended state that is the first state to an operating state that is the second state, the degree of supercooling of the outlet of the outdoor heat exchanger that functions as a condenser or the degree of superheating of the suction side of the compressor is less than a threshold set in advance, judge that an abnormality is present in one of the high-pressure valves connected to one of the indoor units that is in an operating state and, in a case in which the degree of supercooling of the outlet of the outdoor heat exchanger that functions as a condenser or the degree of superheating of the suction side of the compressor is not less than the threshold, judge that no abnormality is present in one of the high-pressure valves connected to one of the indoor units that is in an operating state.   
     
     
         10 . The refrigeration cycle apparatus of  claim 1 , wherein 
 the refrigerant circuit is configured such that the outdoor heat exchanger serves as an evaporator, and   in a case in which the degree of supercooling of the outlet of the indoor heat exchanger that functions as a condenser when all of the indoor units are in an operating state or the degree of superheating of the suction side of the compressor is less than a threshold set in advance, the controller is configured to, in a case in which when the operation state of at least one of the indoor units is changed from an operating state that is the first state to a suspended state that is the second state, the degree of supercooling of the outlet of the indoor heat exchanger that functions as a condenser or the degree of superheating of the suction side of the compressor is less than the threshold, judge that an abnormality is present in one of the low-pressure valves connected to one of the indoor units that is in an operating state and, in a case in which the degree of supercooling of the outlet of the indoor heat exchanger that functions as a condenser or the degree of superheating of the suction side of the compressor is not less than the threshold, judge that an abnormality is present in one of the low-pressure valves connected to one of the indoor units that is in a suspended state.   
     
     
         11 . The refrigeration cycle apparatus of  claim 1 , wherein 
 the refrigerant circuit is configured such that the outdoor heat exchanger serves as an evaporator, and   in a case in which all of the indoor units are in a suspended state, the controller is configured to, in a case in which when the operation state of at least one of the indoor units is changed from a suspended state that is the first state to an operating state that is the second state, the degree of supercooling of the outlet of the indoor heat exchanger that functions as a condenser or the degree of superheating of the suction side of the compressor is less than a threshold set in advance, judge that an abnormality is present in one of the low-pressure valves connected to one of the indoor units that is in an operating state and, in a case in which the degree of supercooling of the outlet of the indoor heat exchanger that functions as a condenser or the degree of superheating of the suction side of the compressor is not less than the threshold, judge that no abnormality is present in one of the low-pressure valves connected to one of the indoor units that is in an operating state.