KR20100056204A - Multi-air-conditioner and method for diagnosising refrigerants leakage thereof - Google Patents

Abstract

PURPOSE: A multi-air-conditioner and a refrigerant leakage diagnosis method thereof are provided to easily diagnosis refrigerant leakage by a sensor which is installed on a lower pressure side of a suspended outdoor unit. CONSTITUTION: A multi-air-conditioner comprises: outdoor units(110,120); indoor units; a refrigerant pipe which interlinks the outdoor units and indoor units; and a leakage diagnosis unit which is installed in a suspended outdoor unit and includes a first sensor which is installed in the lower side of the suspended outdoor unit, outdoor temperature sensors(112a,122a), and a controller. If at least one of the outdoor units which heating-operates among the outdoor units and the others are stopped, the leakage diagnosis unit decides whether the leakage of refrigerant is or not by comparing the outdoor temperature and variable value which changes according to the amount of the refrigerant which flowing in into the suspended outdoor unit.

Description

Multi-air conditioner and method for diagnosis of refrigerants leakage

The present invention relates to a multi-type air conditioner and a method for diagnosing a refrigerant leakage thereof, and more particularly, to a multi-type air conditioner and a method for diagnosing a refrigerant leakage of a refrigerant in an outdoor unit which is stopped in operation among a plurality of outdoor units.

The residential space in the house is enlarged and the air conditioning system is widely adopted by using a number of indoor units due to the change of the air conditioning environment of the building. The air-conditioning capability of the air conditioner required by the occupants becomes greater, such as being able to respond quickly.

Accordingly, a multi-type air conditioner has been developed that includes a modular outdoor unit having a plurality of outdoor units together to secure a large amount of driving capability, thereby increasing or decreasing the driving capability of the plurality of outdoor units according to the indoor operation load.

The modular outdoor unit is connected to the indoor side and the refrigerant pipe. The plurality of outdoor units are each provided with a refrigerant circuit for discharging the refrigerant to an indoor side connected to the refrigerant pipe and sucking the refrigerant supplied through the refrigerant pipe. Such refrigerant circuits include several components that control the flow of refrigerant. Therefore, a defect may occur in a component of the refrigerant circuit, and a phenomenon may occur that the refrigerant of the indoor indoor unit flows into the stationary outdoor unit due to such a defect. Therefore, a countermeasure is required.

An aspect of the present invention is to provide a multi-type air conditioner for diagnosing a refrigerant leak in an outdoor unit which is stopped in operation among a plurality of outdoor units, and a method for diagnosing the refrigerant leakage thereof.

To this end, the multi-type air conditioner according to an embodiment of the present invention, in the multi-type air conditioner connected to the plurality of outdoor units, the plurality of indoor units, the plurality of outdoor units and the plurality of indoor units by a refrigerant pipe, at least one operation of the plurality of outdoor units When the outdoor unit is heated and the remaining outdoor unit is in operation stop, the outdoor unit includes a leakage diagnosis device that determines the leakage of the refrigerant by comparing the outdoor temperature with a variable value changed according to the amount of refrigerant introduced into the stopped outdoor unit.

The leak diagnosis device is provided in the outdoor unit in which the operation is stopped.

The leak diagnosis apparatus includes a control unit that determines a refrigerant leak by comparing the output of the first sensor, the outdoor temperature sensor, and the sensors installed on the low pressure side of the outdoor unit that is stopped.

The first sensor is a pressure sensor for detecting the suction pressure of the accumulator connected to the compressor of the operation stop outdoor unit.

The first sensor is a temperature sensor for detecting the suction temperature of the accumulator connected to the compressor of the operation stop outdoor unit.

The leak diagnosis apparatus compares a pressure sensor for detecting the suction pressure of the accumulator installed on the low pressure side of the outdoor unit that is stopped, a temperature sensor for detecting the suction temperature of the accumulator, an outdoor temperature sensor, and outputs of the sensors. And a control unit for determining a refrigerant leak.

To this end, the multi-type air conditioner according to an embodiment of the present invention is a multi-type air conditioner connected between a high-pressure tube and a low-pressure tube between an outdoor side provided with a plurality of outdoor units and an indoor side provided with a plurality of indoor units, at least one of the plurality of outdoor units. When the outdoor unit of the heating operation and at least one outdoor unit is stopped at the same time, the leakage of the refrigerant is determined according to the relationship between the amount of refrigerant flowing into the outdoor unit is stopped through the high-pressure pipe connected to the outdoor unit for heating operation and the outdoor temperature Includes leak diagnosis device.

The operation stop outdoor unit further includes a compressor, a check valve installed in the refrigerant leakage path, a four-way valve, a bypass circuit for recovering oil to the compressor suction side, and an accumulator connected to the suction side of the compressor, The leak diagnosis apparatus includes a first sensor installed at the suction side of the accumulator connected to the low pressure pipe, a control unit for comparing the output of the first sensor with a reference value set corresponding to the outdoor temperature to determine the leakage of the refrigerant. Include.

The first sensor is a pressure sensor or a temperature sensor.

The bypass circuit flows out refrigerant of the operating outdoor unit introduced through the four-way valve and the check valve to the compressor and the accumulator.

To this end, the multi-type air conditioner according to an embodiment of the present invention, in the multi-type air conditioner for controlling the number of operation of the plurality of outdoor units in accordance with the indoor operation load, the leakage to determine the refrigerant leakage of the outdoor unit of the operation stop of the plurality of outdoor units Including a diagnostic device, The leak diagnosis device, the sensor for detecting the suction pressure or suction temperature of the accumulator due to the refrigerant flowing into the outdoor unit is stopped from the heating operation outdoor unit, the outdoor temperature sensor for sensing the outdoor temperature, and And a controller configured to determine a refrigerant leak of the outdoor unit which is stopped in operation according to output values of the sensors.

To this end, the refrigerant leakage diagnosis method of the multi-type air conditioner according to an embodiment of the present invention determines whether the heating operation; Sense outdoor temperature; And determining the refrigerant leakage to the operation stop outdoor unit by comparing the outdoor temperature with a variable value changed according to the refrigerant filled in the accumulator in which the refrigerant introduced into the outdoor unit during operation stops.

The variable value is a saturation temperature corresponding to the suction pressure of the accumulator, and when the variable value is greater than the first margin plus the outdoor temperature, it is determined that the refrigerant leaks.

The variable value is the suction temperature of the accumulator, and if the variable value is greater than the value obtained by adding the second margin to the outdoor temperature, it is determined that the refrigerant leaks.

To this end, the refrigerant leakage diagnosis method of the multi-type air conditioner according to an embodiment of the present invention, the refrigerant of the multi-type air conditioner connected between the outdoor side provided with a plurality of outdoor units and the indoor side provided with a plurality of indoor units by a high pressure tube and a low pressure tube A leak diagnosis method, comprising: determining whether an operation mode is heating operation; When the at least one outdoor unit of the plurality of outdoor units is heated and the at least one outdoor unit is in operation stop, a variable value which varies according to the amount of refrigerant introduced into the accumulator installed on the low pressure side of the stopped outdoor unit is compared with the outdoor temperature; And determining the refrigerant leakage to the operation stop outdoor unit according to the comparison result.

Indicating leakage of the refrigerant; Determining whether the leakage time of the refrigerant has elapsed a predetermined time; Forcibly stopping the driving outdoor unit when the leakage time passes the set time;

As described above, the present invention can easily diagnose refrigerant leakage by using a sensor provided on the low pressure side of an outdoor unit in which the operation is stopped.

In addition, the present invention can protect the outdoor unit by forcibly stopping the operation of the outdoor unit in operation when the refrigerant leakage time elapses.

Hereinafter, with reference to the accompanying drawings an embodiment according to the present invention will be described in detail.

As shown in FIG. 1, the multi-type air conditioner is configured by connecting the modular outdoor unit 100 and the plurality of indoor units 210, 220, 230, and 240 to the refrigerant pipes 301 and 302. Here, the modular outdoor unit and the plurality of indoor units may communicate with the outdoor control unit and the indoor control unit using a communication line (not shown), and such a configuration may adopt a generally known configuration.

The modular outdoor unit 100 includes two outdoor units 110 and 120. Here, the number of outdoor units provided by the modular outdoor unit is not limited and may not be limited so that each outdoor unit has the same air conditioning capability, and thus may be set in consideration of the air conditioning environment of the indoor unit in which the outdoor unit is installed.

The plurality of outdoor units 110 and 120 share a high pressure tube 301 for supplying a high pressure refrigerant to a indoor side during a heating operation, and configure a refrigerant circuit to share a low pressure tube 302 for receiving a low pressure refrigerant to the indoor side. .

Since the indoor driving load varies according to the number of indoor units to operate, the outdoor units 110 and 120 do not necessarily need to be driven or stopped at the same time. Therefore, some outdoor units or all outdoor units are operated with respect to a plurality of outdoor units according to an operating load.

2 is a detailed configuration diagram of the outdoor unit module of FIG. 1 according to an embodiment of the present invention, and FIG. 3 is a block diagram of a multi-type air conditioner according to the present invention.

Referring to FIG. 2, the plurality of outdoor units 110 and 120 are structurally identically configured.

Each outdoor unit 110, 120 includes a compressor 111, 121, an outdoor heat exchanger 112, 122, and an outdoor fan 113, 123 that can vary in capacity.

On the discharge side of each of the compressors 111 and 121, oil separators 111a and 121a, check valves 116 and 126 for preventing backflow of the refrigerant, and four-way valves 115 for changing the flow of the refrigerant depending on the operation mode. 125).

The four-way valves 115 and 125 supply the high pressure refrigerant to the high pressure tube 301 during the heating operation, and supply the outdoor heat exchanger 112 and 122 during the cooling operation. Switch the flow path. The specific structure of such a four-way valve can employ | adopt a structure generally known.

Each outdoor unit 110, 120 includes an accumulator 114, 124 connected to the suction side of the compressor.

The inlet of the accumulators 114, 124 is connected to the four-way valve 115 via branch circuits A1 and A2, and the outlet is connected to the compressor suction side. The low pressure refrigerant provided from the indoor side through the branch circuit A1 is sucked into the accumulators 114 and 124. At the inlet of the accumulator, pressure sensors 117 and 127 are provided to detect the refrigerant pressure. The gas refrigerant separated from the accumulator is provided to the compressor suction side.

In the hot gas bypass circuits B1 and B2 connecting the discharge side and the suction side of the compressors 11 and 121, bypass valves 118 and 128 for opening and closing the flow path are provided.

In addition, the oil bypass circuits C1 and C2 connecting between the compressor discharge side and the suction side provide a flow path for recovering oil by sending oil separated in the oil separators 111a and 121a to the compressor suction side.

Reference numerals 119 and 129 are for controlling the flow of the refrigerant supplied through the low pressure tube 302 during heating operation, and is an electric valve that serves to block the refrigerant when the outdoor unit is stopped.

Reference numerals 112a and 122a denote outdoor temperature sensors for sensing outdoor temperatures.

Reference numeral 101 is an input unit for inputting a user command, and reference numeral 102 is a display unit for displaying an operating state of the air conditioner and refrigerant leakage.

The components configured in each of the outdoor units 110 and 120 described above are electrically connected to the outdoor controller 100A, and the respective components are controlled by the outdoor controller. In the present exemplary embodiment, one outdoor controller exemplarily integrates and controls a plurality of outdoor units, but the present invention is not limited thereto. For example, a plurality of outdoor control units that individually control each outdoor unit may communicate with each other to control driving ability.

The outdoor controller 100A communicates with a plurality of indoor controllers 210A, 220A, 230A, 240A that control the plurality of indoor units, respectively.

When the number of indoor unit indoor operation unit is changed, the driving load may also vary accordingly. Accordingly, the outdoor controller 100A may drive some outdoor units of the plurality of outdoor units and stop some outdoor units in order to vary the capacity of the outdoor unit appropriately for the indoor driving load.

4 is a diagram illustrating a refrigerant cycle and a flow of leaked refrigerant in which one outdoor unit is heated and operated while the other outdoor unit is stopped in the multi-type air conditioner according to the present invention.

Referring to FIG. 4, one outdoor unit 110 is heated and the other outdoor unit 120 is stopped operating.

In the outdoor unit 110 for heating operation, the refrigerant discharged from the compressor 111 is transferred to the four-way valve 115 via the check valve 116. The four-way valve 115 operates the slider inside to correspond to the heating operation to supply the introduced refrigerant to the high pressure pipe 301. The refrigerant via the high pressure pipe 301 is provided to the driving indoor unit side (refer to the arrow in the solid line).

The low pressure refrigerant delivered from the driving indoor unit side is provided to each outdoor unit 110, 120 via the low pressure tube 302. At this time, the electric valve 119 of the driving outdoor unit 110 is in an open state, and the electric valve 129 of the outdoor unit 120 that has been stopped is in a closed state.

Accordingly, the refrigerant supplied through the low pressure tube 203 is heat-exchanged with the outdoor air in the outdoor heat exchanger 112 via the electric valve 119, and is then sucked into the accumulator 114 via the branch circuit A1. The gas refrigerant separated from the accumulator 114 is then sucked into the compressor 111 (see the broken arrow).

Since the electric valve 129 is closed in the outdoor unit 120 which is stopped, the refrigerant supplied through the low pressure tube 203 is not transmitted to the outdoor heat exchanger 122. In addition, since the compressor 121 is stopped, refrigerant is not discharged.

However, as one of the components constituting the refrigerant circuit of the outdoor unit 120 is stopped, when the slider of the four-way valve 125 is torn and damaged, the high-pressure refrigerant via the high-pressure pipe 302 flows into the discharge side of the compressor 121. . The introduced high pressure refrigerant may be blocked by no more inflow by the check valve 126. If the shutoff valve 125 is also defective, the high pressure refrigerant flows into the compressor discharge side, and then passes through the oil bypass circuit C2 connected to the oil separator. Some of the high pressure refrigerant via the oil bypass circuit C2 flows into the stationary compressor and the remaining high pressure refrigerant flows into the accumulator 124 (see arrow of dashed line).

As such, when the high pressure refrigerant to be provided to the indoor unit through the high pressure tube 302 leaks and flows into the stationary compressor 121, it is condensed inside the compressor and accumulates in the liquid phase. As a result, the oil is foamed when the compressor 121 is started to cause lubrication failure due to the lack of oil in the compressor.

In addition, the high-pressure refrigerant introduced into the accumulator 124 is condensed and filled with a liquid phase. When the compressor 121 is started in this state, the liquid refrigerant filled in the accumulator is sucked into the compressor to cause starting failure or compressor failure. Cause.

In addition, the high pressure refrigerant leaks from the outdoor unit in operation, resulting in a shortage of refrigerant in the operating outdoor unit. Compressor performance decreases as the compressor discharge temperature of the operation outdoor unit increases due to the lack of refrigerant and the suction pressure decreases.

In the outdoor unit thus stopped, it is required to self-diagnose the phenomenon in which the high-pressure refrigerant flows in and leaks, in case the components do not operate normally.

According to the present embodiment, the high pressure refrigerant is introduced into the outdoor unit 120 in which the operation is stopped and filled in the accumulator 124 installed on the low pressure side, and the pressure change of the accumulator 124 appears. At this time, the saturation temperature corresponding to the suction pressure detected by the pressure sensor 127 installed at the inlet of the accumulator 124 is the first margin t1 to the outdoor temperature To detected by the outdoor temperature sensor 122a. If the temperature is greater than the temperature, it is determined that the refrigerant leaks. The leakage control of the refrigerant is performed by the outdoor controller 100A.

When the outdoor controller 100A determines that the refrigerant leaks, the outdoor controller 100A displays information in which the refrigerant leaks in the outdoor unit which has been stopped by the display unit 102 so that the administrator can check the leakage. In addition, the outdoor control unit 100A counts the leakage time after the refrigerant leakage occurs, and forcibly stops the operation of the outdoor unit in operation to protect the outdoor unit when the leakage time passes the preset limit operation time. .

FIG. 5 is a flowchart illustrating a method for diagnosing a leak of a refrigerant in a multi-type air conditioner according to an exemplary embodiment of the present invention, and will be described based on the control by the outdoor controller 100A.

First, when the operation mode is determined and the heating operation is performed, each component is operated in response to the heating operation cycle, for example, the valves installed in the refrigerant circuit are driven to control the refrigerant flow, and the compressor of the operation outdoor unit is driven ( 501) (503) (505).

Subsequently, the outdoor control unit 100A communicates with the indoor control units 210A, 220A, 230A, and 240A to determine whether to stop some outdoor units according to the indoor operating load (507). If there is no outdoor unit to stop operation, it is determined whether to stop operation for the entire system (508). If the determination is to continue to operate the entire system, the process returns to step 507.

If it is determined that the operation stops of the entire system, operation of each component for the outdoor unit is stopped (510).

If the indoor operation load is not large and it is necessary to stop some outdoor units, each component is controlled by stopping the compressor and closing the electric valve 129 for the operation stop outdoor unit, and the signal output from the pressure sensor 127 is controlled. In operation 509, the saturation temperature of the suction pressure of the accumulator 124 is found by searching a table stored in advance. Then, the outdoor control unit 100A compares the searched saturation temperature with the temperature obtained by adding the first margin t1 to the outdoor temperature To detected by the outdoor temperature sensor 122a to determine whether there is leakage (511) ( 513). If the saturation temperature is greater, it is determined that the refrigerant leakage has occurred, and the leakage state is displayed through the display unit 102, and at the same time, the leakage time is measured using the leakage time counter (515).

Then, it is determined whether the entire system is in operation stop (517). If the determination does not correspond to the operation stop, it is determined whether the leakage time measured after the leakage of the refrigerant has elapsed from the preset limit operation time (519), and the measurement If the leakage time has not passed the limit operation time, the process proceeds to step 513. If the measured leakage time has passed the limit operation time, the operation outdoor unit is forcibly stopped to protect the outdoor unit (521).

Meanwhile, when the refrigerant leaks into the outdoor unit in which the refrigerant is stopped from the outdoor unit in operation, the inlet pressure is changed in the accumulator as in the above-described embodiment, and then the inlet temperature is changed after a while. Considering this point, as described above, the refrigerant leakage may be determined based on the suction temperature detected by the temperature sensor by employing the inlet temperature sensor instead of only the pressure sensor. With this in mind, the following embodiment focuses on the method of determining the refrigerant leakage according to the intake temperature of the accumulator.

6 is a detailed configuration diagram of the outdoor unit module of FIG. 1 according to another embodiment of the present invention, and FIG. 7 is a flowchart illustrating a method of diagnosing a refrigerant leak in a multi-type air conditioner according to another embodiment of the present invention. .

Other embodiments described with reference to FIGS. 6 and 7 have most of the technical features described above with reference to FIGS. 2 to 5, and the descriptions thereof will be omitted, and thus descriptions will be omitted based on configurations that are discriminated.

The configuration of the outdoor unit shown in FIG. 6 replaces the temperature sensors 117a and 127a at the inlet of the accumulators 114 and 124 instead of the pressure sensors 117 and 127 as compared with the configuration of FIG. It is the same in other configurations except that. Therefore, the description of each component of the same reference will be briefly described in the range to avoid duplication.

The operation method for the plurality of outdoor units 110a and 120a constituting the modular outdoor unit 100 is made by the outdoor controller, and this control method is made equivalent to the previous embodiment. For example, when one outdoor unit 110a is heated and the other outdoor unit 120a is shut down, the flow of the refrigerant is the same as that of the refrigerant shown in FIG. 4. Here, in the outdoor unit 120a which has stopped operating, the high pressure refrigerant is sent to the suction side of the compressor 121 and the accumulator 124 via the oil bypass circuit C2 due to the defect of the four-way valve 125 and the shutoff valve 126. Is the same.

 In this case, when the refrigerant leaks, the suction temperature of the accumulator 124 changes, and the change of the suction temperature is detected by the temperature sensor 127a and provided to the outdoor controller. Accordingly, the outdoor controller determines that the leakage of the refrigerant occurs when the outdoor temperature To detected by the outdoor temperature sensor 122a is greater than the temperature obtained by adding the second margin t2 (greater than the first margin).

Referring to FIG. 7, when the operation mode is a heating operation, valves installed in the refrigerant circuit and a compressor of the operation outdoor unit are driven to control the refrigerant flow in response to the heating operation cycle (601) (603) (605).

The outdoor control unit communicates with each indoor control unit to determine whether to stop some outdoor units according to the indoor operating load (607). If it is determined (608) that the determination continues to operate the entire system, the flow returns to step 607.

If it is determined that the entire system stops operation, operation of each component of the outdoor unit is stopped (610).

If it is necessary to stop the outdoor unit, the compressor is stopped for the outdoor unit, the electric valve 129 is closed, and the respective components are controlled, and the suction temperature of the accumulator 124 output by the temperature sensor 127a is provided. 509. Then, the outdoor controller compares the suction temperature and the outdoor temperature To detected by the outdoor temperature sensor 122a to a temperature obtained by adding a second margin t2 to determine whether the leakage occurs (611, 613). If the suction temperature is greater, it is determined that the refrigerant leak has occurred, and the leak state is displayed through the display unit 102, and at the same time, the leak time is measured using the leak time counter (615).

Then, it is determined whether the entire system is in operation stop (617). If the determination does not correspond to the operation stop, it is determined whether the leakage time measured after the leakage of the refrigerant has elapsed from the preset limit operation time (619), and the measurement If the leakage time has not passed the limit operation time, the process proceeds to step 613. If the measured leakage time has passed the limit operation time, the operation outdoor unit is forcibly stopped to protect the outdoor unit (621).

Although not described in the above-described embodiment, the refrigerant leakage is determined by considering both the saturation temperature corresponding to the pressure sensed by the pressure sensor and the suction temperature sensed by the temperature sensor at the same time having a pressure sensor and a temperature sensor at the inlet of the accumulator In addition, according to the judgment, it is also possible to perform a process corresponding to the refrigerant leakage.

1 is a block diagram of a multi-type air conditioner.

2 is a detailed block diagram of the outdoor unit module of FIG. 1 according to an exemplary embodiment of the present invention.

3 is a block diagram of a multi-type air conditioner according to the present invention.

4 is a diagram illustrating a refrigerant cycle and a flow of leaked refrigerant in which one outdoor unit is heated and operated while the other outdoor unit is stopped in the multi-type air conditioner according to the present invention.

5 is a flowchart illustrating a method of diagnosing a refrigerant leak in a multi-type air conditioner according to an exemplary embodiment of the present invention.

6 is a detailed block diagram of the outdoor unit module of FIG. 1 according to another embodiment of the present disclosure.

7 is a flowchart illustrating a method of diagnosing a refrigerant leak in a multi-type air conditioner according to another embodiment of the present invention.

Description of the Related Art [0002]

100: outdoor unit module 110, 120: outdoor unit

301: high pressure tube 302: low pressure tube

Claims (16)

In the multi-type air conditioner connecting a plurality of outdoor units, a plurality of indoor units, the plurality of outdoor units and the plurality of indoor units by a refrigerant pipe, When at least one outdoor unit of the plurality of outdoor units is heated and the other outdoor units are stopped, a leakage diagnosis is performed to determine the leakage of the refrigerant by comparing a variable value which varies according to the amount of refrigerant introduced into the stopped outdoor unit and the outdoor temperature. Multi-type air conditioner comprising a device. The method of claim 1, The leak diagnosis device is a multi-type air conditioner provided in the outdoor unit is stopped. 3. The method of claim 2, The leak diagnosis apparatus includes a control unit for determining a refrigerant leakage by comparing the output of the first sensor, the outdoor temperature sensor, and the sensors installed on the low pressure side of the outdoor unit is stopped operation. The method of claim 3, wherein The first sensor, And a pressure sensor detecting a suction pressure of an accumulator connected to the compressor of the operation stop outdoor unit. The method of claim 3, wherein The first sensor, And a temperature sensor detecting a suction temperature of an accumulator connected to the compressor of the operation stop outdoor unit. The apparatus of claim 2, wherein the leak diagnosis device comprises: a pressure sensor for detecting an intake pressure of an accumulator installed on the low pressure side of the stopped outdoor unit, a temperature sensor for detecting an intake temperature of the accumulator, an outdoor temperature sensor, and the A multi-type air conditioner including a control unit for comparing the output of the sensors to determine the refrigerant leakage. In the multi-type air conditioner, which is connected between the outdoor side provided with a plurality of outdoor units and the indoor side provided with a plurality of indoor units with a high pressure tube and a low pressure tube, When at least one outdoor unit of the plurality of outdoor units is heated and at least one outdoor unit is stopped at the same time, depending on the relationship between the amount of refrigerant flowing into the outdoor unit stopped and the outdoor temperature through the high pressure pipe connected to the outdoor unit for heating operation, A multi-type air conditioner including a leak diagnosis device for determining leakage of refrigerant. The method of claim 7, wherein The driving stop outdoor unit, A compressor, a check valve installed in the refrigerant leakage path, a four-way valve, a bypass circuit for recovering oil to the compressor suction side, and an accumulator connected to the suction side of the compressor, The leak diagnosis apparatus includes a first sensor installed at the suction side of the accumulator connected to the low pressure pipe, a control unit for comparing the output of the first sensor with a reference value set corresponding to the outdoor temperature to determine the leakage of the refrigerant. Multi type air conditioner including. The method of claim 8, The first sensor is a pressure sensor or a temperature sensor multi-type air conditioner. The method of claim 8, The bypass circuit, A multi-type air conditioner for flowing out the refrigerant of the operating outdoor unit introduced through the four-way valve and the check valve to the compressor and the accumulator. In the multi-type air conditioner for controlling the number of operation units of a plurality of outdoor units according to the indoor operating load, Leak diagnosis device for determining the refrigerant leakage of the outdoor unit is stopped of the plurality of outdoor units, The leak diagnosis device, The sensor for detecting the suction pressure or the suction temperature of the accumulator due to the refrigerant flowing into the outdoor unit stopped from the heating operation outdoor unit, the outdoor temperature sensor for detecting the outdoor temperature, and the refrigerant of the outdoor unit stopped according to the output values of the sensors Multi-type air conditioner including a control unit for determining the leakage. Determine whether the heating operation; Sense outdoor temperature; And Determining a refrigerant leakage to the operation stop outdoor unit by comparing the outdoor temperature with a variable value changed according to the refrigerant filled in the accumulator with the refrigerant introduced to the outdoor unit during operation stop; Refrigerant leak diagnosis method of the multi-type air conditioner characterized in that. The method of claim 12, The variable value is a saturation temperature corresponding to the suction pressure of the accumulator, and if the variable value is greater than the value of the first margin plus the outdoor temperature, the refrigerant leakage diagnosis method of the multi-type air conditioner, characterized in that . The method of claim 12, The variable value is the suction temperature of the accumulator, And if the variable value is greater than the value obtained by adding the second margin to the outdoor temperature, the refrigerant leakage diagnosis method of the multi-type air conditioner. In the refrigerant leakage diagnosis method of the multi-type air conditioner in which a high pressure tube and a low pressure tube are connected between an outdoor side provided with a plurality of outdoor units and an indoor side provided with a plurality of indoor units, Determine whether the operation mode is heating operation; When the at least one outdoor unit of the plurality of outdoor units is heated and the at least one outdoor unit is in operation stop, a variable value which varies according to the amount of refrigerant introduced into the accumulator installed on the low pressure side of the stopped outdoor unit is compared with the outdoor temperature; And Determining a refrigerant leak to the operation stop outdoor unit according to the comparison result; Refrigerant leak diagnosis method of the multi-type air conditioner characterized in that. The method of claim 15, Indicating leakage of the refrigerant; Determining whether the leakage time of the refrigerant has elapsed a predetermined time; Forcibly stopping the driving outdoor unit when the leakage time has elapsed; Refrigerant leak diagnosis method of the multi-type air conditioner characterized in that.

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