JP2012007774A - Air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem with a pump-down operation, wherein there is a possibility that hydrofluoroolefin may be decomposed due to a rise of a temperature of a sliding part during the pump-down operation since the hydrofluoroolefin is liable to be decomposed.SOLUTION: An outdoor machine 100 includes: a compressor 1; an outdoor heat exchanger 2; an outdoor blower 3; an expansion valve 4; a two-way valve 5; and a three-way valve 8. An indoor machine 101 includes an indoor heat exchanger 6 and an indoor blower 7. HFO-1234yf is used as an operation coolant. A time of the pump-down operation is shortened by being shifted to pump-down by raising a gas ratio of a coolant which exists in liquid-side connecting piping 21 immediately before the pump-down, the rise of the temperature of the sliding part of the compressor 1 is suppressed, and the decomposition of the coolant is prevented, thus improving reliability.

Description

  The present invention relates to an air conditioner that uses a working refrigerant to form a refrigeration and heat pump cycle for air conditioning, and particularly in an apparatus that forms a cycle by connecting an indoor unit and an outdoor unit with a connecting pipe. When using a working refrigerant with multiple bonds, a technology that can quickly pump down to prevent decomposition of the refrigerant by suppressing a rise in the temperature of the compressor during pump down work to collect the working refrigerant in the outdoor unit. It is to provide.

  In the separation type air conditioner, the refrigerant is usually sealed in the outdoor unit, and after connecting the indoor unit and the outdoor unit with the connection pipe on the liquid side and the gas side, the working refrigerant is opened to the connection pipe and the indoor unit. To install. And in order to transfer the apparatus once installed, when removing an indoor unit, an outdoor unit, and connection piping, the pump down operation | work which collect | recovers refrigerant | coolants to an outdoor unit is performed.

  Conventional pump-down operation is performed by closing the liquid-side on-off valve provided in the outdoor unit and performing cooling operation. When a predetermined time has elapsed, the gas-side on-off valve provided in the outdoor unit is closed and the operation is stopped. (See Patent Document 1).

  At this time, the working refrigerant on the indoor unit side is sucked into the compressor from the gas side connecting pipe, and finally the working refrigerant in the liquid side connecting pipe is sucked into the compressor, thereby completing the pump-down.

  If the pump-down time from the closing of the liquid-side on / off valve to the stoppage of operation is short, the working refrigerant remains on the indoor unit side and is released into the atmosphere when the connection pipe is removed. On the other hand, if the pump down time is too long, the compressor is operated in a state where the working refrigerant does not flow, and the temperature inside the compressor, particularly the sliding portion, rises.

  On the other hand, in recent years, global warming has become a major problem, and the movement to use working refrigerants with low global warming potential has become prominent. Natural refrigerants, hydrofluoroolefins having a double bond between carbon and carbon, etc. The refrigerant is attracting attention.

  Hydrofluoroolefins are particularly attracting attention as alternative refrigerants for R134a, and studies on practical application to automotive air conditioners are being promoted. The warming potential (100 years) is 4 in the case of HFO1234yf, which is extremely small compared to 1300 of R134a and 1730 of R410A used in air conditioners. This characteristic that the warming coefficient is small is attributed to the fact that there is a double bond between carbon and it is easy to decompose.

JP-A-5-157382

  When the pump-down operation of the conventional air conditioner is applied to an air conditioner using hydrofluoroolefin, the working refrigerant may be decomposed due to a temperature rise inside the compressor.

  In a conventional air conditioner, since the working refrigerant is difficult to decompose, the material having the lowest heat resistant temperature in the compressor is a motor insulating film, and the heat resistant temperature is generally about 120 ° C. On the mechanical sliding surface where the temperature is considered to rise the most, no problem occurred even when the temperature reached about 200 ° C.

  However, since hydrofluoroolefin is easy to decompose | disassemble, there exists a possibility of decomposition | disassembly by the temperature rise of a sliding part at the time of pump down operation.

  It is not desirable that the refrigerant, which is a working fluid, decompose itself, and the product at the time of decomposition may adversely affect the metal surface and organic material.

  Therefore, the present invention provides a highly reliable air conditioner by solving such problems and performing a reliable pump down while suppressing a temperature rise inside the compressor.

  In order to solve the above-described conventional problems, an air conditioner according to the present invention is an air conditioner using a refrigerant containing hydrofluoroolefin as a working refrigerant, and the gas ratio of the working refrigerant in the indoor heat exchanger and the connecting pipe is set. After raising, the liquid side shut-off valve is closed and the pump down operation is performed.

  Thereby, the time required for the evaporation of the liquid refrigerant existing in the indoor heat exchanger and the connecting pipe is shortened, the pump-down can be finished quickly, and the temperature rise inside the compressor can be suppressed.

  The air conditioner of the present invention includes a bypass circuit that connects the discharge port of the compression means to the pipe between the outdoor heat exchanger and the liquid side shut-off valve, and a bypass on-off valve provided in the bypass circuit. The operation that opens the bypass on / off valve is performed before the pump down operation.

  As a result, the pump-down can be completed quickly and the temperature rise inside the compressor can be reduced with simple control.

  Moreover, the air conditioner of this invention is provided with the output means which displays that one process was complete | finished, and the input means which inputs that the operator completed one process.

  Thereby, each operation | work can be performed reliably.

  The air conditioner of the present invention can provide a highly reliable device that avoids refrigerant decomposition due to temperature rise when the pump is down.

The block diagram of the air conditioner in Embodiment 1 of this invention The block diagram of the air conditioner in Embodiment 2 of this invention

  The first invention includes a compression means for compressing a working refrigerant, an outdoor heat exchanger, an expansion valve, an outdoor blower, a liquid side shutoff valve, an outdoor unit having a gas side shutoff valve, an indoor heat exchanger, and an indoor fan having an indoor blower Is an air conditioner that constitutes a refrigeration cycle or a heat pump cycle using a working refrigerant containing hydrofluoroolefin as a working refrigerant, and is connected to the indoor heat exchanger and the connecting pipe. After increasing the gas ratio of the working refrigerant, the liquid-side closing valve is closed and the cooling operation is performed for a predetermined time, and then the gas-side closing valve is closed and the pump-down operation for collecting the working refrigerant in the outdoor unit is performed.

  As a result, the time required for the evaporation of the liquid refrigerant is shortened, and the pump-down can be completed quickly, and the temperature rise inside the compressor can be suppressed.

  Therefore, decomposition of the hydrofluoroolefin contained in the working refrigerant can be prevented and a highly reliable device can be provided.

  According to a second invention, in the first invention, the cooling operation is performed for a predetermined time before the pump-down operation is performed, and then the opening of the expansion valve is opened for a predetermined time as compared with the cooling operation. The pump down operation is performed.

  As a result, the working refrigerant temperature at the outlet of the outdoor heat exchanger rises and the working refrigerant cannot be supercooled, and the specific enthalpy increases. Therefore, downstream of the expansion valve, that is, the liquid side connection pipe, the indoor heat exchanger, the gas side connection pipe The gas ratio of the working refrigerant increases.

  According to a third invention, in the first invention, after performing the cooling operation for a predetermined time before performing the pump-down operation, and subsequently operating the pump for a predetermined time by reducing the blast volume of the outdoor blower compared to the cooling operation, Down operation is performed.

  As a result, the amount of heat released in the outdoor heat exchanger is reduced, the working refrigerant temperature at the outlet of the outdoor heat exchanger is increased, and the working refrigerant in the downstream of the expansion valve, that is, in the liquid side connection pipe, the indoor heat exchanger, and the gas side connection pipe The gas ratio increases.

  Therefore, the time required for the evaporation of the liquid refrigerant is shortened, and the pump-down can be completed quickly, and the temperature rise inside the compressor can be suppressed.

  4th invention increases the ventilation volume of an outdoor air blower after closing a liquid side closing valve at the time of pump down driving | operation in 3rd invention.

  Thereby, in the pump down operation, the recovered working refrigerant can be condensed and accumulated in the outdoor heat exchanger, and evaporation of the working refrigerant staying in the indoor heat exchanger can be promoted.

  Therefore, the time required for the evaporation of the liquid refrigerant is shortened, the pump down is completed, and the temperature rise inside the compressor can be suppressed.

  According to a fifth invention, in the first invention, a bypass circuit that connects the discharge port of the compression means to a pipe between the outdoor heat exchanger and the liquid-side closing valve, and a bypass opening / closing valve provided in the bypass circuit And performing an operation in which the bypass on-off valve is opened before the pump down operation is performed.

  Thereby, since the high-temperature gas refrigerant is sent from the compressor to the liquid side connection pipe and the indoor heat exchanger, the working refrigerant gas existing in the liquid side connection pipe, the indoor heat exchanger, and the gas side connection pipe The ratio can be increased.

  Accordingly, the simple control of opening / closing the bypass opening / closing valve can quickly terminate the pump down and suppress the temperature rise inside the compressor.

  6th invention is provided with the output means which displays that one process was completed, and the input means which inputs that a worker completed one process in any invention of the 1st-5th It is.

  As a result, the worker can know that one process has been completed, and can reliably perform the work while checking each work. Therefore, mistakes in the pump down operation can be reduced.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 shows a configuration diagram of an air conditioner according to a first embodiment of the present invention.

  As shown in FIG. 1, the air conditioner in 1st Embodiment connects the outdoor unit 100 and the indoor unit 101 with the liquid side connection piping 21 and the gas side connection piping 22 which are connection piping, and is apparatus. It is composed.

  The outdoor unit 100 includes a compressor 1, which is a compression means, an outdoor heat exchanger 2, an outdoor blower 3, an expansion valve 4 for decompressing and expanding the working refrigerant, a two-way valve 5 which is a liquid side closing valve, and a gas side closing valve. A certain three-way valve 8 is provided. The indoor unit 101 includes an indoor heat exchanger 6 and an indoor blower 7. The compressor 1, the outdoor heat exchanger 2, the expansion valve 4, the two-way valve 5, the liquid side connection pipe 21, the indoor heat exchanger 6, the gas side connection pipe 22, and the three-way valve 8 are connected by piping and operated. A refrigerant circuit through which the refrigerant flows is configured. As the working refrigerant, HFO-1234yf, which is a hydrofluoroolefin having a double bond between carbons and having a small warming potential, is used.

  The air conditioner also includes a work instruction lamp 9 which is an output means for displaying that one process of pumping down is completed, and a work which is an input means for inputting that a worker has completed one process. A completion button 10 is provided. The work instruction lamp 9 and the work completion button 10 are provided on, for example, an outdoor unit control board constituting a control device of the air conditioner or a remote controller that communicates with the control device.

  The normal operation of the air conditioner configured as described above will be described. The working refrigerant that has returned from the indoor unit 101 to the outdoor unit 100 is sucked into the compressor 1 through the three-way valve 8 and compressed, and is sent to the outdoor heat exchanger 2 as a high-temperature and high-pressure refrigerant. Cooled and condensed by the air sent, depressurized by the expansion valve 4, sent to the indoor unit 101 through the two-way valve 5, and deprived of heat from the air sent by the indoor blower 7 in the indoor heat exchanger 6. It evaporates and returns to the outdoor unit 100 again. By taking heat from the air sent by the indoor blower 7 in the indoor heat exchanger 6, the air in the space where the indoor unit 101 is installed is cooled, that is, cooled.

  Next, the time of installation and relocation of such an air conditioner will be described.

  In the case of the separation type air conditioner as shown in FIG. 1, the refrigerant is sealed in the outdoor unit 100 before installation. At the time of installation, the indoor unit 101 and the outdoor unit 100 are connected by the liquid side connection pipe 21 and the gas side connection pipe 22. Thereafter, with the two-way valve 5 closed, the service port of the three-way valve 8 and the vacuum pump are connected by a hose. Then, the vacuum pump is operated to vacuum the air in the indoor unit 101 side piping (the piping from the two-way valve 5 to the three-way valve 8 and including the indoor heat exchanger 6) from the service port of the three-way valve 8. Pull. Thereafter, the two-way valve 5 and the three-way valve 8 are opened to release the refrigerant into the pipe, thereby completing the installation.

  Further, when the installed air conditioner is moved, the working refrigerant is again collected in the outdoor unit 100 and moved by removing the liquid side connection pipe 21 and the gas side connection pipe 22. Such an operation of collecting the working refrigerant again in the outdoor unit 100 is referred to as pump down.

  In the conventional pump-down operation, after performing a cooling operation for a predetermined time as a preliminary operation, the two-way valve 5 is closed, the cooling operation is continued for about 3 minutes, and the three-way valve 8 is closed to stop the operation. At this time, when a pressure measuring means such as a gauge manifold is connected to the service port of the three-way valve 8 and pumping down is performed, the two-way valve 5 is closed until the pressure measuring means displays negative pressure. Cooling operation is performed.

  At this time, if the pump down is not sufficient, the working refrigerant remains in the connection pipe and the pipe on the indoor unit 101 side. As a result, if the connection pipe is removed as it is, the working refrigerant is released into the atmosphere. Although the global warming potential is small, it is not desirable that the fluorine compound is released into the atmosphere, and it is desirable to collect the working refrigerant as much as possible from the viewpoint of reducing the working refrigerant in the apparatus. However, if the operation in which the two-way valve 5 is closed, that is, the pump-down operation is continued for a long time, the operation in a state where the working refrigerant does not circulate continues. The temperature of the sliding part of the machine 1 rises.

  Here, in the air conditioner of the present embodiment, HFO-1234yf is used as a working refrigerant. However, since this refrigerant has a double bond between carbons, it is easily decomposed and oxygen is present. If the temperature rises, it will easily decompose and produce acid and various organic substances, metal parts such as the sliding parts and piping of the compressor 1, motor windings of the compressor 1, etc. There is a possibility of damaging the organic material in each valve part.

  Further, even when oxygen is not present, the refrigerant is decomposed at the high temperature portion. The material having the lowest heat resistant temperature in the compressor 1 is an insulating film of a motor, and the heat resistant temperature is generally about 120 ° C. The mechanical sliding surface that is considered to have the highest temperature reaches a temperature of about 200 ° C. Conventionally, since the refrigerant was difficult to decompose, no problem occurred. However, in the apparatus using HFO-1234yf as the refrigerant, it is easy to decompose, and therefore the working refrigerant is increased due to the temperature rise of the sliding portion during the pump down operation. May break down.

  Therefore, the air conditioner of Embodiment 1 of the present invention shortens the time of the pump-down operation as follows, suppresses the temperature rise of the sliding portion of the compressor 1, and prevents the working refrigerant from being decomposed and is reliable. It is intended to improve the performance.

  First, the basic idea is that the gas ratio of the working refrigerant existing in the liquid side connection pipe 21, the indoor heat exchanger 6, and the gas side connection pipe 22 (gas refrigerant, liquid refrigerant and gas refrigerant before the pump down operation). The weight or volume ratio with respect to the sum of the above is increased as much as possible to shift to the pump-down operation. In particular, it is desirable to increase the gas ratio of the working refrigerant present in the liquid side connection pipe 21.

  The reason for this will be described below. Since the liquid side connection pipe 21 is covered with a heat insulating material, the liquid refrigerant inside the liquid side connection pipe 21 is not easily evaporated by heat absorption. For this reason, the working refrigerant present inside the liquid side connection pipe 21 is in a state where the dryness is the lowest on the low pressure side. On the other hand, in the indoor heat exchanger 6, even if there is a liquid refrigerant, heat is exchanged with the air and it is quickly evaporated. Further, since the gas side connection pipe 22 is also covered with the heat insulating material, it is not possible to expect rapid evaporation of the working refrigerant, but since it is carried to the compressor 1 together with the working refrigerant evaporated in the indoor heat exchanger 6, Is recovered by the compressor 1.

  The liquid refrigerant is likely to stay during the pump-down operation, and when the liquid pool is generated, the refrigerant in that portion is evaporated and then collected by the compressor 1, so it is necessary to absorb heat from the surroundings. When a part of the liquid refrigerant evaporates with the heat of evaporation from the surroundings, the ambient temperature decreases accordingly. As the evaporation and temperature decrease are repeated, the ambient temperature of the liquid refrigerant decreases, and the liquid refrigerant becomes more difficult to evaporate and it takes time to recover the refrigerant.

  On the other hand, when the amount of liquid refrigerant is small, the ambient temperature is kept at a relatively high temperature, and the liquid refrigerant is kept in a state where it is easily evaporated. As a result, the working refrigerant can be quickly recovered, the temperature rise of the sliding portion of the compressor 1 can be suppressed, and the refrigerant can be prevented from being decomposed to improve the reliability.

  A specific method for increasing the gas ratio of the liquid side connection pipe 21, the indoor heat exchanger 6, and the gas side connection pipe 22 is as follows.

  In the first method, the cooling operation is performed for a predetermined time before the pump-down operation is performed, and the pump-down operation is subsequently performed after the opening of the expansion valve 4 is opened for a predetermined time as compared with the cooling operation. That is.

  When the opening degree of the expansion valve 4 is opened, the pressure of the working refrigerant having a high pressure at the outlet of the outdoor heat exchanger 2 is slightly lowered, and the temperature of the working refrigerant at the outlet of the outdoor heat exchanger 2 is raised. For this reason, the specific enthalpy of the working refrigerant at the outlet of the outdoor heat exchanger 2 increases, and supercooling cannot be obtained, and the dryness of the outlet of the expansion valve 4 increases. As a result, the gas ratio of the liquid side connection pipe 21, the indoor heat exchanger 6, and the gas side connection pipe 22 increases.

  As a second method, there is a method of reducing the amount of air blown by the outdoor blower 3. When the amount of air blown from the outdoor blower 3 is reduced, the amount of heat released from the outdoor heat exchanger 2 is reduced, the refrigerant pressure and temperature at the outlet of the outdoor heat exchanger 2 are increased, and the specific enthalpy is increased. For this reason, the dryness of the outlet of the expansion valve 4 increases, and the gas ratio of the liquid side connection pipe 21, the indoor heat exchanger 6, and the gas side connection pipe 22 increases.

  When carrying out the second method, it is desirable to increase the amount of air blown by the outdoor blower 3 when the pump down operation is started. Thereby, the amount of heat radiation in the outdoor heat exchanger 2 can be increased, the recovered refrigerant can be condensed and stored easily, and the pump can be pumped down safely and promptly.

  The specific methods for increasing the gas ratio of the liquid side connection pipe 21 described above are effective in each case and are effective even when used together, and can be implemented by changing the control with the conventional configuration. Is. That is, the air conditioner of the present embodiment can achieve the avoidance of the decomposition of the working refrigerant due to the temperature rise at the time of pump down by simple control.

  Next, operations and usage methods of the work instruction lamp 9 and the work completion button 10 will be described.

  When pumping down is performed, the worker first presses the work completion button 10 and inputs the start of the work. Then, a control device (not shown) starts the cooling operation of the air conditioner. And the process of performing the concrete method which raises the gas ratio of the liquid side connection piping 21, the indoor heat exchanger 6, and the gas side connection piping 22 is implemented, and when the process is completed, the work instruction lamp 9 is flashed once. . The worker who has confirmed this closes the two-way valve 5 and presses the work completion button 10 again to start the pump-down operation. Then, the control device starts the pump-down operation, and when the predetermined time has passed, the air conditioner repeats blinking of the work instruction lamp 9 twice to notify the end of the pump-down operation process. When the worker who has confirmed this closes the three-way valve 8 and presses the work completion button 10, the air conditioner stops operation. This completes the pump down.

  That is, the air conditioner according to the present embodiment can reliably perform each process by the work instruction lamp 9 and the work completion button 10 and reduce work mistakes.

  In the present embodiment, the operation of the two-way valve 5 and the three-way valve 8 is performed by an operator, and the completion of these operations is input by pressing the work completion button 10, but the two-way valve 5 Further, the operation completion button 10 can be eliminated by automatically operating the three-way valve 8 by the control device. In this case, it goes without saying that work errors can be further reduced.

(Embodiment 2)
FIG. 2 shows a configuration diagram of an air conditioner according to the second embodiment of the present invention.

  As shown in FIG. 2, the air conditioner of FIG. 1 includes a bypass circuit 11 that leads from the discharge of the compressor 1 to a pipe between the expansion valve 4 and the two-way valve 5, and the bypass circuit 11 includes a bypass on-off valve. 12 is additionally provided.

  The pump-down procedure of this embodiment will be described.

  First, a normal cooling operation is performed for a predetermined time as a preliminary operation. Of course, at this time, the bypass on-off valve 12 is closed. After performing the cooling operation for a predetermined time, the bypass on-off valve 12 is continuously opened for operation. A part of the high-temperature and high-pressure working refrigerant discharged from the compressor 1 dissipates heat and condenses in the outdoor heat exchanger 2, and the other flows from the outdoor heat exchanger 2 at the junction after flowing through the bypass circuit 11. The refrigerant that has flowed joins, passes through the two-way valve 5, and flows from the liquid side connection pipe 21 to the indoor unit 101.

  According to this, since the high-temperature and high-pressure refrigerant immediately discharged from the compressor 1 flows through the bypass circuit 11, the refrigerant having a higher dryness flows in the liquid side connection pipe 21 than in the normal cooling operation. . Therefore, it is difficult to evaporate due to heat absorption, and the working refrigerant in the liquid side connection pipe 21 that is in the lowest dryness state on the low pressure side can be quickly evaporated and recovered in the compressor 1.

  Thereafter, the two-way valve 5 is closed and the operation is continued for a predetermined time, and the three-way valve 8 is closed to end the pump-down operation. Although the air conditioner of FIG. 2 has more components, the control when the pump is down is extremely simple, and it is difficult to cause malfunctions and work errors.

  Next, operations and usage methods of the work instruction lamp 9 and the work completion button 10 will be described.

  When pumping down is performed, the worker first presses the work completion button 10 and inputs the start of the work. Then, the control device starts a normal cooling operation. When a predetermined time has elapsed, the work instruction lamp 9 repeats blinking once. The worker who has confirmed this opens the bypass opening / closing valve 12 and presses the work completion button 10 again. Further, when the predetermined time has elapsed, the work instruction lamp 9 repeats blinking twice. The worker who has confirmed this closes the two-way valve 5 and presses the work completion button 10 again to start the pump-down operation. Then, the control device starts the pump-down operation, and when the predetermined time has passed, the air conditioner repeatedly flashes the work instruction lamp 9 three times to notify the end of the pump-down operation process. When the worker who has confirmed this closes the three-way valve 8 and presses the work completion button 10, the air conditioner stops operation. This completes the pump down.

  That is, the air conditioner according to the present embodiment can reliably perform each process by the work instruction lamp 9 and the work completion button 10 and reduce work mistakes.

  In the present embodiment, the operation of the bypass on-off valve 12 is performed by an operator, and the completion of those operations is input by pressing the work completion button 10, but the operation of the bypass on-off valve 12 is also controlled. The operation completion button 10 can be abolished by the automatic operation of the apparatus. In this case, it goes without saying that work errors can be further reduced.

  In addition, although the air conditioner in the above embodiment is a cooling only machine which cannot perform heating operation, it can equip with the four-way valve which switches the flow direction of a working refrigerant at the exit of the compressor 1, and can perform heating operation. The same effect can be obtained even in cool and warm models.

  Moreover, although HFO-1234yf was used as the refrigerant, even if it is HFO-1234ze or a mixed refrigerant containing HFO-1234yf or HFO-1234ze, the same effect can be obtained. An example of such a mixed refrigerant is a mixed refrigerant of HFO-1234yf and HFC-32.

  As described above, when performing the pump-down operation, the air conditioner according to the present invention increases the gas ratio of the working refrigerant present in the liquid-side connection pipe, and then closes the liquid-side shut-off valve and pumps down. It is for driving. As a result, the pump-down can be quickly finished, and the temperature rise inside the compressor can be suppressed.

  As a result, a refrigerant that is easily decomposed, such as a hydrofluoroolefin having a double bond between carbon and carbon, can be used, and the environment is excellent.

  Further, the present invention is not limited to the air conditioner, and can be widely applied to a separate type showcase, a refrigerator, a heat pump type water heater, and the like, and brings about an effect.

DESCRIPTION OF SYMBOLS 1 Compressor 2 Outdoor heat exchanger 3 Outdoor blower 4 Expansion valve 5 Two-way valve 6 Indoor heat exchanger 7 Indoor blower 8 Three-way valve 9 Work instruction lamp 10 Work completion button 11 Bypass circuit 12 Bypass on-off valve 21 Liquid side connection piping 22 Gas side connection piping 100 Outdoor unit 101 Indoor unit

Claims (6)

Compressing means for compressing working refrigerant, outdoor heat exchanger, expansion valve, outdoor blower, liquid side shutoff valve, outdoor unit having gas side shutoff valve, indoor heat exchanger, indoor unit having indoor blower, connecting piping And an air conditioner constituting a refrigeration cycle or a heat pump cycle using a refrigerant containing hydrofluoroolefin as the working refrigerant, wherein the working refrigerant in the indoor heat exchanger and the connecting pipe After increasing the gas ratio, the liquid side closing valve is closed and the cooling operation is performed for a predetermined time, and then the gas side closing valve is closed and the pump down operation for collecting the working refrigerant in the outdoor unit is performed. Air conditioner. A cooling operation is performed for a predetermined time before performing the pump-down operation, and then the pump-down operation is performed after opening for a predetermined time by opening the opening of the expansion valve as compared with the cooling operation. The air conditioner according to claim 1. A cooling operation is performed for a predetermined time before the pump-down operation is performed, and then the pump-down operation is performed after the operation is performed for a predetermined time by reducing the amount of air blown from the outdoor fan compared to the cooling operation. The air conditioner according to claim 1. 4. The air conditioner according to claim 3, wherein, during the pump-down operation, after the liquid side shut-off valve is closed, the amount of air blown from the outdoor blower is increased. A bypass circuit connecting the discharge port of the compression means to a pipe between the outdoor heat exchanger and the liquid side shut-off valve, and a bypass on-off valve provided in the bypass circuit, and the pump down operation 2. The air conditioner according to claim 1, wherein the operation is performed with the bypass on-off valve opened before the operation. The output means for displaying that one process has been completed and the input means for inputting that the worker has completed one process are provided. Air conditioner.

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