Patent Publication Number: US-2022214061-A1

Title: Air conditioner

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application is a continuation application of International Application No. PCT/JP2020/034252, filed on Sep. 10, 2020. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to air conditioners. 
     BACKGROUND ART 
     There is known an air conditioner in which a drain pan where drain water is stored is irradiated with deep ultraviolet rays having a relatively short wavelength among the ultraviolet rays (see, for example, Japanese Laid-Open Patent Publication No. 2017-133700). The irradiation with deep ultraviolet rays causes denaturation or inactivation of bacteria, mold, or the like contained in the drain water (hereinafter, referred to as “sterilization”). 
     SUMMARY 
     Patent Literature 1 discloses that an irradiating operation is performed in relation to a cooling operation, but does not disclose how to control when a stop operation to stop the irradiating operation is performed during the irradiating operation. When the stop operation is performed when sterilization has not been completed yet, bacteria, mold, or the like remaining due to non-completion of sterilization easily propagates in drain water. In such a state, it is difficult to keep the inside of an indoor unit clean. 
     The present disclosure provides an air conditioner capable of keeping the inside of an indoor unit clean. 
     An air conditioner according to an aspect of the present disclosure includes: a control unit configured to control an air conditioning operation and control a maintenance operation to perform maintenance on an indoor unit of the air conditioner after the air conditioning operation is stopped; and an operation unit provided for performing a stop operation to stop the maintenance operation. The maintenance operation includes an irradiating operation to irradiate an irradiation area of the indoor unit with ultraviolet rays, and the control unit controls the irradiating operation to continue the irradiating operation even when the stop operation is performed by the operation unit. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a diagram illustrating a refrigerant circuit of an air conditioner according to an embodiment. 
         FIG. 2  is a control block diagram of the air conditioner illustrated in  FIG. 1 . 
         FIG. 3  is a schematic cross-sectional view of an indoor unit that is out of operation, the indoor unit being a component of the air conditioner illustrated in  FIG. 1 . 
         FIG. 4  is a diagram illustrating a state where a panel of a remote control is closed. 
         FIG. 5  is a diagram illustrating a state where the panel of the remote control is opened. 
         FIG. 6  is a timing chart of a maintenance operation of the air conditioner. 
         FIG. 7  is a control flowchart of the maintenance operation of the air conditioner. 
     
    
    
     DESCRIPTION OF EMBODIMENT 
     Hereinafter, an air conditioner according to an embodiment of the present disclosure will be described with reference to the drawings. Note that the same parts in the drawings are denoted by the same reference sign, and no redundant description will be given. 
     [Overall Configuration of Air Conditioner  1 ] 
       FIG. 1  is a diagram illustrating a refrigerant circuit of an air conditioner  1  according to the embodiment of the present disclosure. As illustrated in  FIG. 1 , the air conditioner  1  includes an indoor unit  2  installed indoors and an outdoor unit  3  installed outdoors, the indoor unit  2  and the outdoor unit  3  being connected with each other via connection pipes L 1 , L 2 . The air conditioner  1  is of a type in which the indoor unit  2  is paired one-to-one with the outdoor unit  3 . 
     The indoor unit  2  is equipped with an indoor heat exchanger  4  and an indoor fan  5 . The outdoor unit  3  is equipped with a compressor  6 , a four-way switching valve  7 , an outdoor heat exchanger  8 , an outdoor fan  9 , an electric expansion valve (hereinafter, referred to as an expansion valve)  10  as an example of the decompressing mechanism, and an accumulator  11 . The outdoor unit  3  is further provided with a liquid-side shutoff valve  12  and a gas-side shutoff valve  13 . 
     The compressor  6 , the four-way switching valve  7 , the outdoor heat exchanger  8 , the expansion valve  10 , the indoor heat exchanger  4 , the accumulator  11 , and the compressor  6  are connected in this order via a refrigerant pipe and the connection pipes L 1 , L 2  to form a refrigerant circuit. The liquid-side shutoff valve  12  is interposed between the expansion valve  10  and the connection pipe L 1 , and the gas-side shutoff valve  13  is interposed between the four-way switching valve  7  and the connection pipe L 2 . 
     In the refrigerant circuit, the compressor  6  has a discharge port connected to the outdoor heat exchanger  8  via the four-way switching valve  7  and has an intake port connected to the indoor heat exchanger  4  via the four-way switching valve  7  and the accumulator  11 . 
     A remote controller  17  (hereinafter, referred to as a “remote control  17 ”) can bring the air conditioner  1  configured as described above into cooling operation, dehumidifying operation, and heating operation (hereinafter, collectively referred to as a “normal operation”). The remote control  17  can switch, start, or stop various operations, set an indoor temperature, set a rotational speed of the indoor fan  5 , and the like. The air conditioner  1  configured as described above allows the remote control  17  to enable to set a maintenance operation for keeping internal members built in the indoor unit  2  clean. 
     During the cooling operation and the dehumidifying operation, a cooling cycle is established as indicated by solid arrows in which a refrigerant discharged from the compressor  6  sequentially flows from the four-way switching valve  7  to the indoor heat exchanger  4  through the outdoor heat exchanger  8  and the expansion valve  10  and returns to the compressor  6  through the four-way switching valve  7  and the accumulator  11 . That is, the outdoor heat exchanger  8  functions as a condenser, and the indoor heat exchanger  4  functions as an evaporator. Note that, during the dehumidifying operation, although the indoor fan  5  is driven to an extent less than during the cooling operation, the refrigerant passing through the indoor heat exchanger  4  evaporates as a result of exchanging heat with indoor air. This causes moisture in the air to be condensed and collected on a surface of the indoor heat exchanger  4 , thereby dehumidifying the air inside the room. Therefore, an operation during which condensed water is generated on the surface of the indoor heat exchanger  4  such as the cooling operation and the dehumidifying operation is herein referred to as a cooling operation. 
     On the other hand, during the heating operation, a heating cycle is established as indicated by dashed arrows in which the four-way switching valve  7  is switched to cause the refrigerant discharged from the compressor  6  to sequentially flow from the four-way switching valve  7  to the outdoor heat exchanger  8  through the indoor heat exchanger  4  and the expansion valve  10  and return to the compressor  6  through the four-way switching valve  7  and the accumulator  11 . That is, the indoor heat exchanger  4  functions as a condenser, and the outdoor heat exchanger  8  functions as an evaporator. 
     As illustrated in  FIG. 1 , the indoor unit  2  is equipped with an indoor-unit controller (control unit)  14  that controls various operations of the indoor unit  2 , and the outdoor unit  3  is equipped with an outdoor-unit controller (control unit)  15  that controls various operations of the outdoor unit  3 . The air conditioner  1  is controlled as a whole by the indoor-unit controller (control unit)  14  or the outdoor-unit controller (control unit)  15 , or under cooperation between the indoor-unit controller (control unit)  14  and the outdoor-unit controller (control unit)  15 . Therefore, at least either the indoor-unit controller  14  or the outdoor-unit controller  15  acts as a control unit  16  that controls various operations of the air conditioner  1 . 
     As illustrated in  FIG. 2 , the compressor  6 , the four-way switching valve  7 , the expansion valve  10 , the indoor fan  5 , and the outdoor fan  9  are connected to the control unit  16 . Specifically, various drive units (e.g., a motor and a solenoid) for driving such components are connected to the control unit  16 . An outdoor heat exchanger temperature sensor T 1 , an outdoor air temperature sensor T 2 , an indoor heat exchanger temperature sensor T 3 , and an indoor temperature sensor T 4  are connected to the control unit  16 . An irradiation unit  40  is connected to the control unit  16 . Further, a filter cleaner  43  and a notification unit  45  are connected to the control unit  16 . 
     The outdoor heat exchanger temperature sensor T 1  is installed in the outdoor heat exchanger  8  to detect a temperature of the outdoor heat exchanger  8 . The outdoor air temperature sensor T 2  is installed in the outdoor unit  3  to detect an outdoor temperature. The indoor heat exchanger temperature sensor T 3  is installed in the indoor heat exchanger  4  to detect a temperature of the indoor heat exchanger  4 . The indoor temperature sensor T 4  is installed in the indoor unit  2  to detect an indoor temperature. 
     The control unit  16  includes a microcomputer, an input-output circuit, and the like. The control unit  16  controls the operation of the air conditioner  1  by performing operation processing, determination processing, or the like based on a command (such as an operation start command or an indoor temperature setting command) sent from the remote control  17  or various temperatures detected by the outdoor heat exchanger temperature sensor T 1 , the outdoor air temperature sensor T 2 , the indoor heat exchanger temperature sensor T 3 , and the indoor temperature sensor T 4 . 
     [Configuration of Indoor Unit] 
       FIG. 3  is a schematic cross-sectional view of the indoor unit  2  that is out of operation, the indoor unit  2  being a component of the air conditioner  1 . The indoor unit  2  illustrated in  FIG. 3  is of a wall-mounted type. 
     The indoor unit  2  includes a casing  30  including a casing body  31  and a front panel  32 . The casing  30  is attached to a wall surface W facing an indoor space and accommodates the indoor fan  5 , the indoor heat exchanger  4 , the drain pan  33 , and the like. 
     The casing body  31  includes a plurality of parts: a front part  31   a , an upper part  31   b , a rear part  31   c , and a lower part  31   d . The front panel  32  is attached to the front part  31   a  in an openable and closable manner. Further, an intake port (not illustrated) is provided extending from the front part  31   a  to the upper part  31   b.    
     The front panel  32  is associated with the front part  31   a  of the indoor unit  2  and has, for example, a flat shape with no intake port. Further, an upper end of the front panel  32  is pivotably supported by the upper part  31   b  of the casing body  31  and thus can swing in a hinged manner. 
     The indoor fan  5  and the indoor heat exchanger  4  are attached to the casing body  31 . The indoor heat exchanger  4  exchanges heat with indoor air drawn into the casing  30  through the intake port. Further, the indoor heat exchanger  4  has an inverted V shape in a side view with both ends extending downward and a bend positioned higher. The indoor heat exchanger  4  includes a plurality of heat transfer tubes and a large number of fins. 
     The indoor fan  5  is positioned below the bend of the indoor heat exchanger  4 . The indoor fan  5  is, for example, a cross-flow fan. The indoor fan  5  forces indoor air passing through the indoor heat exchanger  4  to flow to a blow-out port  34  of the lower part  31   d  of the casing body  31 . 
     The casing body  31  is further provided with a first partition wall  35  and a second partition wall  36 . A space between the first partition wall  35  and the second partition wall  36  serves as a blow-out flow path  37  through which the indoor fan  5  and the blow-out port  34  communicate with each other. 
     The drain pan  33  is disposed below the indoor heat exchanger  4  and receives condensed water generated by condensation on the indoor heat exchanger  4 . The drain pan  33  includes an upper receiver  33   a , a lower receiver  33   b , and a connecting part (not illustrated) through which the upper receiver  33   a  and the lower receiver  33   b  are connected with each other. The condensed water drops from the indoor heat exchanger  4  into both the upper receiver  33   a  and the lower receiver  33   b . The condensed water dropped into the upper receiver  33   a  flows down to the lower receiver  33   b  through the connecting portion. The condensed water flowing down from the upper receiver  33   a  to the lower receiver  33   b  and the condensed water dropped into the lower receiver  33   b  accumulate in the lower receiver  33   b  as drain water. The drain water accumulated in the lower receiver  33   b  is drained, by its own weight, outside from a drain port  38  provided in the lower receiver  33   b  through a drain hose  39 . That is, the drain pan  33  is structured to cause the drain water to flow out by its own weight. 
     The control unit  16  controls the cooling operation to make the temperature of the indoor heat exchanger  4  measured by the indoor heat exchanger temperature sensor T 3  lower than the dew point, thereby generating drain water. The control unit  16  can estimate a water level of the drain water accumulated in the lower receiver  33   b  of the drain pan  33  based on the operation status of the cooling operation. Therefore, the control unit  16  functions as a detection unit that detects the water level of the drain water accumulated in the drain pan  33 . Some air conditioners, e.g., air conditioners installed at high places such as ceiling-embedded air conditioners and ceiling-suspended air conditioners, may have a water level sensor installed as a detection unit that detects the water level of the drain water accumulated in the drain pan  33 . 
     The irradiation unit  40  (illustrated in  FIG. 2  but not illustrated in  FIG. 3 ) is provided above the drain pan  33 . The irradiation unit  40  emits deep ultraviolet rays (hereinafter, referred to as “ultraviolet rays”) having a relatively short wavelength among ultraviolet rays to irradiate an upper surface of the drain pan  33  with the ultraviolet rays. The irradiation unit  40  is, for example, an ultraviolet LED (light emitting diode). The ultraviolet rays emitted by the irradiation unit  40  have a wavelength of, for example, 255 nm to 350 nm. 
     In order to denature or inactivate bacteria, mold, or the like contained in the drain water, i.e., to perform sterilization, it is necessary to emit the ultraviolet rays by a predetermined dose. The dose of the ultraviolet rays to be emitted is determined by multiplying the ultraviolet intensity by the irradiation time, that is, by the ultraviolet intensity*the irradiation time. The control unit  16  controls the ultraviolet intensity and the irradiation time of the irradiation unit  40  so as to obtain the predetermined dose necessary for sterilization. 
     The irradiation unit  40  irradiates an irradiation area, i.e., an area to-be-irradiated such as the drain pan  33  with ultraviolet rays, by the predetermined dose to sterilize the to-be-irradiated area, thereby allowing the inside of the indoor unit  2  to be kept clean. 
     The indoor unit  2  includes a first horizontal flap  41  and a second horizontal flap  51  disposed behind the first horizontal flap  41  (adjacent to the wall surface W). The first horizontal flap  41  and the second horizontal flap  51  adjust a vertical direction of air blowing out from the blow-out port  34  (air flowing through the blow-out flow path  37 ). The first horizontal flap  41  is pivotably attached to the lower part  31   d  of the casing body  31 . In the state illustrated in  FIG. 3 , the indoor fan  5  is stopped, the front panel  32 , the first horizontal flap  41 , and the second horizontal flap  51  are closed, and the air conditioning operation by the indoor unit  2  is stopped. Note that the first horizontal flap  41  is an example of a first horizontal blade. Further, the second horizontal flap  51  is an example of a second horizontal blade. 
     The indoor unit  2  further includes a plurality of vertical flaps (not illustrated) that adjust a lateral direction of air blowing out. The plurality of vertical flaps are arranged in the blow-out flow path  37  at predetermined intervals in a longitudinal direction of the blow-out port  34  (a direction perpendicular to the drawing sheet of  FIG. 3 ). Note that the vertical flap is an example of a perpendicular blade. 
     The indoor unit  2  is equipped with a filter  47  and the filter cleaner  43 . The filter  47  is disposed to cover almost all over a frontside (air flow upstream side) of the indoor heat exchanger  4  so as to remove dust contained in the air flowing toward the indoor heat exchanger  4 . The filter cleaner  43  is provided to clean the filter  47  to remove dust adhering to the filter  47 . The filter cleaner  43  includes, for example, a rotary brush, a brush motor, a dust box, and a filter transfer means (none of which are illustrated). The dust removed from the filter  47  is accumulated in the dust box. Further, the dust box is detachably attached to the casing  30 . 
     Further, the control unit  16  brings the rotary brush, the filter transfer means, and the like of the filter cleaner  43  into operation to control a filter cleaning operation. The filter cleaning operation thus performed can remove dust from the filter  47  accommodated in the casing  30 . 
     The indoor unit  2  is further equipped with the notification unit  45 . The notification unit  45  is a display device (for example, an LED or liquid crystal display device) or a speaker. The control unit  16  controls the display device to output a message about operation in a visual form. The control unit  16  controls the speaker to output the message about operation in an audio form. 
     For example, as will be described later, even when the user presses an “ON/OFF” button  66  of the remote control  17  to stop the irradiating operation, the irradiating operation is controlled to continue. At this time, the notification unit  45  notifies the user of the continuation of the irradiating operation in either the visual form or the audio form. The notification unit  45  can make the user aware of the continuation of the irradiating operation even when the user intends to stop the irradiating operation. 
     [Remote Control] 
     The remote control  17  is a device provided for remotely controlling the air conditioner  1 , and includes, as illustrated in  FIGS. 4 and 5 , a remote control casing  61 , operation buttons, a display unit  64 , and a remote control side control unit (not illustrated). 
     The remote control casing  61  has a substantially rectangular parallelepiped shape, and accommodates the remote control side control unit and the like. Further, as illustrated in  FIG. 5 , the remote control casing  61  includes a panel  62 . The panel  62  is attached in an openable and closable manner to cover a front surface  63  of the remote control casing  61 . Specifically, the panel  62  covers the front surface  63  of the remote control casing  61  when closed, and exposes the front surface  63  of the remote control casing  61  to the outside when opened. 
     The operation buttons are provided on the front surface  63  and the panel  62  of the remote control casing  61 . As illustrated in  FIG. 4 , the panel  62  is provided with operation buttons such as the “ON/OFF” button  66 , a “temperature” button, a “humidity” button, and a “setting confirmation” button. The “ON/OFF” button  66  receives, from the user, a request for the start or stop of the normal operation and a second maintenance operation of the air conditioner  1 . As described later, the second maintenance operation is an operation obtained by removing an ultraviolet rays irradiating operation serving as a first maintenance operation from the maintenance operation, and includes, for example, the filter cleaning operation and an internal cleaning operation. 
     As illustrated in  FIG. 5 , various operation buttons such as a “menu” button  67 , an “enter” button  68 , and an “up” or “down” button are provided on the front surface  63  of the remote control casing  61 . The “menu” button  67  and the “enter” button  68  are buttons to be operated by the user when the user changes an operating mode or function setting. 
     The “menu” button  67  acts as a forced operation unit to forcibly stop the ultraviolet rays irradiating operation. The “menu” button  67  is structured such that the menu has a hierarchy. A setting menu used to enable a forced operation to forcibly stop the irradiating operation is provided as a lower level in the hierarchical structure of the “menu” button  67 . When the user presses the “menu” button  67  a plurality of times, a setting key used to enable the forced operation to forcibly stop the irradiating operation is displayed on the display unit  64 . When the user presses the “up” or “down” button to select the setting key associated with the forced operation and then presses the “enter” button  68 , a signal associated with the forced operation is transmitted to the indoor unit  2 . As described above, such a plurality of hierarchical operations, which make a forced operation complicated, are required to enable the forced operation to forcibly stop the irradiating operation, so that it is possible to prevent the user from stopping the irradiating operation. The forced operation enabled by the forced operation unit (pressing the “menu” button  67  in a hierarchical manner) is different from the stop operation (pressing the “ON/OFF” button  66 ) performed to stop the air conditioning operation and the stop operation performed to stop the second maintenance operation. Since the forced operation is different from the stop operation to stop the air conditioning operation and the stop operation to stop the maintenance operation, it is possible to prevent the user from stopping the irradiating operation. 
     The display unit  64  may be any type of display device, and is, for example, a liquid crystal display device. The control unit  16  controls the display unit  64  to display details of information, message, or the like transmitted from the air conditioner  1 . The display unit  64  of the remote control  17  acts as a notification unit and displays various messages about operation. For example, a warning message is displayed on the display unit  64  when the forced operation is performed on the ultraviolet rays irradiating operation. 
     In some embodiments, the remote control  17  may be further equipped with a speaker that acts as the notification unit. The control unit  16  controls the speaker to output various messages about operation in an audio form. 
     According to the present embodiment, an operation unit used to start or stop the normal operation of the air conditioner  1  and to start or stop the second maintenance operation of the air conditioner  1  is provided as the “ON/OFF” button  66  of the remote control  17 . In some embodiments, the operation unit may be provided in the indoor unit  2 . 
     Next, the normal operation and maintenance operation of the air conditioner  1  will be described. 
     [Normal Operation and Maintenance Operation] 
     (1) Normal Operation 
     The normal operation includes the cooling operation, the dehumidifying operation, and the heating operation. During the normal operation, the compressor  6  is driven, and the opening of the expansion valve  10  is reduced to a predetermined degree, thereby causing the refrigerant to circulate through the refrigerant circuit and causing the indoor heat exchanger  4  to function as a condenser or an evaporator. Further, when the indoor fan  5  is driven, air is drawn into the indoor unit  2  through the intake port, flows through the indoor heat exchanger  4 , and then blows out from the blow-out port  34  into the room. This allows the room to be cooled, dehumidified, or heated. 
     (2) Maintenance Operation 
     The maintenance operation is performed to keep the indoor heat exchanger  4 , the filter  47 , and the drain pan  33 , which are components built in the indoor unit  2 , clean. The maintenance operation includes, for example, the internal cleaning operation, the filter cleaning operation, and the ultraviolet rays irradiating operation, and any operation to keep the components built in the indoor unit  2  clean may belong to the maintenance operation. For example, assuming that the ultraviolet rays irradiating operation belongs to the first maintenance operation, the internal cleaning operation, the filter cleaning operation, and the other cleaning operation belong to the second maintenance operation. 
     The internal cleaning operation is provided to suppress propagation of bacteria, mold, or the like in the indoor unit  2 . During the internal cleaning operation, a blowing operation and heating operation are performed for a predetermined time after performing the cooling operation or the dehumidifying operation to dry the indoor heat exchanger  4 . This allows the inside of the indoor unit  2  to be kept clean. 
     The filter cleaning operation is provided to automatically clean the filter  47 . During the filter cleaning operation, the filter cleaner  43  is brought into operation to clean the filter  47 . This makes it possible to automatically remove dust adhering to the filter  47  to keep the inside of the indoor unit  2  clean. 
     The ultraviolet rays irradiating operation is provided to suppress propagation of bacteria, mold, or the like in the indoor unit  2 . During the ultraviolet rays irradiating operation, after the cooling operation or the dehumidifying operation, an irradiation area such as the indoor heat exchanger  4 , the filter  47 , or the drain pan  33  where bacteria, mold, or the like easily propagates is irradiated with the ultraviolet rays for a predetermined time. This makes it possible to sterilize the irradiation area to keep the inside of the indoor unit  2  clean. 
     The control unit  16  causes the maintenance operation to be automatically activated after the air conditioning operation is stopped. The control unit  16  determines that the maintenance operation is necessary when an accumulated time during which the air conditioning operation has been performed is equal to or longer than a predetermined time, and causes the maintenance operation to be automatically activated after the air conditioning operation is stopped. Alternatively, the control unit  16  causes the maintenance operation to be activated at a predetermined timing set as necessary by the user and after the air conditioning operation is stopped. 
     [Control of Maintenance Operation] 
     Next, the control of the maintenance operation of the air conditioner  1  will be described with reference to  FIGS. 6 and 7 .  FIG. 6  is a timing chart of the maintenance operation of the air conditioner  1 .  FIG. 7  is a control flowchart of the maintenance operation of the air conditioner  1 . 
     In the air conditioner  1 , when the cooling operation is selected by operation of the remote control  17  performed by the user, the control unit  16  performs the cooling operation desired by the user at an operation start time t 0  shown in  FIG. 6  to place the air conditioner  1  in the cooling operation over a predetermined period of time (step S 1 ). 
     In step S 2 , for example, the control unit  16  determines whether the stop operation of pressing the “ON/OFF” button  66  has been performed. When the stop operation has not been performed (NO in step S 2 ), the process waits until the stop operation is performed. When the stop operation has been performed (YES in step S 2 ), the process proceeds to step S 3 . 
     In step S 3 , the control unit  16  stops the cooling operation and performs the maintenance operation at a stop operation time t 1  shown in  FIG. 6 . Specifically, the control unit  16  performs at least either the internal cleaning operation or the filter cleaning operation as the second maintenance operation, and the ultraviolet rays irradiating operation as the first maintenance operation. As a result, both the second maintenance operation and the first maintenance operation (ultraviolet rays irradiating operation) are performed. 
     In step S 4 , for example, the control unit  16  determines whether the stop operation of pressing the “ON/OFF” button  66  has been performed. When the stop operation has not been performed (NO in step S 4 ), the process waits until the stop operation is performed. When the stop operation has been performed (YES in step S 4 ), the process proceeds to step S 5 . 
     In step S 5 , the control unit  16  stops the internal cleaning operation or the filter cleaning operation as the second maintenance operation and continues the ultraviolet rays irradiating operation as the first maintenance operation at a stop time t 2  shown in  FIG. 6 . Stopping the second maintenance operation in response to the stop operation on the second maintenance operation performed by the user makes it possible to reflect the intention of the user to stop the second maintenance operation. 
     In step S 6 , the control unit  16  determines whether the forced operation of pressing the “menu” button  67  a plurality of times, pressing the “up” or “down” button, and pressing the “enter” button  68  has been performed. When the forced operation has not been performed (NO in step S 6 ), the process waits until the forced operation is performed. When the forced operation has been performed (YES in step S 6 ), the process proceeds to step S 7 . 
     In step S 7 , the control unit  16  controls the display unit  64  to perform a notification operation. As described above, the display unit  64  acts as the notification unit to output a warning message in a visual form when the forced operation is performed on the ultraviolet rays irradiating operation. The display unit  64  displays, for example, “Sterilization has not been completed yet. Really want to stop it?” as the warning message when the forced operation is performed on the ultraviolet rays irradiating operation. Alternatively, the speaker (notification unit  45 ) provided in the indoor unit  2  or the speaker (not illustrated) provided in the remote control  17  can output a similar warning message in an audio form. This notification can make the user aware that the stop of the irradiating operation is not preferable for sterilization 
     In step S 8 , the control unit  16  controls the irradiation unit  40  to forcibly stop the ultraviolet rays irradiating operation at a forced stop time t 3  shown in  FIG. 6 . Specifically, the control unit  16  controls the irradiation unit  40  to turn off the irradiation unit  40 . In step S 7 , it is possible to reflect the intention of the user by making the user aware that the stop of the irradiating operation is not preferable for sterilization t and then stopping the irradiating operation. When the irradiation unit  40  is turned off, the control of the maintenance operation is brought to an end. 
     In the air conditioner  1 , the irradiating operation continues even when the stop operation to stop the maintenance operation is performed, thereby allowing the inside of the indoor unit  2  to be kept clean. 
     The embodiment of the present disclosure has been described above. However, it should be understood that specific configurations of the present disclosure are not limited to those described in the embodiment. The scope of present disclosure is indicated by not only the embodiment described above but also the appended claims and further includes equivalents of the claims and all modifications within the scope of the claims. 
     Note that an operation unit used to stop the second maintenance operation of the maintenance operation and an operation unit used to stop the air conditioning operation may be separately provided. 
     Note that the second maintenance operation includes the internal cleaning operation, the filter cleaning operation, and the other cleaning operation. Therefore, the second maintenance operation includes: for example, only the internal cleaning operation; only the filter cleaning operation; the internal cleaning operation and the filter cleaning operation; only the other cleaning operation; the internal cleaning operation and the other cleaning operation; the filter cleaning operation and the other cleaning operation; or the internal cleaning operation, the filter cleaning operation, and the other cleaning operation. 
     REFERENCE SIGNS LIST 
     
         
         
           
               1  air conditioner 
               2  indoor unit 
               3  outdoor unit 
               4  indoor heat exchanger (heat exchanger) 
               6  compressor 
               7  four-way switching valve 
               8  outdoor heat exchanger (heat exchanger) 
               10  expansion valve 
               11  accumulator 
               14  indoor-unit controller (control unit) 
               15  outdoor-unit controller (control unit) 
               16  control unit 
               17  remote controller (remote control) 
               30  casing 
               31  casing body 
               31   a  front part 
               31   b  upper part 
               31   c  rear part 
               31   d  lower part 
               32  front panel 
               33  drain pan (an irradiation area to-be-irradiated) 
               34  blow-out port 
               35  first partition wall 
               36  second partition wall 
               37  blow-out flow path 
               38  drain port 
               39  drain hose 
               40  irradiation unit 
               41  first horizontal flap 
               43  filter cleaner 
               45  notification unit 
               47  filter 
               51  second horizontal flap 
               61  remote control casing 
               62  panel 
               63  front surface 
               64  display unit (notification unit) 
               65  transmitter 
               66  “ON/OFF” button (operation unit) 
               67  “menu” button (forced operation unit) 
               68  “enter” button 
             L 1 , L 2  connection pipe 
             T 1  outdoor heat exchanger temperature sensor 
             T 2  outdoor air temperature sensor 
             T 3  indoor heat exchanger temperature sensor 
             T 4  indoor temperature sensor 
             t 0  operation start time 
             t 1  stop operation time 
             t 2  stop time 
             t 3  forced stop time 
             W wall surface