JP2002349927A - Air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an air conditioner, in which even if misconnections are made at installation of multi-room type air conditioners, the improper connection is and determined surely and automatically, and the load applied on a compressor, etc., in the operation of the air conditioner can be reduced. SOLUTION: Switching, between an heating determination operation and a cooling determination operation, is done on the basis of the room temperature detected by room-temperature thermistors 9A-9C; the operations for heating determination or cooling determination are conducted for respective indoor units 8A-8C; thus misconnections in a refrigerant pipe or a connection cable is determined on the basis of temperatures detected by thermistors 7A-7C, and 17A-17C which detect the temperatures of the parallel refrigerant-circuits including indoor heat-exchangers 6A-6C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-chamber air conditioner, and more particularly to a multi-chamber air conditioner capable of automatically judging a connection state of a refrigerant pipe or a connection cable.

[0002]

2. Description of the Related Art As shown in Japanese Patent Application Laid-Open No. 9-133442, as a conventional multi-room air conditioner, when a multi-room air conditioner is installed, each indoor unit and an outdoor unit are arranged. In order to make it possible to easily identify an erroneous connection of refrigerant pipes connecting the refrigerant pipes, the refrigerant discharged from the compressor is passed through at least the outdoor heat exchanger, and then the throttle means, the first on-off valve, Exchanger, and arbitrarily circulates through a plurality of refrigerant circuits including the second on-off valve, and performs a cooling operation so as to return to the compressor,
The first and second on-off valves are opened for each refrigerant circuit, the temperature of the indoor heat exchanger corresponding to the opened on-off valves is detected after a lapse of a predetermined time, and a comparison result between the detected value and a preset set value From the erroneous connection of the refrigerant pipe is determined, and when the erroneous connection of the refrigerant pipe is detected, an abnormality is displayed by the display means of the corresponding indoor unit, and the abnormality display is continuously displayed for a predetermined time, and the series of In some cases, a start button for starting a control operation is provided in an outdoor unit.

[0003]

However, in such a conventional air conditioner, cooling operation is performed irrespective of the indoor temperature and the outdoor temperature, and the detected temperature of the indoor heat exchanger is compared with a preset set temperature. The erroneous connection is determined from the result, and no consideration is given to changing the operation state based on the indoor temperature or the outdoor temperature at the time of the determination.
For this reason, when the indoor temperature or the outdoor temperature is particularly low, for example, when the installation work of the air conditioner is performed in winter, the cooling circuit cannot be operated due to the protection circuit, or the cooling operation is forcibly performed. Even if it is performed, it is difficult to reliably detect the temperature drop of the indoor heat exchanger due to the low indoor temperature, or in some cases, the refrigerant cannot return to the compressor because it cannot evaporate in the indoor heat exchanger. There is a problem that the load is increased by the liquid compression.

[0004] It is an object of the present invention to provide a protection circuit that does not disable a misconnection even if the misconnection determination operation is performed when the room temperature is particularly low, such as in winter, and that the reliability is low. An object of the present invention is to provide an air conditioner capable of performing a high determination and preventing an increase in load due to liquid compression.

[0005]

To achieve the above object, the present invention is characterized in that a compressor, a cooling / heating switching valve, an outdoor heat exchanger, a throttle mechanism, and a plurality of indoor heat exchangers are connected by refrigerant piping. Constructing a refrigeration cycle and forming a parallel refrigerant circuit with the plurality of indoor heat exchangers, and the indoor unit with respect to an outdoor unit having the compressor, the cooling / heating switching valve, the outdoor heat exchanger, and the throttle mechanism. A plurality of indoor units having a heat exchanger are connected via a refrigerant pipe and a connection cable, and a means for detecting an indoor temperature and a means for detecting a temperature of the parallel refrigerant circuit are provided. A multi-room air conditioner capable of performing a connection determination operation, wherein the erroneous connection determination operation switches between a heating determination operation and a cooling determination operation based on an indoor temperature detected by the indoor temperature detecting unit, this The configuration is such that the chamber determination operation or the cooling determination operation is performed for each indoor unit, and the incorrect connection determination of the refrigerant pipe or the connection cable is performed based on the temperature detected by the means for detecting the temperature of the parallel refrigerant circuit. It is in.

[0006]

Embodiments of the present invention will be described below with reference to the drawings.

First, an overall configuration of a multi-room air conditioner according to a first embodiment of the present invention will be described with reference to FIG. FIG.
1 is a configuration diagram of a multi-room air conditioner according to a first embodiment of the present invention.

In FIG. 1, 1 is a compressor, 2 is a switching valve for cooling and heating, 3 is an outdoor heat exchanger, 4A to 4C are on-off valves,
5A to 5C are throttle mechanisms that can be fully closed, 6A to 6C are indoor heat exchangers, 7A to 7C are heat exchanger thermistors that are means for detecting indoor heat exchanger temperatures, 8A to 8C are indoor units, and 9A to 9C.
9C is a room temperature thermistor which is a means for detecting the indoor temperature, 1
0A to 10C are control units of the indoor unit, 11 is a control unit of the outdoor unit, 12 is an outdoor temperature thermistor which is an outdoor temperature detecting means, 13 is an outdoor display unit for displaying an outdoor failure or the like, and 14 is a misconnection determination. An operation start button, 15A to 15C, is an indoor display section for displaying an indoor failure or the like.

The refrigeration cycle includes a compressor 1, a cooling / heating switching valve 2, an outdoor heat exchanger 3, a plurality of throttle mechanisms 5A to 5C, a plurality of indoor heat exchangers 6A to 6C, and a plurality of on-off valves 4A to 4C.
Are connected by a refrigerant pipe. The plurality of throttle mechanisms 5A to 5C, the plurality of indoor heat exchangers 6A to 6C, and the plurality of on-off valves 4A to 4C are connected in series, respectively, and the refrigerant circuit in series is connected to the outdoor heat exchanger 3 and The refrigerant circuit is connected in parallel to the switching valve 2 to form a parallel refrigerant circuit.

[0010] By operating the switching valve 2, it is possible to switch between the refrigeration cycle of the cooling operation and the heating operation. Refrigerant in the refrigeration cycle of the cooling operation passes through the compressor 1, the switching valve 2, and the outdoor heat exchanger 3, passes through a throttling mechanism 5A, a series refrigerant circuit of the indoor heat exchanger 6A and the on-off valve 4A, a throttling mechanism 5B, The refrigerant flows through a parallel refrigerant circuit composed of an indoor heat exchanger 6B and an on-off valve 4B in series and a throttle mechanism 5C, an indoor heat exchanger 6C and an on-off valve 4C in series. To return to the compressor 1. The refrigerant in the refrigeration cycle of the heating operation passes through the compressor 1 and the switching valve 2, passes through the on-off valve 4A, the indoor heat exchanger 6A, and the refrigerant circuit in series with the throttle mechanism 5A.
B, a series refrigerant circuit of an indoor heat exchanger 6B and a throttle mechanism 5B, an on-off valve 4C, an indoor heat exchanger 6C and a throttle mechanism 5C.
Flows through a parallel refrigerant circuit constituted by a series of refrigerant circuits, and further passes through an outdoor heat exchanger 3 from a switching valve 2 to a compressor 1.
Return to

The outdoor unit includes a compressor 1, a switching valve 2, an outdoor heat exchanger 3, throttle mechanisms 5A to 5C, on-off valves 4A to 4C, an outdoor control unit 11, an outside temperature thermistor 12, an outdoor display unit 1.
3. Start button 14, outdoor fan (not shown)
Etc. are arranged. On the other hand, the indoor unit 8A includes an indoor heat exchanger 6A, an indoor heat exchanger thermistor 7A, a room temperature thermistor 9A, an indoor control unit 10A, an indoor display unit 15A, and an indoor fan (not shown). In 8B,
Indoor heat exchanger 6B, indoor heat exchanger thermistor 7B, room temperature thermistor 9B, indoor control unit 10B, indoor display unit 1
5B and an indoor fan (not shown),
In C, an indoor heat exchanger 6C, an indoor heat exchanger thermistor 7C, a room temperature thermistor 9C, an indoor control unit 10C, an indoor display unit 15C, and an indoor fan (not shown) are arranged. Note that FIG. 1 schematically shows that only the indoor heat exchangers 6A to 6C are arranged in the indoor units 8A to 8C. The outdoor unit and the indoor units 8A to 8C are connected by a refrigerant pipe and a connection cable.

The outdoor control unit 11 includes an indoor control unit 10.
A to C, input buttons from the start button 14, the outside temperature thermistor 12, etc., the compressor 1, the switching valve 2, the outdoor fan, the on-off valves 4A to 4C, the throttle mechanisms 5A to 5A
C and controls the outdoor display unit 13 and the like, and outputs control signals to the indoor control units 10A to 10C.

The indoor control units 10A to 10C receive input signals from the indoor heat exchanger thermistors 7A to 7C, the room temperature thermistors 9A to 9C, the outdoor control unit 11, and the like, and receive an indoor blower and an indoor display unit. 15A to 15C, and outputs a control signal to the outdoor control unit 11.

The outdoor display unit 13 includes the indoor units 8A to 8A.
A plurality of LED display units corresponding to C are provided, and the LED display unit for failure display conventionally used also serves as the erroneous connection display in the present invention. This makes it possible to determine the connection state with an inexpensive configuration.

Next, the operation of the erroneous connection determination operation for determining the connection state of the refrigerant pipe or the connection cable in the multi-room air conditioner of the present embodiment will be described with reference to FIGS. FIG. 2 is an operation flowchart in the misconnection determination operation of the multi-room air conditioner in FIG. 1, and FIG. 3 is a diagram showing criteria for the misconnection determination operation.

Outdoor control unit 11 and indoor control units 10A-1
0C starts the control of the erroneous connection determination operation by pressing the start button 14 arranged on the outdoor unit (step 21). When the start button 14 is pressed, the room temperature is detected by the room temperature thermistors 9A to 9C and taken into the room control units 10A to 10C, and the outside temperature is detected by the outside temperature thermistor 12 and taken into the room control unit 11. (Step 22). Then, the detected indoor temperature is sent from the indoor control units 10A to 10C to the outdoor control unit 11.

On the basis of the detected indoor temperature and outdoor temperature, the outdoor control section 11 determines the determination operation mode (step 23). In this determination, when the indoor temperature and the outdoor temperature are low, the heating determination operation mode is selected, and when the indoor temperature and the outdoor temperature are high, the cooling determination operation mode is selected. Although the determination of the determination operation mode can be made based only on the detected indoor temperature, a more appropriate determination can be made based on both the outdoor temperature and the indoor temperature because the outdoor load can be considered. In the present embodiment, as shown in FIG. 3, as shown in FIG. 3, each mode region is divided based on the correlation between the indoor temperature and the outdoor temperature, so that a more appropriate determination can be made.

When the heating determination operation mode is selected in step 23, the outdoor control unit 11 switches the switching valve 2 to the heating side (step 31). And on-off valve 4A ~
On-off valve 4A corresponding to first indoor unit 8A from 4C
Only open and others closed (step 3
2) The throttle mechanisms 5A to 5C are set to a state where only the throttle mechanism 5A corresponding to the on-off valve 4A is opened and the others are closed from a predetermined opening degree (step 33), and the compressor 1 is operated (step 33). 34). After a predetermined time, the temperatures of the indoor heat exchangers 6A to 6C are detected by the heat exchanger thermistors 7A to 7C (step 35), and are taken into the indoor control unit 10A. The temperatures of the indoor heat exchangers 6A to 6C are sent from the indoor control units 10A to 10C to the outdoor control unit 11.

The outdoor controller 11 determines whether the connection between the refrigerant pipe and the connection cable is normal (step 36). This determination is based on the detected indoor heat exchangers 6A-6A
This is performed by comparing the temperature of C with a preset temperature. That is, if the connection of the indoor unit 8A is normal, the detected temperature of the indoor heat exchanger 6A exceeds the set temperature by utilizing the fact that the temperature of the indoor heat exchanger 6A increases by the above-described heating determination operation. If so, it is determined that the connection is normal, and the process proceeds to step 41. Since the load changes depending on the indoor temperature and the temperature rise of the indoor heat exchanger also changes,
The set temperature to be compared can be determined more accurately by correcting the set temperature with the room temperature detected by the room temperature thermistors 7A to 7C.

In step 36, when the temperature rise of the indoor heat exchanger 6A does not reach the set value, it is determined that the connection is incorrect, and it is determined whether the temperature rise of the indoor heat exchangers 6B and 6C has reached the set value. If the indoor heat exchanger that has reached this set value, for example, the indoor heat exchanger 6B is erroneously connected, it is determined that the indoor unit 8A and the indoor unit 8B have been switched and are erroneously connected, and the outdoor display is displayed. An error display such as turning on a lamp corresponding to the indoor units 8A and 8B is performed on the unit 13 (step 37), and an error display is further performed on the indoor display units 15A and 15B (step 38). The determination may be made based on whether a temperature difference between the temperature of the indoor heat exchanger 6A and the indoor temperature is equal to or greater than a set value. Then, the connection circuit between the indoor unit 8A and the indoor unit 8B is switched, and the erroneous connection is automatically repaired (step 3).
9). As a result, erroneous connection can be repaired very easily. The automatic switching can be easily realized by providing the outdoor unit with a relay circuit.

Then, in step 41, the indoor unit 8
The misconnection of B is determined. This step 41 corresponds to the indoor unit 8 in steps 32 to 38 described above.
A similar operation to the determination of the misconnection of A is performed, and the on-off valve 4A, the throttle mechanism 5B, the indoor heat exchanger 6B, and the indoor display unit 15B are changed to the on-off valve 4B, the throttle mechanism 5A, the indoor heat exchanger 6A, and the indoor display unit 15A. Therefore, detailed description will be omitted.

Then, in step 42, the indoor unit 8
The erroneous connection determination of C is performed. This step 42 is performed by the indoor unit 8 in steps 32 to 38 described above.
The same operation as the determination of the erroneous connection of A is performed. Therefore, detailed description will be omitted.

When the cooling determination operation mode is selected in step 23, the outdoor control unit 11 switches the switching valve 2 to the cooling side (step 51). Then, an erroneous connection determination of the indoor unit 8A is performed (step 5).
2). In step 52, the same operation as the determination of the erroneous connection of the indoor unit 8A in steps 32 to 38 when the above-described heating determination operation mode is selected is performed, and therefore, detailed description is omitted. In addition, since the erroneous connection determination in step 52 is based on the cooling operation, the determination criterion is different from the heating operation, in that the determination criterion is different in that the temperature of the indoor heat exchangers 6A to 6C is reduced. .

Then, in step 53, the indoor unit 8
The misconnection of B is determined. In this step 53, the same operation as that of the erroneous connection determination of the indoor unit 8A in the above-described step 52 is performed, and thus the detailed description is omitted. In step 54, the erroneous connection of the indoor unit 8C is determined. This step 54 is the same as step 5 described above.
Since the same operation as that of the erroneous connection determination of the indoor unit 8A in 2 is performed, detailed description is omitted.

Next, an overall configuration of a multi-room air conditioner according to a second embodiment of the present invention will be described with reference to FIG. FIG.
FIG. 2 is a configuration diagram of a multi-room air conditioner according to a second embodiment of the present invention. In FIG. 4, the same or corresponding components as those in FIG. 1 are denoted by the same reference numerals.

In this embodiment, there is no opening / closing valve on the upstream side of the indoor heat exchangers 6A to 6C in the refrigerant circulation at the time of heating, and the indoor unit whose other indoor units are stopped during the heating is also used. This is a multi-room air conditioner in which a refrigerant is circulated. In recent years, such a configuration is increasing in order to reduce costs.
The indoor fans 16A to 16C can change the air volume. Also, the pipe thermistor 17A ~
17C detects the temperature of the refrigerant after passing through the indoor heat exchangers 6A to 6C during heating, and is disposed in the outdoor unit. Except for these points, the configuration is basically the same as that of FIG.

Next, the operation of the erroneous connection judging operation for judging the connection state of the refrigerant pipe or the connection cable in the multi-room air conditioner of this embodiment will be described with reference to FIG. FIG.
FIG. 7 is an operation flowchart in the misconnection determination operation of the multi-room air conditioner in FIG. 4.

Outdoor control unit 11 and indoor control units 10A-1
0C starts the control of the erroneous connection determination operation by pressing the start button 14 arranged on the outdoor unit (step 55). When the start button 14 is pressed, the room temperature is detected by the room temperature thermistors 9A to 9C and taken into the room control units 10A to 10C, and the outside temperature is detected by the outside temperature thermistor 12 and taken into the room control unit 11. (Step 56). Then, the detected indoor temperature is sent from the indoor control units 10A to 10C to the outdoor control unit 11.

Based on the detected indoor temperature and outdoor temperature, the outdoor control section 11 determines the determination operation mode (step 57). In this determination, when the indoor temperature and the outdoor temperature are low, the heating determination operation mode is selected, and when the indoor temperature and the outdoor temperature are high, the cooling determination operation mode is selected. This determination is made based on the mode area of FIG. 3 used in the first embodiment.

When the heating determination operation mode is selected in step 57, the outdoor control unit 11 switches the switching valve 2 to the heating side (step 61). And indoor fan 1
6A to 16C are operated at a low speed or a very low air volume (step 62). The throttle mechanisms 5A to 5C are set to a predetermined opening degree (step 63), and the compressor 1 is operated (step 64). After a predetermined time, pipe thermistor 1
After the refrigerant temperature after passing through the indoor heat exchangers 6A to 6C is detected in 7A to 17C (step 65), the indoor fan 16
The air volume is increased only for A (step 66). Outdoor control unit 11
It is taken in. After a predetermined time, the refrigerant temperature after passing through the indoor heat exchangers 6A to 6C is detected again by the pipe thermistors 17A to 17C (step 67).

Then, the outdoor controller 11 determines whether the connection of the refrigerant pipe and the connection cable is normal (step 68). This determination is made by comparing the temperature detected by the pipe thermistors 17A to 17C before increasing the air flow with the temperature detected after a predetermined time after increasing the air flow. That is, if the difference between the temperature before the increase in the air volume detected by the pipe thermistor 17A and the temperature after the increase is equal to or higher than the preset temperature, it is determined that the connection is normal, and the process proceeds to step 72. The indoor fan 16A
In order to prevent the temperature from decreasing to the refrigerant temperature after passing through the indoor heat exchangers 6B and 6C due to the effect of increasing the air volume of the air, the air volume of the indoor fans 16B and 16C, which were turned at a very low air volume, is further reduced, or By stopping, more reliable determination can be made. Also, since the load changes depending on the indoor temperature and the temperature difference between before and after increasing the refrigerant after passing through the indoor heat exchanger 6A also changes, the set temperature to be compared should be corrected based on the indoor temperature detected by the room temperature thermistor 7A. Thus, the determination can be made more accurately.

If it is determined in step 69 that the difference between the temperature before the increase in the air flow detected by the pipe thermistor 17A and the temperature after the increase does not reach the preset temperature, it is determined that the connection is incorrect. You. In this case, the difference between the temperature detected by the pipe thermistors 17B and 17C before increasing the air flow and the temperature detected after a predetermined time after increasing the air flow is compared with a set temperature or more, and the difference is reached above the set temperature. If it is determined that the other pipe thermistor, for example, the pipe thermistor 17B, is incorrectly connected, the indoor unit 8A
And the indoor unit 8B are switched and are determined to be erroneously connected. As a result, the indoor unit 8A,
For example, an error display corresponding to 8B, such as turning on a lamp, is performed (step 69).
An error is displayed on 5A and 15B (step 7).
0). Then, the connection circuit between the indoor unit 8A and the indoor unit 8B is replaced to automatically repair the erroneous connection (step 7).
1). As a result, erroneous connection can be repaired very easily. This automatic switching can be easily realized by providing a relay circuit.

Then, in step 72, the indoor unit 8
The misconnection of B is determined. This step 2 is based on the indoor unit 8A in steps 62 to 71 described above.
Since the same operation as the erroneous connection determination is performed, detailed description is omitted. In step 73, the erroneous connection of the indoor unit 8C is determined. In this step 73, the same operation as the above-described determination of the erroneous connection of the indoor unit 8A in steps 62 to 71 is performed, and therefore, detailed description is omitted.

When the cooling determination operation mode is selected in step 63 described above, the outdoor control unit 11 switches the switching valve 2 to the cooling side (step 81). Then, an erroneous connection determination of the indoor unit 8A is performed (step 8).
2). In this step 82, the same operation as the above-described erroneous connection determination of the indoor unit 8A in step 52 of the first embodiment is performed, and therefore, detailed description is omitted. Hereinafter, the erroneous connection determination of the indoor unit 8B is performed in step 83, and the erroneous connection determination of the indoor unit 8C is performed in step 84. However, since it is the same as step 82, detailed description will be omitted.

In the embodiment described above, the heating determination operation and the cooling determination operation are switched based on the room temperature detected by the room temperature thermistors 9A to 9C, and the heating determination operation or the cooling determination operation is performed in each of the indoor units 8A to 8C. Thermistors 7A to 7C, 17A to 17C for detecting the temperature of the parallel refrigerant circuits including the indoor heat exchangers 6A to 6C by performing the operation every 8C
In the case where the indoor temperature is particularly low, for example, when the installation work of the air conditioner is performed in winter, the heating determination operation is performed. Is performed, and an erroneous connection is determined. As a result, the protection circuit for the cooling operation does not work to make the erroneous connection determination impossible, and the change in the detected temperature serving as the criterion for the heating determination operation is reliably detected to make a highly reliable determination. In addition, it is possible to prevent the refrigerant from evaporating in the indoor heat exchangers 6A to 6C and returning to the compressor 1 as a liquid to increase the load due to the liquid compression.

[0036]

According to the present invention, even if the misconnection determination operation is performed when the room temperature is particularly low, such as in winter, the protection circuit is not activated and the misconnection determination is not impossible. It is possible to obtain an air conditioner capable of performing highly reliable determination and preventing an increase in load due to liquid compression.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a multi-room air conditioner according to a first embodiment of the present invention.

FIG. 2 is an operation flowchart of the multi-room air conditioner of FIG. 1 in an erroneous connection determination operation.

FIG. 3 is a diagram showing a reference for the erroneous connection determination operation.

FIG. 4 is a configuration diagram of a multi-room air conditioner according to a second embodiment of the present invention.

FIG. 5 is an operation flowchart in the misconnection determination operation of the multi-room air conditioner in FIG. 4;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Compressor, 2 ... Switching valve, 3 ... Outdoor heat exchanger, 4A-4
C: open / close valve, 5A to 5C: throttle mechanism, 6A to 6C: indoor heat exchanger, 7A to 7C: indoor heat exchanger thermistor, 8
A to 8C: indoor unit, 9A to 9C: room temperature thermistor, 1
0A to 10C: indoor control unit, 11: outdoor control unit, 12 ...
Outside temperature thermistor, 13 outdoor display unit, 14 start button, 15 indoor display unit, 16A-16C indoor fan, 17A-17C piping thermistor.

Claims (5)

[Claims] A refrigeration cycle is formed by connecting a compressor, a cooling / heating switching valve, an outdoor heat exchanger, a throttle mechanism, and a plurality of indoor heat exchangers with a refrigerant pipe, and the plurality of indoor heat exchangers are connected in parallel. A circuit is formed, and a plurality of indoor units having the indoor heat exchanger are connected to the compressor, the air conditioning switching valve, the outdoor heat exchanger, and the outdoor unit having the throttling mechanism via a refrigerant pipe and a connection cable. A multi-room air conditioner comprising means for detecting the temperature of the indoor refrigerant circuit and means for detecting the temperature of the parallel refrigerant circuit, and capable of determining whether the refrigerant pipe or the connection cable has an incorrect connection. The erroneous connection determination operation switches between a heating determination operation and a cooling determination operation based on the indoor temperature detected by the indoor temperature detecting means, performing the heating determination operation or the cooling determination operation for each indoor unit, Previous The air conditioner according to claim 1, wherein the erroneous connection of the refrigerant pipe or the connection cable is determined based on the temperature detected by the means for detecting the temperature of the parallel refrigerant circuit. 2. A refrigeration cycle is formed by connecting a compressor, a cooling / heating switching valve, an outdoor heat exchanger, a throttle mechanism, and a plurality of indoor heat exchangers with a refrigerant pipe, and a refrigeration cycle is provided upstream of the indoor heat exchanger during cooling. A refrigerant circuit having a closeable throttle mechanism or an on-off valve and having an on-off valve on the upstream side of the indoor heat exchanger during heating is connected in parallel, and the compressor, the cooling / heating switching valve, the outdoor heat exchanger, and A plurality of indoor units having the indoor heat exchanger are connected to an outdoor unit having the throttle mechanism via a refrigerant pipe and a connection cable, and a means for detecting an indoor temperature and a temperature of the indoor heat exchanger are detected. A multi-room air conditioner comprising means for performing an erroneous connection determination operation of the refrigerant pipe or the connection cable, wherein the erroneous connection determination operation is performed based on an indoor temperature detected by the indoor temperature detecting means. Heating judgment operation and cooling judgment Switching to a constant operation, and at the time of the heating determination operation, opening and closing the on-off valve on the upstream side of the indoor heat exchanger for each indoor unit and detecting the temperature of the corresponding indoor heat exchanger to set the indoor heat exchanger It is determined whether the temperature rises above the temperature or the temperature difference from the indoor temperature is equal to or more than the set value. During the cooling operation, the throttle mechanism or the on-off valve on the upstream side of the heat exchanger is opened for each indoor unit and An air conditioner characterized by detecting a temperature of the indoor heat exchanger and determining whether the temperature falls below a set value or a temperature difference from the indoor temperature is above a set value. 3. A refrigeration cycle is formed by connecting a compressor, a cooling / heating switching valve, an outdoor heat exchanger, a throttle mechanism, and a plurality of indoor heat exchangers with a refrigerant pipe, and a refrigeration cycle is provided upstream of the indoor heat exchanger during cooling. A refrigerant circuit having a closeable throttle mechanism or an on-off valve is connected in parallel, and the indoor heat exchanger is provided for the compressor, the cooling / heating switching valve, the outdoor heat exchanger, and an outdoor unit having the throttle mechanism. A means for connecting a plurality of indoor units via a refrigerant pipe and a connection cable to detect an indoor temperature, a means for detecting a refrigerant temperature on the downstream side of the indoor heat exchanger during heating, and a flow rate of air flowing through the indoor heat exchanger A multi-room air conditioner comprising an indoor fan capable of changing the temperature of the refrigerant pipe or the connection cable, and capable of performing an erroneous connection determination operation of the refrigerant pipe or the connection cable, wherein the erroneous connection determination operation is detected by the means for detecting the indoor temperature Room temperature Switching between the heating determination operation and the cooling determination operation, and in the heating determination operation, the air flow rate of the indoor fan is changed for each indoor unit, and the corresponding refrigerant temperature on the downstream side of the indoor heat exchanger is detected. Determine whether the temperature change is greater than or equal to a set value, during the cooling operation, open the throttle mechanism or the on-off valve on the upstream side of the heat exchanger for each indoor unit and detect the temperature of the corresponding indoor heat exchanger. An air conditioner that determines whether the temperature of the air conditioner is lower than a set value or a temperature difference between the room temperature and the room temperature is higher than a set value. 4. The indoor temperature detected by the means for detecting the indoor temperature and the outdoor temperature detected by the means for detecting the outdoor temperature according to any one of claims 1 to 3, further comprising means for detecting the outdoor temperature. An air conditioner characterized by switching between a heating judgment operation and a cooling judgment operation based on the condition. 5. The air conditioner according to claim 1, further comprising means for automatically switching the connection of the indoor unit corresponding to the erroneous connection determination in the erroneous connection determination operation.