JPH0814634A - Air conditioner - Google Patents

Abstract

PURPOSE:To provide a highly reliable air conditioner capable of proper operation at all times by securely recovering a refrigerant accumulated in an indoor machine without causing complicated data transmission/reception control between an outdoor machine and the indoor machine. CONSTITUTION:Indoor machines B1, B2,...Bn judge whether a machine to be connected is an outdoor machine A or any of relay machines D1 to D3. Refrigerant recovery control is executed in which once operation of each indoor machine is stopped or interrupted, a refrigerant remaining in the indoor machine is forced to be recovered by the side of the outdoor machine A. Herein, in each indoor machine an inherent address is selected if a judgement result is the outdoor machine A, while inherent addresses of the relay machines D1 to D3 to be connected are selected, provided the judgement result is the relay machines D1 to D3. In the course of the operation of a compressor 1 count is incremented for each predetermined time. When a count value reaches a predetermined value corresponding to the selected inherent address, the refrigerant recovery control is started.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-type air conditioner in which a plurality of indoor units are connected to one outdoor unit.

[0002]

2. Description of the Related Art There is a multi-type air conditioner in which a plurality of indoor units are connected to a single outdoor unit via a pair of signal lines to air-condition a plurality of rooms at once. In this air conditioner, a flow rate adjusting valve is provided for each indoor unit, and the opening degree of each flow rate adjusting valve is controlled according to the required capacity of each indoor unit.

For example, for an indoor unit having a large required capacity, the opening of the flow rate adjusting valve is increased and the flow rate of the refrigerant is increased. For an indoor unit with a small required capacity, the opening of the flow rate adjusting valve is reduced to reduce the flow rate of the refrigerant.

For an indoor unit that does not require operation, or for an indoor unit (room temperature) in which the temperature of the room in which it is installed (indoor temperature) has reached a set value (operation interruption), the flow rate adjustment valve is fully closed to distribute the refrigerant. Stop and stop or interrupt the operation (thermo off).

By the way, when the operation of the indoor unit is stopped or interrupted, the refrigerant accumulates (sleeps) in the indoor unit, and the refrigerant circulation amount during the refrigeration cycle decreases.
If the refrigerant circulation amount is insufficient, a problem occurs such that sufficient air conditioning capacity cannot be obtained in the operating indoor unit.

Moreover, the refrigerant that collects also contains the lubricating oil that flows out from the compressor, so that the amount of lubricating oil that returns to the compressor is reduced, the oil level in the compressor is lowered, and the compressor locks. I have a concern.

Therefore, conventionally, control for recovering the refrigerant accumulated in the indoor unit to the outdoor unit side, that is, so-called refrigerant recovery control is executed. In this refrigerant recovery control, the flow rate adjustment valve, which is fully closed to stop or stop the operation, is opened to a predetermined opening for a certain period of time. As a result, the accumulated refrigerant receives the suction pressure of the compressor and is recovered to the outdoor unit side.

On the other hand, in the multi-type air conditioner, a unique address is set for each indoor unit, and time division data transmission / reception is performed between the outdoor unit and each indoor unit based on the unique address. This so-called bus communication has become the main type of multi-type because of the small number of wires and the simple wiring work.

Therefore, in controlling the refrigerant recovery,
The outdoor unit collects the transmission data from each indoor unit, grasps the operating state (stop or interruption) of each indoor unit, and sends a refrigerant recovery command as necessary. The refrigerant recovery command can be sent by a simultaneous method in which it is sent to all indoor units at once, or by an individual method in which it is sent in order to indoor units whose operation is stopped or interrupted.

[0010]

When a refrigerant recovery command is simultaneously sent from the outdoor unit to each indoor unit, the refrigerant recovery control is simultaneously started in all the indoor units whose operation is stopped or interrupted, and Refrigerant flows to all the indoor units that are suspended.

Therefore, for example, when the number of operating indoor units is, for example, 1 and all the remaining indoor units have stopped or suspended operation, a sufficient amount of refrigerant does not flow to the operating indoor units. , Will cause a lack of ability.

Further, the operating state of each indoor unit is not immediately transmitted to the outdoor unit, but reaches the outdoor unit after waiting for the timing of data transmission by time division. Therefore, in the method in which the refrigerant recovery command is individually sent from the outdoor unit to each indoor unit, in addition to the time waiting for the data of each indoor unit to reach the outdoor unit,
There is a waiting time for the refrigerant recovery command from the outdoor unit to reach each indoor unit.

The presence of the refrigerant recovery control in addition to such time waiting and turn waiting is a major factor that complicates data transmission / reception control between the outdoor unit and each indoor unit.

In a simultaneous cooling / warming type air conditioner capable of simultaneously performing different modes of cooling and heating in each indoor unit, a relay unit is interposed between the outdoor unit and each indoor unit,
The relay device switches the flow direction of the refrigerant to each indoor unit. This relay also relays data transmission / reception between the outdoor unit and each indoor unit, and in this case, the data transmission / reception control becomes more and more complicated, involving the refrigerant recovery control.

The present invention takes the above circumstances into consideration,
The purpose is to ensure that the refrigerant accumulated in the indoor unit is reliably collected and the proper operation is always possible without complicating the data transmission / reception control between the outdoor unit and each indoor unit. It is to provide an excellent air conditioner.

[0016]

An air conditioner according to a first aspect of the present invention connects a single outdoor unit and a plurality of indoor units directly or via a relay to connect a refrigerant pipe and a signal line, In an air conditioner that controls operation by transmitting and receiving data through a signal line, a refrigerant recovery control for recovering the refrigerant remaining in the indoor unit to the outdoor unit side when the operation of each indoor unit is stopped or interrupted. Control means for executing, a determination means provided in each indoor unit, for determining whether the connected device is an outdoor unit or a relay device, and the execution timing of the refrigerant recovery control as the determination result of the determination means. And a deciding means for deciding accordingly.

In the air conditioner of the second invention, the deciding means in the first invention selects and selects the unique address defined in the indoor unit or the relay device of the connection destination according to the determination result. A means for determining the execution timing of the refrigerant recovery control based on the unique address is provided.

In the air conditioner of the third invention, the determining means in the second invention selects the unique address of the indoor unit when the determination result is the outdoor unit, and the connection destination when the determination result is the relay unit. Means for selecting a unique address of the repeater is provided.

In the air conditioner of the fourth aspect of the invention, the determining means of the second or third aspect of the invention counts up every predetermined time during operation of the compressor, and the count value corresponds to the unique address. A means for determining the start of the refrigerant recovery control when the predetermined value is reached is provided.

[0020]

In the air conditioner of the first aspect of the present invention, in each indoor unit, it is determined whether the connected device is an outdoor unit or a relay unit. Also, when the operation of each indoor unit is stopped or interrupted,
Refrigerant recovery control for recovering the refrigerant remaining in the indoor unit to the outdoor unit is executed. However, the execution timing of this refrigerant recovery control is uniquely determined for each indoor unit according to the determination result in each indoor unit.

In the air conditioner of the second aspect of the present invention, in each indoor unit, it is determined whether the connected device is an outdoor unit or a relay unit. When the operation of each indoor unit is stopped or interrupted, the refrigerant recovery control for recovering the refrigerant remaining in the indoor unit to the outdoor unit side is executed. However, in each indoor unit, select the unique address defined for the indoor unit or the relay device of the connection destination according to the above determination result, and based on the selected unique address, determine the execution timing of the refrigerant recovery control independently. To do.

In the air conditioner of the third aspect of the present invention, in each indoor unit, it is determined whether the connected device is an outdoor unit or a relay unit. When the operation of each indoor unit is stopped or interrupted, the refrigerant recovery control for recovering the refrigerant remaining in the indoor unit to the outdoor unit side is executed. However, in each indoor unit, if the determination result is an outdoor unit, select the unique address of the indoor unit, and if the determination result is a repeater, select the unique address of the destination relay device and select the unique address. The execution timing of the refrigerant recovery control is uniquely determined based on the address.

In the air conditioner of the fourth aspect of the present invention, in each indoor unit, it is determined whether the connected device is an outdoor unit or a relay unit. When the operation of each indoor unit is stopped or interrupted, the refrigerant recovery control for recovering the refrigerant remaining in the indoor unit to the outdoor unit side is executed. However, in each indoor unit, if the determination result is an outdoor unit, the unique address of the indoor unit is selected, and if the determination result is a relay device, the unique address of the relay destination device is selected. Then, the compressor counts up every predetermined time during the operation of the compressor, and when the count value reaches the predetermined value corresponding to the selected unique address, the refrigerant recovery control is actually started.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, an outdoor unit A includes a variable capacity compressor 1, a four-way valve 2, an outdoor heat exchanger 3, a check valve 4,
It has an expansion valve 5 for heating, a liquid receiver 6, and an accumulator 7.

The indoor units B ₁ , B ₂ , ... B _n have a flow rate adjusting valve 11 using a pulse motor valve (PMV), an indoor heat exchanger 12, and an air temperature sensor 13. The outdoor unit A and the plurality of indoor units B ₁ , B ₂ , ... B _n are directly connected by a refrigerant pipe to form the next heat pump type refrigeration cycle capable of cooling and heating.

An outdoor heat exchanger 3 is connected to a discharge port of the compressor 1 via a four-way valve 2, and the check valve 4 is attached to the outdoor heat exchanger 3.
The liquid receiver 6 is connected via a parallel circuit of the expansion valve 5 and the expansion valve 5.
Each indoor heat exchanger 12 is connected to the liquid receiver 6 via each flow rate adjusting valve 11, and each indoor heat exchanger 12 includes the four-way valve 2
Also, it is connected to the suction port of the compressor 1 via the accumulator 7.

That is, during cooling, the refrigerant discharged from the compressor 1 flows in the direction of the solid line arrow in the figure, and the outdoor heat exchanger 3
Is a condenser, and each indoor heat exchanger 12 functions as an evaporator. At the time of heating, the four-way valve 2 is switched, whereby the refrigerant discharged from the compressor 1 flows in the direction of the broken line arrow in the drawing, each indoor heat exchanger 12 functions as a condenser, and the outdoor heat exchanger 3 functions as an evaporator. To do.

Further, as shown in FIG. 2, the indoor units B ₁ , B ₂ and B ₂ are connected to the outdoor unit A via a pair of signal lines (bus lines) L.
... B _n are directly connected. The outdoor unit A has a control unit 10
, And the control unit 20 is mounted on each of the indoor units B ₁ , B ₂ , ... B _n . Further, the indoor units B ₁ , B ₂ , ...
A remote control type operation device (hereinafter abbreviated as a remote control) R is attached to each _Bn .

A unique address (number) is set for each of the indoor units B ₁ , B ₂ , ... B _n , and the signal line L is connected between the outdoor unit A and each indoor unit based on the unique address. Time-division data transmission / reception is performed.

As a time-division data transmission / reception method, for example, CSMA / CD communication control which is collision detection multiplex transmission is adopted. CSMA / CD is a kind of local area network, carrier sense multiple access / coll
Abbreviation for ision detection.

The control unit 10 of the outdoor unit A has the following functional means. [1] A means for taking in the data sent to the signal line L and determining the priority operation mode (cooling / heating).

[2] Data request command for each indoor unit,
And means for sending the operation data of the outdoor unit to the signal line L at a constant cycle T together with the unique address of the outdoor unit. The operation data includes the content of the determined priority operation mode.

Each of the control units 20 of the indoor units B ₁ , B ₂ , ... B _n has the following functional means. [1] A means for taking in a data request command and operation data sent to the signal line L, and judging the operation state of the entire air conditioner from the operation data.

[2] Means for executing the operation when the operation mode set by the remote controller R matches the priority operation mode determined by the outdoor unit A, and for prohibiting the operation when they do not match. [3] During operation, the difference Δ between the room temperature Ta detected by the room temperature sensor 13 and the set temperature Ts set by the remote controller R.
A means for obtaining T as an air conditioning load.

[4] Means for controlling the opening of the flow rate adjusting valve 11 according to the air conditioning load. When the air conditioning load is zero, the flow rate adjusting valve 11 is fully closed to interrupt the operation. [5] Discriminating means for discriminating whether the device to which the indoor unit is connected is the outdoor unit A or the relay device based on the unique address added to the taken operation data. What is a repeater?
It is used in the refrigeration cycle when multiple indoor units with a relatively small capacity are installed in the same area. It is not used in the refrigeration cycle of FIG.

[6] Control for executing refrigerant recovery control for recovering the refrigerant remaining in the indoor heat exchanger 12 of the indoor unit to the outdoor unit A side when the heating operation is stopped (including prohibition) and interrupted. means.

[7] A means for determining the execution timing of this refrigerant recovery control according to the discrimination result of the discrimination means. Specifically, if the determination result is the outdoor unit A, the unique address of the indoor unit is selected, and if the determination result is the relay unit, the unique address of the relay unit is selected. During the operation of the compressor 1 based on this, a count-up is performed every predetermined time, and when the count value reaches a predetermined value corresponding to the selected unique address, the start of the refrigerant recovery control is determined.

[8] In response to the fetched data request command,
Means for transmitting to the signal line L data indicating the content of the required operation mode based on the operation of the remote controller R and the control operation of the indoor unit at a predetermined timing based on the unique address of the indoor unit.

Next, the operation of the above configuration will be described. As shown in FIG. 3, the outdoor unit A repeatedly sends the data request command and the operation data to the signal line L together with the unique address of the outdoor unit A at a constant cycle T.

When the indoor unit B ₁ , B ₂ , ... B _n fetches the data request command and the operation data sent from the outdoor unit A (YES in step 101), the operation data of the outdoor unit A is used. While grasping the situation, in response to the data request command, the data representing the content of the control operation of the indoor unit is sent to the signal line L at a predetermined timing based on the unique address of the indoor unit (step 102).

Further, the indoor units B ₁ , B ₂ , ... B _n are based on the unique address added to the fetched operation data, whether the device to which the indoor unit is connected is the outdoor unit A or the repeater. Is determined (step 103).

The refrigerating cycle shown in FIG. 1 has no repeater, and the equipment connected to each indoor unit is the outdoor unit A. That is, the determination result is the outdoor unit A. When the determination result is the outdoor unit A (YES in step 104), the unique address (number) of the indoor unit is selected, and the predetermined value C corresponding to the unique address is determined. For example, the number of the unique address is set as the predetermined value C (step 105).

On the other hand, it is judged based on the operation data from the outdoor unit A whether or not the compressor 1 is in operation, and if it is in operation (YES in step 107), the time count t is executed (step 108). When the operation of the compressor 1 is stopped (step
107 NO), clear the time count t (step
109).

When the time count t reaches the predetermined time t ₁ (YES in step 110), the value N of the counter in the controller 20 is incremented by "1" (step 111).
). This count-up is repeated every predetermined time t ₁ .

When the heating operation mode is set (YES in step 112) and the operation of the indoor unit is stopped or interrupted (YES in step 113), the count value N and the predetermined value C are set. Compare (step 114).

When the count value N reaches the predetermined value C (YES in step 114), the count value N is cleared (step 115), and the flow rate adjusting valve 11 in the fully closed state is opened to the predetermined opening for a certain time. .

When the flow rate adjusting valve 11 is opened, suction pressure of the compressor 1 is applied to the indoor heat exchanger 12 through the flow rate adjusting valve 11, and the refrigerant remaining in the indoor heat exchanger 12 is sucked into the outdoor unit 1 side. Be collected and collected.

In this way, by collecting the refrigerant accumulated in the indoor unit that is stopped or suspended, it is possible to eliminate the shortage of the refrigerant circulation amount during the refrigeration cycle, and thus it is possible to obtain sufficient air conditioning capacity in the operating indoor unit. . In addition, a sufficient amount of lubricating oil returns to the compressor 1 as the refrigerant is recovered, and the compressor 1 can be prevented from being locked.

In particular, since the refrigerant recovery control in each indoor unit is independently executed in each indoor unit without requiring a refrigerant recovery command from the outdoor unit A, data transmission / reception control between the outdoor unit A and each indoor unit is performed. It is not necessary to entangle the refrigerant recovery control, and thus the complication of data transmission / reception control can be avoided.

Moreover, since the refrigerant recovery control in each indoor unit is executed in a time-division manner based on the unique address of each indoor unit, the refrigerant is simultaneously distributed to all the indoor units that are stopped or suspended as in the conventional case. The situation of distribution to is eliminated. Therefore, even if the number of indoor units in operation is one and all the remaining indoor units are stopped or interrupted,
A sufficient amount of refrigerant can be made to flow through the indoor unit during operation, and there is no lack of capacity.

Next, the second embodiment of the present invention will be described with reference to FIG.
And FIG. 6 will be described. Here, a cold / warm simultaneous air conditioner is described as an example. Indoor units B ₁ , B
_2, ... B ₅ a relay apparatus D _1, D _2, the outdoor via the D ₃ machine A
To the indoor unit B _n
Is directly connected to the outdoor unit A by a refrigerant pipe and a signal line.

The repeaters D ₁ , D ₂ , D ₃ are the indoor units B ₁ ,
It is for switching the flow direction of the refrigerant to B ₂ , ... B ₅ , and has two two-way valves 14, 15 for switching. The outdoor unit A is also provided with three two-way valves 31, 32, 33 in order to switch the flow direction of the refrigerant to each indoor unit.

The outdoor heat exchanger 3 is connected to the discharge port of the compressor 1 through the two-way valve 31, and the outdoor heat exchanger 3 receives the check valve 4 and the expansion valve 5 through a parallel circuit. Connect the liquid container 6. One end of each indoor heat exchanger 12 is connected to the liquid receiver 6 via each flow rate adjusting valve 11, and the other end of each indoor heat exchanger 12 is connected to the compressor 1 via the two-way valve 15 and the accumulator 7.
Connect to the suction port of.

Regarding the directly connected indoor unit B _n ,
The other end of the indoor heat exchanger 12 is directly connected to the suction port of the compressor 1 for heating only. Each indoor heat exchanger 12 is connected to the discharge port of the compressor 1 via the two-way valve 32 and each two-way valve 14.
Connect the other end of.

The connecting portion between the two-way valve 31 and the outdoor heat exchanger 3 is connected to the suction port of the compressor 1 via the two-way valve 33 and the accumulator 7. On the other hand, the control unit 10 of the outdoor unit A
Has the following functional means.

[1] The data sent from the repeater and the indoor unit to the signal line L is taken in to determine the priority operation mode (cooling / heating), and the two-way valves 31, 32, 33 are operated according to the priority operation mode. Means for controlling opening and closing. In particular,
The number of indoor units requesting cooling is compared with the number of indoor units requesting heating, and the priority operation mode is determined according to the request of the larger one.

[2] A means for sending the data request command to the repeater and the indoor unit and the operation data of the outdoor unit together with the unique address of the outdoor unit to the signal line L at a constant cycle T. The operation data includes the content of the determined priority operation mode.

The control unit 20 for the indoor units B ₁ , B ₂ , ... B _n
Has the following functional means. [1] A means for taking in a data request command and operation data sent to the signal line L, and determining an operation state based on the operation data.

[2] A means for obtaining the difference ΔT between the indoor temperature Ta detected by the indoor temperature sensor 13 and the set temperature Ts set by the remote controller R during operation as an air conditioning load. [3] A means for controlling the opening of the flow rate adjusting valve 11 according to the air conditioning load. When the air conditioning load is zero, the flow rate adjusting valve 11 is fully closed to interrupt the operation.

[4] Discriminating means for discriminating whether the device to which the indoor unit is connected is the outdoor unit A or the repeater D based on the unique address added to the fetched operation data. [5] When the heating operation is stopped (including prohibition) and interrupted,
Control means for executing refrigerant recovery control for recovering the refrigerant remaining in the indoor heat exchanger 12 of the indoor unit to the outdoor unit A side.

[6] A means for determining the execution timing of this refrigerant recovery control according to the discrimination result of the discrimination means. Specifically, if the determination result is the outdoor unit A, the unique address of the indoor unit is selected, and if the determination result is the relay unit D, the unique address of the relay unit is selected. During the operation of the compressor 1 based on, the counter is counted up every predetermined time, and when the count value reaches the predetermined value corresponding to the selected unique address, the start of the refrigerant recovery control is determined.

[7] In response to the fetched data request command,
Means for sending to the signal line L data indicating the required operation mode based on the operation of the remote controller R, the air conditioning load, and the content of the control operation of the indoor unit at a predetermined timing based on the unique address of the indoor unit.

Each of the repeaters D ₁ , D ₂ and D ₃ is equipped with a control unit 30 and has the following functional means. [1] A unit that takes in a data request command and operation data sent from the outdoor unit A to the signal line L, and sends the data request command and the operation data to the signal line L toward the connected indoor unit together with the unique address of the relay device.

[2] Data sent from the connected indoor unit is
Means for transmitting to the signal line L toward the outdoor unit A at a predetermined timing based on the unique address of the repeater. When a plurality of indoor units are connected, the data sequentially sent from each indoor unit is fetched, and the data is collectively sent to one.

[3] Means for judging the required operation mode of each indoor unit based on the data sent from the connected indoor unit and controlling the opening / closing of the two-way valves 14 and 15 according to the judgment result. Next, the operation of the above configuration will be described with reference to FIGS.

As shown in FIG. 3, the outdoor unit A repeatedly sends a data request command and operation data to the signal line L together with the unique address of the outdoor unit A at a constant cycle T. When the relay units D ₁ , D ₂ , D ₃ take in the data request command and the operation data sent from the outdoor unit A, the relay units D ₁ , D ₂ , D ₃ together with the unique addresses of the relay units, the indoor units B ₁ , B ₂ , ... B. _n
To the signal line L. As with the outdoor unit A, the repeater D ₃ connecting a plurality of indoor units repeatedly sends the data request command and the operation data at a constant cycle T.

When the indoor unit B ₁ , B ₂ , ... B _n takes in the data request command and the operation data sent from the outdoor unit A or the repeater D (YES in step 101), the operation data is extracted from the outdoor unit to the outdoor unit. The operation status of the machine A is grasped, and in response to the data request command, the data indicating the content of the control operation of the room is sent to the signal line L at a predetermined timing based on the unique address of the room (step S). 102).

Further, the indoor units B ₁ , B ₂ , ... B _n are based on the unique address added to the fetched operation data, whether the device to which the indoor unit is connected is the outdoor unit A or the repeater. It is determined whether it is D (step 103).

If the determination result is the outdoor unit A, the unique address (number) of the indoor unit is selected, and the predetermined value C corresponding to the unique address is determined. For example, the number of the unique address is set as the predetermined value C (step 105).

If the determination result is the repeater D, the unique address (number) of the repeater D at the connection destination is selected, and the predetermined value C corresponding to the unique address is determined. For example, the number of the unique address is set as the predetermined value C (step 106).

On the other hand, based on the operation data from the outdoor unit A, it is judged whether or not the compressor 1 is in operation, and if it is in operation (YES in step 107), the time count t is executed (step 108). When the operation of the compressor 1 is stopped (step
107 NO), clear the time count t (step
109).

When the time count t reaches the predetermined time t ₁ (YES in step 110), the value N of the counter in the controller 20 is incremented by "1" (step 111).
). This count-up is repeated every predetermined time t ₁ .

When the heating operation mode is set (YES in step 112) and the operation of the indoor unit is stopped or interrupted (YES in step 113), the count value N and the predetermined value C are set. Compare (step 114).

When the count value N reaches the predetermined value C (YES in step 114), the count value N is cleared (step 115), and the flow rate adjusting valve 11 in the fully closed state is opened to the predetermined opening for a certain time. .

When the flow rate adjusting valve 11 is opened, the suction pressure of the compressor 1 is applied to the indoor heat exchanger 12 through the flow rate adjusting valve 11, and the refrigerant remaining in the indoor heat exchanger 12 is sucked into the outdoor unit 1 side. Be collected and collected.

In this way, by collecting the refrigerant accumulated in the stopped or suspended indoor unit, it is possible to solve the shortage of the refrigerant circulation amount during the refrigeration cycle, and thus it is possible to obtain a sufficient air conditioning capacity in the operating indoor unit. . In addition, a sufficient amount of lubricating oil returns to the compressor 1 as the refrigerant is recovered, and the compressor 1 can be prevented from being locked.

In particular, since the refrigerant recovery control in each indoor unit is independently executed in each indoor unit without requiring a refrigerant recovery command from the outdoor unit A, data transmission / reception control between the outdoor unit A and each indoor unit can be performed. It is not necessary to entangle the refrigerant recovery control, and thus the complication of data transmission / reception control can be avoided.

Moreover, since the refrigerant recovery control in each indoor unit is executed in a time-division manner based on the unique address of each indoor unit, the refrigerant is simultaneously distributed to all the indoor units that are stopped or suspended as in the conventional case. The situation of distribution to is eliminated. Therefore, even if the number of indoor units in operation is one and all the remaining indoor units are stopped or interrupted,
A sufficient amount of refrigerant can be made to flow through the indoor unit during operation, and there is no lack of capacity. The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention.

[0079]

As described above, according to the present invention, it is determined in each indoor unit whether the connected device is an outdoor unit or a relay device, and each indoor unit has a timing according to the determination result. Since the refrigerant recovery control is independently executed, the refrigerant accumulated in the indoor unit can be reliably recovered and always operated properly without complicating the data transmission / reception control between the outdoor unit and each indoor unit. An air conditioner with excellent reliability can be provided.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a refrigeration cycle according to a first embodiment.

FIG. 2 is a block diagram of a control circuit according to the first embodiment.

FIG. 3 is a diagram showing a format of data transmission in the first and second embodiments.

FIG. 4 is a flowchart for explaining the operation of the first and second embodiments.

FIG. 5 is a configuration diagram of a refrigeration cycle of a second embodiment.

FIG. 6 is a block diagram of a control circuit according to a second embodiment.

[Explanation of symbols]

A ... outdoor _{unit, B 1, B 2, ...} B n ...... indoor unit, D _1, D
₂ , D ₃ ...... Repeater, R ... Remote control, L ... Signal line, 1 ...
Compressor, 3 ... Outdoor heat exchanger, 10 ... Control part, 11 ... Flow control valve, 12 ... Indoor heat exchanger, 20 ... Control part, 30 ... Control part.

Claims (4)

[Claims] 1. An air conditioner in which one outdoor unit and a plurality of indoor units are directly or via a relay unit connected to a refrigerant pipe and a signal line, and the operation is controlled by transmitting and receiving data through the signal line. In the machine, control means for executing a refrigerant recovery control for recovering the refrigerant remaining in the indoor unit to the outdoor unit side when the operation of each indoor unit is stopped or interrupted, and provided in each indoor unit, A determining unit that determines whether the connected device is an outdoor unit or a relay unit, and a determining unit that determines the execution timing of the refrigerant recovery control according to the determination result of the determining unit. And an air conditioner. 2. The air conditioner according to claim 1, wherein the deciding means selects a unique address defined for the indoor unit or the relay device of the connection destination according to the determination result, and sets the selected unique address to the unique address. Based on the above, a means for deciding the execution timing of the refrigerant recovery control is provided. 3. The air conditioner according to claim 2, wherein the determining means selects the unique address of the indoor unit when the determination result is the outdoor unit, and the connection destination relay unit when the determination result is the relay unit. It is characterized by comprising means for selecting a unique address. 4. The air conditioner according to claim 2 or 3, wherein the determining means counts up every predetermined time during operation of the compressor, and the count value is a predetermined value corresponding to the unique address. And a means for deciding the start of the refrigerant recovery control when the above condition is reached.