JPH027422Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention is an air conditioner normally used in buildings, etc., specifically, it is equipped with an outdoor unit and an indoor unit, and the outdoor unit includes a compressor, a four-way switching valve, and a pneumatic outdoor heat exchanger. The indoor unit is equipped with an air-type indoor heat exchanger and an indoor fan, and heating operation is performed as a heating cycle by switching the four-way switching valve, and when the outdoor heat exchanger is frosted. An air conditioner that performs defrost operation as part of the cooling cycle, and in particular, a control that uses changes in refrigerant pressure in the indoor unit to detect that defrost operation is being performed only on the indoor unit side during defrost operation. Regarding circuits.

Generally, a control circuit for detecting frost on an outdoor heat exchanger, switching the refrigeration cycle to the cooling cycle, and performing defrost operation is used to detect frost on the outdoor heat exchanger,
Since the four-way switching valve and the like are provided in the outdoor unit, they are provided on the outdoor unit side.

On the other hand, since the defrost operation is performed by switching to the cooling cycle, the indoor heat exchanger of the indoor unit becomes an evaporator, and at this time, it is necessary to stop the indoor fan to prevent cold draft, and to replenish the defrost heat source. It is necessary to operate the refrigerant heating heater, which is an auxiliary heater for space heating.

Therefore, when the defrost operation starts and the defrost operation is completed, a defrost operation signal must be sent from the outdoor unit to the indoor unit in response to these operations. As a control circuit for such signal transmission, the one described in Japanese Utility Model Publication No. 56-29623 is known.

Hereinafter, a description will be given based on FIG. 4, which illustrates the main parts of the prior art.

The air conditioner described in the above publication is capable of performing cooling operation in addition to heating operation, so it is equipped with a cooling switch, etc., but the present invention performs heating operation and defrost operation. Therefore, FIG. 4 illustrates the conventional technique without the control circuit for performing the cooling operation.

That is, the outdoor unit U includes a day icer R that detects frost on the outdoor heat exchanger (not shown), closes the defrost switch S when frost occurs, and opens the defrost switch S when there is no frost and when defrost is completed. Furthermore, a normally open contact X ₄ - is connected in series with this de-icer R.
An auxiliary relay X ₄ with 1, X ₄ -2 is connected. In addition, normally open contact X ₄ -2 of auxiliary relay X ₄
and four-way switching valve auxiliary relay _X5 are connected in series. On the other hand, an operation switch RS is connected to the indoor unit V in parallel with an auxiliary relay _X6 for controlling the compressor on/off and an auxiliary relay _X7 for controlling the indoor fan motor. The normally open contact X ₆ -1 of the compressor start/stop control auxiliary relay X ₆ is connected to the outdoor unit U via the connection wiring V ₄ ,
It is also connected to an auxiliary relay X ₃ having normally open contacts X ₃ -1 and X ₃ -2. Further, the normally open contact X ₃ -1 of the auxiliary relay X ₃ is connected in series with the outdoor fan drive motor M ₁ , and the normally open contact X ₃ -2 of the auxiliary relay X ₃ is connected to the compressor drive motor M ₂ . connected in series with.

Further, an auxiliary relay X 1 is provided with a normally open contact X ₄ -1 of an auxiliary relay X ₄ provided in the outdoor unit U and a normally closed contact X ₁ -1 connected by a communication wiring _{V 3} .
A defrost operation detector P is constituted by the normally open contact X ₄ -1, the auxiliary relay X ₁ and the normally closed contact X ₁ -1. And this auxiliary relay
The normally closed contact X ₁ -1 of X ₁ , the normally open contact X ₇ -1 of the indoor fan motor control auxiliary relay X ₇ , and the indoor fan motor auxiliary relay X ₂ are connected in series.

Thus, when the outdoor heat exchanger frosts, the defrost switch S of the de-icer R closes and defrost operation starts, and at the same time, the auxiliary relay _X4 is energized and the normally open contacts _X4-2 and normally open contacts are energized.
X ₄ -1 is closed. This allows four-way switching valve x ₅
At the same time that the auxiliary relay _X1 of the indoor unit V is energized and the normally closed contact _X1-1 is opened, the indoor fan motor _X2 is stopped.

Furthermore, when the defrost of the outdoor heat exchanger is completed, the defrost switch S of the day icer R is opened, the defrost operation is completed, and the heating cycle is switched to.The normally open contact _X4-1 is also opened and the auxiliary relay is activated.
X ₁ is demagnetized, the normally closed contact X ₁ -1 is closed, the indoor fan motor X ₂ is driven, and the heating operation is switched.

As described above, conventionally, the defrost operation _of the outdoor unit U is electrically sent to the indoor unit _V by _the above-mentioned defrost operation detector. contact wiring
In addition to V ₂ and the connection wiring V ₄ for sending signals to drive the compressor and the outdoor fan, the connection wiring for sending defrost operation signals.
I needed _V3 .

The present invention was developed in view of the above problems, and its purpose is to detect when the defrost operation has started only on the indoor unit side, without electrically sending the defrost operation of the outdoor unit to the indoor unit. This is what I am trying to do. In order to achieve this purpose, the configuration of the present invention includes a switch means that senses the refrigerant pressure, detects defrost operation, and opens the unit at a portion where the refrigerant pressure changes in height between the cooling cycle and the heating cycle of the indoor unit. an electrical circuit for the indoor unit, comprising: a defrost operation detector; a switch for operating the defrost operation detector; and a fan motor control circuit for controlling a fan motor of the indoor fan by operating the switch; When the defrost operation is performed in the cooling cycle, that is, when the defrost operation is performed after switching from the heating cycle to the cooling cycle, the refrigerant pressure in the portion changes in level. The defrost operation is detected using the defrost operation, and the fan motor of the indoor fan is controlled by the defrost operation detection signal to stop the indoor fan in order to prevent cold draft. Furthermore, when the defrost operation of the outdoor heat exchanger of the outdoor unit is completed, the system switches to the heating cycle, and the end of the defrost operation is detected by using the pressure change in the above-mentioned part, and this non-defrost operation signal is used to detect the end of the defrost operation. The fan motor of the indoor fan is restarted, and the indoor fan that has been stopped is re-driven to prevent cold draft. Therefore, there is no need to provide communication wiring for the defrost operation signal between the outdoor unit and the indoor unit.

Hereinafter, a first embodiment of the present invention will be described based on FIGS. 1 and 2.

In the first embodiment, for one outdoor unit,
This is a separate type air conditioner to which only one indoor unit is connected, and it does not perform cooling operation but performs heating operation and defrosting operation.

First, the refrigerant circuit will be explained based on FIG.

In Fig. 1, A is an outdoor unit and B is an indoor unit.In outdoor unit A, 1 is a compressor, 2 is a four-way switching valve, 3 is an air-type outdoor heat exchanger, 4 is an outdoor fan, and 5 is an storage unit. ,6
7 is a heating expansion valve, and 7 is a check valve.

In the indoor unit B, 8 is an air-type indoor heat exchanger, 9 is an indoor fan, 10 is an expansion valve for defrost operation, and 11 is a check valve.

12 is a gas pipe connected to one switching port of the four-way switching valve 2, and 12a is a gas pipe connecting the gas pipe 12 and the air-type indoor heat exchanger 8.
13 is a gas pipe connecting another switching port of the four-way switching valve 2 and the air-type outdoor heat exchanger 3. 14 is a liquid pipe connected to the heat exchanger 3, and a parallel circuit of a heating expansion valve 6 and a check valve 7 is interposed therein. 14
A is a liquid pipe connecting the liquid pipe 14 and the indoor heat exchanger 8, and the refrigerant circuit shown in FIG. It works as follows during heating operation. That is, the high-pressure gas refrigerant discharged from the compressor 1 is sent to the indoor heat exchanger 8 through the four-way switching valve 2,
There, it condenses, passes through the check valve 11, is depressurized by the heating expansion valve 6, becomes a low-pressure gas refrigerant in the pneumatic outdoor heat exchanger 3, and is transferred to the compressor again via the four-way selector valve 2 and the accumulator 5. It returns to 1.

In addition, during defrost operation, the high-pressure gas refrigerant discharged from the compressor 1 passes through the four-way switching valve 2, is condensed in the air outdoor heat exchanger 3, and further passes through the check valve 7 for defrost operation. It is depressurized by the expansion valve 10, becomes a low-pressure gas refrigerant in the pneumatic indoor heat exchanger 8, and then returns to the compressor 1 via the four-way selector valve 2 and the accumulator 5.

In addition, the outdoor unit A is equipped with a sensor to detect whether or not the coil (not shown) of the outdoor heat exchanger 3 is frosted during heating.
A frost detector 20a of the de-icer 20 shown in FIG. 2 is provided in the apparatus. Only when frost is deposited on the coil due to the operation of the day icer 20, the four-way selector valve 2 is switched to allow the refrigerant to flow in the opposite direction, that is, as during the cooling cycle, to perform a defrost operation. There is.

Furthermore, in the indoor unit B, there are parts where the refrigerant pressure changes between the cooling cycle and the heating cycle, such as a part where the pressure is low during the cooling cycle and high during the heating cycle, such as the gas pipe 12.
A defrost operation detector 22 that outputs a defrost operation signal and a non-defrost operation signal depending on whether the pressure is low or high is installed in the piped part of the indoor unit B of a, and when the defrost operation is performed, the detector 22 is activated. The defrost operation signal that is output cuts off power to the electric circuit of the indoor fan 9, which is a defrost device to be described later, and stops the indoor fan 9. In this way, cold drafts are prevented.

Next, the electric circuit of the air conditioner shown in FIG. 1 will be explained with reference to FIG. In Figure 2, _l1 and _l2 are power lines, RS is a rotary switch installed in indoor unit B, and _R4-1 and _R4-2 are for outdoor fan drive motor _M1 or compressor drive motor M2 _. Each normally open contact of the electromagnetic switch _R4 , SV, is an auxiliary relay for the four-way switching valve, which switches the four-way switching valve 2 to the cooling cycle side when the relay SV is energized, and to the heating cycle side when not energized. .

20 is a day icer, 21 is a defrost switch provided in the day icer 20, and 22 is the above-mentioned defrost operation detector, which includes a pressure switch 22a that opens and closes, and normally closed contacts R ₆ -1, R ₆ -2.
It consists of an auxiliary relay _R6 with

The set pressure of the pressure switch 22a is a value between the maximum pressure during the defrost operation (cooling cycle) and the minimum pressure during the heating operation (heating cycle) in the gas pipe 12a provided with the detector 22, for example, 10 kg/cm. ² . By doing so, the pressure switch 22a is opened during heating operation and closed during defrost operation. 2
3 is the temperature control switch, R ₃ -1 is the auxiliary relay R ₃
R ₆ -1, R ₆ -2 are the normally closed and normally open contacts of the auxiliary relay R ₆ of the defrost operation detector 22, R ₇ -1 is the normally open contact of the auxiliary relay R ₇ , and then,
Each of these electrical elements will be explained. First, the outdoor unit A side will be explained. Outdoor fan drive motor M ₁ and compressor drive motor M ₂ each have normally open contacts R ₄
-1, R ₄ Connected to the power supply via -2.
Between the power lines l ₁ and l ₂ drawn out from the power source, there is a normally open contact R ₃ -1 and an auxiliary relay for the four-way switching valve.
A series line with the SV and a series line between the defrost switch 21 of the de-icer 20 and the auxiliary relay _R3 are connected in parallel.

Terminal b ₁₁ is connected to the power line l ₁ , and terminal b ₃₁ is connected to the auxiliary relay.
The terminal b41 is connected to the power line _l2 through _R4 , and the terminal _b41 is connected to the power line _l2 . Next, the indoor unit B side will be explained.

Terminals b ₁₂ , b ₃₂ , b ₄₂ on the indoor unit B side are connected to the terminals b ₁₁ , b ₃₁ , b ₄₁ on the outdoor unit A side via respective communication wirings B ₁ , B ₃ , B ₄ .

Indoor fan 9 motor _M3 and indoor fan motor auxiliary relay _R8 's normally open contact _R8-1 and normally closed contact _R6
-1, series line between rotary switch RS and auxiliary relay _R8 , rotary switch
Consists of a series line between RS, temperature regulator 23 and auxiliary relay R ₇ , movable contact C ₂ of pressure switch 22a and auxiliary relay R 6 with normally closed and normally open contacts R ₆ -1, R _{6 -2} . The defrost operation detector 22 is connected between the respective power lines l ₁ and l ₂ wired to the indoor unit B via the respective terminals b ₁₂ and b ₄₂ . Terminal b ₃₂ is connected to the power supply line l ₁ via a normally open contact R ₇ -1.

Next, the operation of the electric circuit shown in FIG. 2 will be explained.

During heating operation, when rotary switch RS is set to heating, auxiliary relay _R8 is energized, and when the room temperature is low, the contacts of temperature controller 23 are closed, auxiliary relay _R7 is energized, and normally open. Contacts R ₈ -1 and R ₇ -1 are closed.

By closing the normally open contact R ₇ -1, the auxiliary relay R ₄ of outdoor unit A is energized, and the normally open contacts R ₄ -1,
Since R ₄ -2 is closed, the operation of the outdoor fan drive motor M ₁ and the compressor drive motor M ₂ is started. On the other hand, the gas pipe 12 of the indoor unit B in which the defrost operation detector 22 is installed
Since pressure inside a is normally low at the time of starting heating operation, the pressure switch 22a of the detector 22
The movable contact _C2 is closed, but after a while after heating starts, the pressure inside the gas pipe 12a becomes higher than the set pressure, and the movable contact _C2 opens, thereby causing the auxiliary relay _R6 to open. is demagnetized and normally closed contact
R ₆ -1 is closed and the detector 22 outputs a non-defrost operation signal. As a result, the operation of the indoor fan 9 is started. By the above operations, indoor heating is started.

Next, defrost operation will be explained.

When the outdoor heat exchanger frosts, the defrost switch 21 of the day icer 20 closes,
Auxiliary relay _R3 is energized. By this,
The four-way switching valve auxiliary relay SV is excited, and the four-way switching valve 2 is switched to the cooling cycle side.

As a result, the pressure in the gas pipe 12a inside the indoor unit B immediately drops below the set pressure of the pressure switch 22a of the defrost operation detector 22. Therefore, the switch 22a is switched, the movable contact _C2 is closed, and the auxiliary relay is closed.
R ₆ is energized. This results in a normally closed contact R ₆ -1
is opened, and the detector 22 outputs a defrost operation signal. As a result, the indoor fan 9 is stopped.

Furthermore, when the defrosting of the outdoor heat exchanger is completed, the defrost switch 21 of the de-icer 20 is turned on.
opens.

As a result, the electric circuit on the outdoor unit A side returns to the heating cycle state again. As a result, the four-way switching valve 2 is switched to the heating cycle side, so that the pressure within the gas pipe 12a of the indoor unit B becomes equal to or higher than the set pressure of the detector 22. Therefore, the detector 22 outputs the non-defrost operation signal again. As a result, the indoor fan 9 is driven again, and indoor heating is restarted.

The above explanation has been given for an example of preventing cold draft during defrost operation, but it is also possible to use defrost equipment to assist the defrost heat source as shown by the broken line in indoor unit B in Fig. 2. A certain heater K may be controlled by the defrost operation signal. That is, the normally open contact R ₆ -2 of the auxiliary relay R ₆ and the heater K
and are connected in series.

Next, as a second embodiment of the present invention, a case where the present invention is used in a separate type air conditioner provided in one outdoor unit A and two indoor units B and C will be described.

The refrigerant circuit of the second embodiment is an indoor unit C (not shown) which has exactly the same refrigerant circuit as the indoor unit B in the refrigerant circuit of the first embodiment shown in FIG.
is connected to outdoor unit A in exactly the same way as indoor unit B. Therefore, since the refrigerant circuit of this embodiment is basically the same as that of the first embodiment, a description thereof will be omitted. Also, since the heating cycle operation and the defrost operation are the same, their effects will be omitted, and only the heating operation using the heating cycle will be explained.
Note that 10 is an expansion valve for cooling.

During cooling operation, the high-pressure gas refrigerant discharged from the compressor 1 passes through the four-way switching valve 2 and is condensed in the pneumatic outdoor heat exchanger 3, as in the defrost operation.
Furthermore, it passes through a check valve 7, is depressurized by an expansion valve 10, and becomes a low-pressure gas refrigerant in an air-type indoor heat exchanger 8.
The air then returns to the compressor 1 via the four-way selector valve 2 and the storage regulator 5.

Next, the electric circuit of the air conditioner of this example is
This will be explained using figures. In Figure 3 l ₁ and l ₂
is the power line, RS is the rotary switch installed in indoor unit B, SW is the air conditioning/heating selector switch installed in outdoor unit A, and MC ₁ -1 is the normally open contact of electromagnetic switch MC ₁ for outdoor fan drive motor M ₁ . , MC ₂ -1 is the normally open contact of the electromagnetic switch MC ₂ for the compressor drive motor M ₂ , SV is the auxiliary relay for the four-way switching valve, and when the relay SV is energized, the four-way switching valve 2 is switched to the cooling side. Switches to the heating side when power is not applied to the heating side.

20 is a de-icer, TR and 21 are a timer and defrost switch respectively provided in the de-icer 20, and 22 is the defrost operation detector described above. 22a is the detector 22
The set pressure of the switch 22a is determined by the pressure switch provided in the gas pipe 1 in which the detector 22 is installed.
The value is set to be between the maximum pressure during defrosting and the minimum pressure during heating operation in 2a, for example, 10 kg/cm ² . By doing this, it turns on during heating operation.
Therefore, it is turned off during defrost operation. 23 is a temperature control switch, R ₁ -1 is a normally closed contact of auxiliary relay R ₁ , R ₁ -2, R ₁ -3 and
_R1-4 is the normally open contact of the relay _R1 , _R2-1 is the normally closed contact of the auxiliary relay _R2 , and _R3-1 is the normally closed contact of the auxiliary relay _R3.
R ₄ -1 is the normally open contact of the auxiliary relay R ₄ ,
R ₅ -1 is the air conditioning/heating switch on the indoor side, R ₆ -1
is the normally closed contact of auxiliary relay R ₆ provided in the defrost operation detector 22, R ₇ -1 is the normally open contact of auxiliary relay R ₇ , and R ₈ -1 and R ₈ -2 are the auxiliary relay R ₈
normally open contacts, R ₉ -1 and R ₉ -2 are auxiliary relays R ₉
The normally open contact of R ₁₀ -1 is the normally open contact of the auxiliary relay R ₁₀ . Next, each of these electrical elements will be explained. First, the indoor unit A side will be explained.
The outdoor fan drive motor M ₁ and the compressor drive motor M ₂ are connected to a three-phase power source via normally open contacts MC ₁ -1 and MC ₂ -1. Between the power lines l ₁ and l ₂ drawn out from the power source, there is a series line between the heating and cooling changeover switch SW and the auxiliary relay R ₁ , and a normally open contact.
Parallel circuit of R ₃ -1 and normally closed contact R ₁ -1 and series line with auxiliary relay SV for four-way switching valve, normally open contact R ₄
Series line between -1 and electromagnetic switch MC ₂ , and normally open contact R ₁₀ -1 and normally open contact R ₁ -2 and timer TR
The series lines with are connected in parallel. Further, the contact of the normally open contact R ₄ -1 on the electromagnetic switch MC ₂ side and the normally open contact R ₁ -2 of the normally open contact R ₁₀ -1
The contacts on the side are connected. One end of the series line between the normally closed contact R ₂ -1 and the electromagnetic switch MC ₁ is the normally open contact R ₁₀
-1 and the normally open contact R ₁ is connected to the connection line with -2,
The other end is connected to the power line _L2 . The movable contact _C3 of the defrost switch 21 is connected to the connection line between the normally open contact _R1-2 and the timer TR. Moreover, the normally open contact _a3 is connected to the parallel circuit of the auxiliary relay _R2 and the auxiliary relay _R3 . The other end of the parallel circuit is connected to the power line _l2 .

Terminal b ₁₁ is connected to the power line l ₁ , terminal b ₂₁ is connected to the normally open contact R ₁ −
3 to the power line L ₁ , and terminal B ₃₁ is the auxiliary relay
The terminal b41 is connected to the power line _l2 through _R4 , and the terminal _b41 is connected to the power line _l2 . (Note that C ₁₁ , C ₁₂ , C ₁₃ , and C ₁₄ are connection terminals for indoor unit C.) Next, the indoor unit B side will be explained.

Terminals b ₁₂ , b ₂₂ , b ₃₂ , b ₄₂ on the indoor unit B side are connected to the terminals b ₁₁ , b ₂₁ , b ₃₁ on the outdoor unit A side via respective connection wirings B ₁ , B ₂ , B ₃ , B ₄ . , b ₄₁ respectively.

Normally open contacts that are the control circuit 24 of the indoor fan 9
The series line between R ₈ -2, normally closed contact R ₆ -1 and indoor fan motor drive motor M ₃ , and the series line between rotary switch RS and auxiliary relay R ₆ are each terminal.
It is connected between each power supply line l ₁ and l ₂ wired to indoor unit B via b ₁₂ and b ₂₂ . Terminal b ₃₂ is connected to the power supply line l ₁ via a normally open contact R ₇ -1. The series line between the normally open contact _R9-2 and the auxiliary relay _R5 has one end on the contact _R9-2 side connected to the terminal _b22 , and the other end connected to the power line _l2 . The movable contact _C2 of the pressure switch 22a is connected to the power line _l2 via an auxiliary relay _R6 . Normally open contact a ₂ of the pressure switch 22a
is connected to the connection line between the normally open contact _R9-2 and the auxiliary relay _R5 . Movable contact of temperature regulator 23
C ₁ is connected to the power supply line l ₁ via a normally open contact R ₉ -1. The low-temperature side contact b ₁ of the regulator 23 is connected to the normally open contact a ₄ of the indoor heating/cooling switch R ₅ -1, and
The high temperature side contact _a1 is the normally closed contact of the switch _R5-1 .
Connected to b ₄ . The movable contact _C4 of the switch _R5-1 is connected to the power line _l2 via an auxiliary relay _R7 . The auxiliary relay _R9 is interposed in the connection line between the power line _l2 and the rotary switch RS.

Next, the operation of the electric circuit shown in FIG. 2 will be explained.

During heating operation, set the rotary switch RS to temperature control, and turn on the air conditioning/heating selector switch SW in outdoor unit A. When the switch RS is set to temperature control, auxiliary relay _R8 and auxiliary relay _R9 are energized, and the normally open contacts _R8-2 , _R9-1 and _{R9 are} energized.
-2 is turned on. Also, turn on the switch SW.
, auxiliary relay R ₁ is energized and the normally open contact
R ₁ -2 and R ₁ -3 are turned ON, and the normally closed contact R ₁
-1 is OFF. This allows the auxiliary relay R ₅
is energized, and the indoor air conditioning/heating selector switch R ₅ −
1 movable contact C ₄ and heating side contact A ₄ are connected.

On the other hand, since the room temperature is usually low at the start of the heating operation, the movable contact C ₁ of the indoor temperature controller 23 is connected to the low temperature side contact b ₁ . Therefore auxiliary relay R ₇
is excited, and the normally open contact R ₇ -1 turns ON. This energizes the auxiliary relay R ₄ , which makes the normally open contact
Since R ₄ -1 is turned ON, each electromagnetic switch MC ₁ ,
MC ₂ is excited, and the outdoor fan drive motor M ₁ and compressor drive motor M ₂ start operating. At the same time, the timer TR is energized and the day icer 20 starts operating.

On the other hand, since the gas pipe 12a of the indoor unit B in which the defrost operation detector 22 is installed is normally at a low pressure at the time of starting the heating operation, the movable contact C of the pressure switch 22a of the detector 22 is closed. ₂ is connected to low voltage side contact A ₂ ,
After a while after heating starts, the pressure inside the gas pipe 12a exceeds the set pressure and the movable contact _C2
is connected to the high voltage side contact _b2 . This demagnetizes the auxiliary relay R ₆ and normally closed contact R ₆ -1
turns ON, and the detector 22 outputs a non-defrost signal. As a result, the control circuit 24 is closed and the operation of the indoor fan 9 is started. By the above operations, indoor heating is started.

Next, defrost operation will be explained.

By the switching operation of the defrost switch 21 of the de-icer 20, the movable contact _C3 is connected to the normally open contact _A3 , and the auxiliary relays _R2 and _R3 are energized.

As a result, the normally closed contact R ₂ -1 is turned OFF, the electromagnetic switch MC ₁ is demagnetized, the outdoor fan 4 is stopped, and the four-way switching valve auxiliary relay SV is energized, and the four-way switching valve 2 is switched to the cooling operation side.

As a result, the gas pipe 12 in indoor unit B
The pressure at a immediately drops below the set pressure of the pressure switch 22a of the defrost operation detector 22. Therefore, the switch 22a is operated to connect the movable contact _C2 and the low voltage side contact _A2 , and the auxiliary relay _R6 is energized. As a result, the normally closed contact R ₆ -1 turns OFF, and the detector 22 outputs a defrost signal, and as a result,
Power to the control circuit 24 is cut off, and the indoor fan 9
will be stopped.

Further, the day icer 20 switches the defrost switch 2 after a certain period of time has passed after starting the defrost operation.
1 to connect the movable contact _C3 to the normally closed contact _B3 . As a result, the electric circuit on the outdoor unit A side returns to the heating operation state again. As a result, the four-way switching valve 2 is switched to the heating side, so that the pressure inside the gas pipe 12a of the indoor unit B becomes equal to or higher than the set pressure of the detector 22.

Therefore, the detector 22 outputs the non-defrost signal again. As a result, the control circuit 24 is energized, the indoor fan 9 is driven again, and indoor heating is resumed.

As described above, according to the embodiment of the present invention, each gas pipe 12a of each indoor unit B, C is provided with a defrost operation detector 22, and the detector 22 detects the defrost operation during heating in the gas pipe 12a. and the detector 22
The control circuit 24 of the indoor fan 9 is de-energized by the defrost operation signal output by the defrost operation signal, and the fan 9 is stopped. For example, cold drafts during heating can be prevented without the need to provide communication wiring for sending defrost signals between the two.

As described above, the present invention is equipped with a switch means that senses the refrigerant pressure, detects defrost operation, and operates to open the indoor unit B at a portion where the refrigerant pressure changes in height during the cooling cycle and during the heating cycle. The defrost operation detector 22 is provided, and the defrost operation detector 22 is operated by an operation switch RS, and a fan motor control circuit for controlling the fan motor _M3 of the indoor fan 9 by operating the switch RS. The detector 22 installed in the indoor units B and C is installed in the fan motor control circuit in the electric circuit of the indoor unit B, and the detector 22 installed in the indoor units B and C allows only the indoor unit to know when the defrost operation has started and finished. Since the defrost operation signal is detected, there is no need to provide communication wiring between the outdoor unit A and each of the indoor units B and C for sending a defrost operation signal, unlike in the conventional case. Therefore, the number of connecting wires between outdoor unit A and indoor units B and C required for installing this type of air conditioner can be reduced by one, reducing installation work and reducing costs. It can be made lower.

[Brief explanation of drawings]

Figure 1 is a refrigerant circuit diagram of an air conditioner according to an embodiment of the present invention, Figure 2 is an electrical circuit diagram of the air conditioner of Figure 1, and Figure 3 is an air conditioner circuit diagram of another embodiment of the present invention. Electrical circuit diagram of conditioner; FIG. 4 is an electric circuit diagram of a conventional air conditioner. 1...Compressor, 2...Four-way switching valve, 8...Pneumatic indoor heat exchanger, 9...Indoor fan, 20...Day icer, 22...Defrost operation detector,
SW...Air conditioning/heating selector switch, RS...Rotary switch, _M3 ...Indoor fan drive motor.

Claims (1)

[Scope of utility model registration request] It is equipped with an outdoor unit A and an indoor unit B, and the outdoor unit A is equipped with a compressor 1, a four-way switching valve 2,
The indoor unit B is equipped with an air-type outdoor heat exchanger 3 and an outdoor fan 4, and the air-type indoor heat exchanger 8 is installed in the indoor unit B.
and an indoor fan 9, and performs heating operation as a heating cycle by switching the four-way switching valve 2, and performs a defrost operation as a cooling cycle when the outdoor heat exchanger 3 is frosted. A defrost operation detector 22 equipped with a switch means that senses the refrigerant pressure, detects the defrost operation, and operates to open the defrost operation is provided at a portion of the unit B where the refrigerant pressure changes in height between the cooling cycle and the heating cycle. The switching means of this defrost operation detector 22 is turned into an operation switch.
It is characterized in that it is interposed in the fan motor control circuit in the electric circuit of the indoor unit B, which includes an RS and a fan motor control circuit that controls the fan motor _M3 of the indoor fan 9 by operating the switch RS. Air conditioner.