IVT AE-X12GR-N User manual

SERVICE MANUAL
Parts marked with " " are important for maintaining the safety of the set. Be sure to replace these parts with specified ones for maintaining the
safety and performance of the set.
This document has been published to be used for
after sales service only.
The contents are subject to change without notice.
CHAPTER 1. SPECIFICATION
[1] SPECIFICATION............................................ 1-1
[2] EXTERNAL DIMENSION............................... 1-2
[3] WIRING DIAGRM .......................................... 1-3
[4] ELECTRICAL PARTS .................................... 1-3
CHAPTER 2. EXPLAMATION OF CIRCUIT AND OP-
ERATION
[1] BLOCK DIAGRAMS....................................... 2-1
[2] MICROCOMPUTER CONTROL SYSTEM........ 2-3
[3] FUNCTION..................................................... 2-8
CHAPTER 3. FUNCTION AND OPERATION OF PRO-
TECTIVE PROCEDURES
[1] PROTECTION DEVICE FUNCTIONS AND
OPERATIONS................................................ 3-1
[2] AIR CONDITIONER OPERATION IN
THERMISTOR ERROR ................................. 3-3
[3] THERMISTOR TEMPERATURE CHAR-
ACTERISTICS ............................................... 3-5
[4] HOW TO OPERATE THE OUTDOOR
UNIT INDEPENDENTLY................................ 3-5
[5] GENERAL TROUBLESHOOTING CHART........ 3-6
[6] MALFUNCTION (PARTS) CHECK METH-
OD .................................................................3-8
[7] OUTDOOR UNIT CHECK METHOD...........3-10
[8] TROUBLESHOOTING GUIDE ....................3-13
CHAPTER 4. REFRIGERATION CYCLE
[1] FLOW FOW REFRIGERANT ........................4-1
[2] STANDARD CONDITION ..............................4-1
[3] TEMPERATURE AT EACH PART AND
PRESSURE IN 3-WAY VALVE ......................4-1
[4] PERFORMANCE CURVES...........................4-2
CHAPTER 5. DISASSEMBLING PROCEDURE
[1] DISASSEMBLY OF INDOOR UNIT...............5-1
[2] DISASSEMBLY OF OUTDOOR UNIT...........5-7
Parts Guide
TopPage
CONTENTS
SPLIT TYPE
ROOM AIR CONDITIONER
INDOOR UNIT
AY-XP12GR-N
OUTDOOR UNIT
AE-X12GR-N
MODELS
In the interests of user-safety (Required by safety regulations in some
countries) the set should be restored to its original condition and only
parts identical to those specified should be used.

AEX12GRN
1 – 1
AEX12GRN Service Manual
CHAPTER 1. SPECIFICATION
[1] SPECIFICATION
1. AY-XP12GR-N – AE-X12GR-N
NOTE: The condition of star”✩” marked item are ‘ISO5151’ : 1994(E), contition T1.
MODEL INDOOR UNIT OUTDOOR UNIT
ITEMS AY-XP12GR-N AE-X12GR-N
Cooling capacity(Min.–Max.) kW 3.5 (0.9 - 4.0)
Heating capacity(Min.– Max.) kW 4.6 (0.9 - 6.5)
Moisture removal(at cooling) Liters/h 1.1
Electrical data
Phase Single
Rated frequency Hz 50
Rated voltage V 220–240
Rated current ✩
(Min - Max.)
Cool A 4.2 ( 0.8 –5.7 )
Heat A 5.3 ( 0.8 –7.8 )
Rated input ✩
(Min - Max.)
Cool W 875 (150–1250 )
Heat W 1150 ( 160–1700 )
Power factor ✩Cool % 95–87
Heat % 99–90
Compressor Type Hermetically sealed rotary type
Model DA111A1F22F
Oil charge 450mL Ester oil VG74
Refrigerant system Evaporator Louver Fin and Grooved tube type
Condenser Corrugate Fin and Grooved tube type
Control Expansion valve
Refrigerant (R410A) 1050g
De-lce system Micro computer controled reversed systems
Noise level
(at cooling/heating)
High dB(A) 40/44 47/49
Low dB(A) 38/38 –
Soft dB(A) 27/34 –
Fan system
Drive Direct drive
Air flow quantity
(at cooling/heating)
High m3/min. 10.5/12.9 32/30
Low m3/min. 9.5/10.3 –
Soft m3/min. 5.9/8.7 –
Fan Cross flow fan Propeller fan
Connections
Refrigerant coupling Flare type
Refrigerant tube size Gas, Liquid 1/2", 1/4"
Drain piping mm O.D φ18
Others
Safety device Compressor: Thermal protector
Fan motors: Thermal fuse
Fuse, Micro computer control
Air filters Polypropylene net (Washable)
Net dimensions Width mm 790 780
Height mm 278 540
Depth mm 198 265
Net weight kg 10 39

AEX12GRN
1 – 2
[2] EXTERNAL DIMENSION
1. Indoor unit
2. Outdoor unit
278
198790
22.0
58 18.5
175
INVERTER AIR CONDITIONER
265
780
540
14
165
540
299
72
58
37.5
12
4.5
324
135
81
136

AEX12GRN
1 – 3
[3] WIRING DIAGRM
1. Indoor unit
2. Outdoor unit
[4] ELECTRICAL PARTS
1. Indoor unit
2. Outdoor Unit
DESCRIPTION MODEL REMARKS
Indoor fan motor MLB084 DC Motor
Indoor fan motor capacitor – –
Transformer – –
FUSE1 – QFS-GA062JBZZ (250V, 3.15A)
FUSE2 – QFS-GA063JBZZ (250V, 2A)
DESCRIPTION MODEL REMARKS
Compressor DA111A1F22F D.C. brush-less motor
Outdoor fan motor ML-A902 DC Motor
Outdoor fan motor capacitor – –
Fu4 – QFS-GA064JBZZ(250V, 1A)
Fu3 – QFS-GA051JBZZ(250V, 2A)
Fu2 – QFS-GA052JBZZ(250V, 3.15A)
Fu1 – QFS-CA001JBZZ(250V, 20A)
Fu5, 6 – QFS-CA002JBZZ(250V, 15A)

AEX12GRN
2 – 1
AEX12GRN Service Manual
CHAPTER 2. EXPLAMATION OF CIRCUIT AND OPERATION
[1] BLOCK DIAGRAMS
1. Indoor unit
Louvre motor drive circuit(upper)
Louvre motor drive circuit(lower)
LED drive circuit
Flow direction control (louver motor upper)
Flow direction control (louver motor lower)
LED display
AC power
Rectification circuit
CPU
Sub
CPU
3.15A
Fuse
Serial signals
2A
Fuse
DC power supply circuit
Fan motor PWM control circuit
Rotation pulse input circuit
AC clock circuit
Remote controller signal reception circuit
Buzzer drive circuit
CPU reset circuit
CPU oscillator circuit
Room temp. detect circuit
Heat exchanger pipe thermo circuit
EEPROM
Select circuit
Serial I/O circuit
Power supply relay drive circuit
Auto restart circuit
Test run circuit
Auxiliary mode
Power on circuit
Cluster generator drive circuit
Indoor fan motor
Fan motor pulse detect
Wireless remote control operation
Audible operation confirmation
Room temp. thermistor
Heat exchanger pipe thermistor
Louvre angle, fan speed
Wireless, preheat, Model select
Indoor/outdoor control signal I/O
Outdoor unit power supply on/off control
Test run (forced operation)
Auxiliary mode button ON/OFF
Self diagnostics, fault diagnosis
Cluster generator
Unit-unit wiring
(AC power and
serial signals)

AEX12GRN
2 – 2
2. Outdoor unit
CPU
20A
protection
15A
protection
Expansion valve drive circuit Expansion valve
Suction temp. thermo. circuit Suction pipe thermistor
2-way valve temp. thermo. circuit 2-way valve thermistor
3.15A
protection
15A
protection
Power supply circuit
CPU oscillator circuit
DC overvoltage detection circuit
Outdoor fan drive circuit
4-way valve relay drive circuit
Power transistor module drive circuit
Serial I/O circuit
CPU reset circuit
Position detection circuit
AC overcurrent detection circuit
Compressor thermo circuit
Heat exchanger pipe thermo circuit
Outdoor temp. thermo. circuit
LED drive circuit
Test mode circuit
Power factor
converter circuit
Filter
circuit
Smoothing
circuit
Pulse amplitube modulation circuit
EEPROM
AC clock circuit
DC overcurrent detection circuit
IGBT
Unit-unit wiring (AC power
and serial signals)
Outdoor fan
4-way valve
Power transistor module
Compressor
Current transformer
Compressor thermistor
Heat exchanger pipe thermistor
Outdoor temperature thermistor
LED

AEX12GRN
2 – 3
[2] MICROCOMPUTER CONTROL SYSTEM
1. Indoor unit
1.1. Electronic control circuit diagram
0.1μ
C 50V
JPF
54 21 54 21
4.7K
RN
2.4K
5V
10.0KF
R96
JPT
9
10 11 12
CIRCUIT DIAGRAM
DISPLAY PWB
LOUVER MOTOR
TOP
LOUVER MOTOR
BOTTOM
DRAIN PAN ASS'Y
MOTOR
FAN
DC
AUX.
SW1
(TEST RUN)
PIPE THERMO
TEMP THERMO
POWER ON
10K
R52
(HA CIRCUIT)
AUTO RESTART
PREHEAT
WIRELESS
HOT KEEP
FLASH
TEST
SUB MICRO COMPUTER PWB
RECEIVER PWB 7-SEGLED&
REMOTE CONTROLLER
SIGNAL
SERIAL SIGNALS
OF SERIAL
ERROR SIGNAL
SUB MICRO COMPUTER
POWER SUPPLY OF
12V LINE
GND for
GND for
5V LINE
CONNECTOR OF JOINT
(DRAIN PAN)
CONNECTOR OF JOINT
(FAN MOTOR)
33
9876
10
12345
8
R41 56k
5V
23
14
32
R38 100k
C18 35V100μ
R39
ZD2HZ24-2
41
4.7k
D1N60
D7
R37RD
4
2 1
30.1μ
C42 25V 12V R44
1.8k 1/4W
C21
16V47μ
R70
Q3
KRC108S
4.7k
4.7k
(SERIAL I/O CIRCUIT)
KRA101S
Q11
5V
5V JPH
R53
JPO
10K
AC CLOCK
25V
R90
R55
FU1
3.15A - 250V
C57
R85
10K
50V
1000p
C20 250V0.01μ
5V
JPS
470μ D2S6M
MQ
R27
10K
10k
R71
1k
1k
R33
6.8k
8.2k
680
PC5
R34
6.8k
89
5V
12V
8 7 6 5 4 3 2 1
8 6
7 5
43 21
1 3 5 7 9
2 4 6 8
10
11 12
1 3
5V
Vs
Vcc
PG
GND
Vm
3 1 2 5 77
5 2 1 33
1 2 5 7
PC3
BCN5
BCN1
PC81716P
1210 11
123456789
987654321
1110 12 10 11
123456789
987654321
1110
7654321
BCN7
KRC102S
Q15
PC1 PC817XP3
C16 50V
0.01μ
10K
R16
275V
0.01μ
C23
2.7K
RHRE
R76 100
1W
SSR
12V
2W
11K
2W
11K
PC2 PC853HXP
2W
680
680
2W
2W
680680
2W
2W
680
D8
D1N60 RG R40RBRC RA
C14 275V 0.1μ
NF1
NR1
200K 200K
39K
D3
D1N60
1/2W
R26 1/2W
R25
R24
C45 275V 0.1μ
E
250V4700p
C53~C56
C54C53
C56
C55
CN80 1234
BUSY
7 6 5 4 3 2 1 8
VPP VCC SCL SDA OE RESET
9VSS
5V
3 2 1
C90
HAJP
4
CN90 R92
R91
100k
R93
1000p
50V
5V
5V
100μ
C3
50V
R95
4.7K
R69
100K
R68
4.7K
100μ
DC15V
D2SBA60
5V
C24
25V
0.1μ
R46
DB1
C1
3.3
450V 120μ
1M
R2
RF
1/2W
1M 1/2W
4 32
1
5V
PC817XP3
3.3K
R66
100K
R73
35V
C46
25V
C50
0.1μ
0.1μ
50V
C47
R28
R31 56k
2A - 250V
14
23 14
5V
FU2
5W
R1
47k
R67
10k
R50
0.1μ
C52 25V C37
0.1μ
25V
5V
JPW JPP
R87 R86
10K 10K
C26
4.7μ
IC2
RESET
0V
ZD1
ST03D - 200
5V
1/4W
100
R56
1/4W
100
R51
C39
16V
0.01μ
C36
0.01μ
16V
10K
10K
10K
CN4
R58 R54 R59
10.0KF
16V10μ
C31
R61
16V10μ
C30
R60
3 4
TH1
1 2
TH2
32
1
5V
2 1
4 3
D1FS4
0.1μ
50V
C4 C44
220μ
10V
C7
470μ
10V
25V C43
12V
IC9
10μH
L1
D14
D1
TR1
6 5 4 3 2 1
4
3
4
1
2
IC10
8
7
6
5
EEPROM
R97
5V
R47
3
3.3k
2
R29
PC4 R32
C17
0.01μ
16V
IC1
64
63
62
61
60
59
58
57
56
55
54
53
52
51
50
49P37
P36
P35
P34
P33
P32
P31
P30
VCC
VR
VSS
P67
P66
P65
P64
P63
P00 P01 P02 P03 P04 P05 P06 P07 P10 P11 P12 P13 P14 P15 P16 P17 33
48 47 46 45 44 43 42 41 40 39 38 37 36 35 34
P20
P21
P22
P23
P24
P25
P26
P27
VSS
XOU
XIN
P40
P41
RST
VSS
P42
20
21
22
23
24
25
26
27
28
29
30
31
32
19
18
17
P43 P44 P45 P46 P47 P50 P51 P52 P53 P54 P55 P56 P57 P60 P61 P62
16
1 2 3 4
15 14 13 12 11 10
9 8 7 6 5
R35 10k
5V
R36
C22
PC817XP3
R30
16V
0.01μ
4.7K
1000p
50V C32
5V
KRC102S
Q19
C25
10V
100μ
C27 16V
0.01μ 4.7k
R45
R94
5V
10k R48
C33
13
2
OSC1
8MHz
KRC108S
Q1
10.0KF
1
N
1 3 6 5
N S
3
2
1
5 6
CNA
3 112V
IN
RY1
(CLUSTER)
CONNECTOR OF JOINT
OUT
N
1
2
R19 1/2W 470K
R19A 1/2W 470K
3W
11K 3W
11K
C98
C99
1KV 1000p
C98, C99
KID65004AF
12V
C19 50V0.047μ
IC6
BZ
GENERATOR
CLUSTER
4.7K
33p
2KV
RM
1500p
10KF
15V
100pF
15KF
1.5K
R10
10000p
MR1712
680
PC817XP3
PC9
4.7K R4
3.3K
R75
910
1/4W
R20
1/4W
R23 910
R22 R3
R65
R5
ZD5
C12
50V
C5 50V
C2
100μ
D2
D1FL20U
D1FL20U
C35
IC3
1 2
5 3
4
R7
1000p
50V
C40
10K
D1FL20U
D15
D21
KRA106S
IC7
R57
D20
D1FL20U
Q9
PC817XP3
1K
R81
2.4KF
R8
2.4KF
R11
R80
PC6
1K R9
PC817XP3
R6
100K
PC817XP3
R13
100K
PJ431CT
250V
C48
PC6 PC7
R17 1K
R98
4.7K
R89
1K
100V
1.2K
C49
11KF
30KF
L2
KIA7815API
1SR139
D

AEX12GRN
2 – 4
1.2. Display circuit diagram
12V
KID65004AF
M5V
M5V
M5V
M5V
7 6 5 4 3 2 1
10 11
1 2 3 4 5 6 7 8 9
12V
12V
5V
KID65004AF
CN103 CN102
IC105 IC106
CN101
IC104
13
28MHz
P30 19 P31 20 P32 21 P33 22 P34 23 P35 24 P36 25 P37 26 P00 27 P01 28 P02 29 P03 30 P04 31 P05 32 P06 33 P07 34 P10 35 P11 36
Vss18 Xout17
16
1 2 3 4
15 14 13 12 11 10
9 8 7 6 5
P12 P13 P14 P20 P21 P22 P23 P24 P25 P26 P27 Vref RESET CNVss Vcc Xin
IC101
M37542
OSC101
0.1μ
25V
C101
C102
4.7μ
IC102
0.1μ
25V C103
C104 16V
47μ
IC103
KID65783AF
R101 R102 R103 R104 R105 R106 R107
1W180 * 7
FLASH
4.7K
R115
4.7K R108
R118 10K R116
100K
KRA106S
KRC106S
KRA106S
R109
R113
R110
R114
1/4W 1.2K*4
LED LED LED LED LED LED LED LED
LED
LEDLED
101 102 103 104 105 106 107 108 109 110
PC
CN105A
CN104B CN104A
a b c d e f g
SG201
Q102Q101
Q104
KRC106S
Q103
CN105B
CN105C
1 2 3
25V
R201
47
IC201
RECEIVER CIRCUIT
SUB MICRO COMPUTER PWB
CIRCUIT DAIGRAM
1 2 3 4 5
LOUVER MOTOR
BOTTOM
LOUVER MOTOR
TOP
SERIAL SIGNALS
REMOTE CONTROLLER
SIGNALS
ERROR SIGNAL
OF SERIAL
POWER SUPPLY OF SUB MICRO COMPUTER
5V LINE
GND for 12V LINE GND for
7 - SEG LED & RECEIVER PWB
GND for 12V LINE
GND for
5V LINE
12V LINE GND for
12V LINE GND for
GND for 12V LINE 12V LINE GND for
JP1
GND for
5V LINE
DISPLAY PWB
()
B L U E
SIGNALS
REMOTE CONTROLLER
GP1U261RK
111B
(COM) 5
(COM) 10
7 (A1)
6 (B1)
4(C1)
1(D1)
3 (E1)
8 (F1)
9 (G1)
2 (H1)
7 (A2)
6 (B2)
4(C2)
1(D2)
3 (E2)
8 (F2)
9 (G2)
2 (H2)
c d e f g
JP2
0.22μ
50V C105
KRC106S
Q105
1K
5V
R119
25V
C202
47μ
16V
C201
0.1μ
+
C2
C1
H2
H1
B2B1 F2
F1
E2
E1 D2
D1
G2G1
A2
A1
a
b
c
d
e
f
g
g
f
e
d
c
b
a
RESET
9 8 7 6 5 4 3 2 1
12 11 1010
11 12
1 2 3 4 5 6 7 8 9
10
9 8 7 6 5 4 3 2 1
5432112345
KID65004AF
12V 12V
8
7
6
5
4
3
2
1
9
1 2 3 4 5 6 7 8
12V
5V

AEX12GRN
2 – 5
1.3. Printed wiring board

AEX12GRN
2 – 6
2. Outdoor unit
2.1. Electronic control circuit diagram

AEX12GRN
2 – 7
2.2. Printed wiring board

AEX12GRN
2 – 8
[3] FUNCTION
1. Function
1.1. Startup control
The main relay remains off during the first 45 seconds (first safety
time) immediately after the power cord is plugged into an AC outlet in
order to disable outdoor unit operation and protect outdoor unit electric
components.
1.2. Restart control
Once the compressor stops operating, it will not restart for 180 sec-
onds to protect the compressor.
Therefore, if the operating compressor is shut down from the remote
control and then turned back on immediately after, the compressor will
restart after a preset delay time.
(The indoor unit will restart operation immediately after the ON switch
is operated on the remote control.)
1.3. Cold air prevention control
When the air conditioner starts up in heating mode, the indoor unit fan
will not operate until the temperature of the indoor unit heat exchanger
reaches about 23°C in order to prevent cold air from blowing into the
room.
Also, the indoor unit fan operates at low speed until the temperature of
the indoor unit heat exchanger reaches about 38°C so that people in
the room will not feel chilly air flow.
1.4. Odor prevention control
When the air conditioner starts up in cooling mode, the discharged air
temperature is lowered slightly, and for the reduction of unpleasant
odors the operation of the indoor unit fan is delayed 60 seconds if the
automatic fan speed mode in cooling mode is set.
1.5. Indoor unit heat exchanger freeze prevention control
If the temperature of the indoor unit heat exchanger remains below
0°C for 4 consecutive minutes during cooling or dehumidifying opera-
tion, the compressor operation stops temporarily in order to prevent
freezing.
When the temperature of the indoor unit heat exchanger rises to 2°C
or higher after about 180 seconds, the compressor restarts and
resumes normal operation.
1.6. Outdoor unit 2-way valve freeze prevention control
If the temperature of the outdoor unit 2-way valve remains below 0°C
for 10 consecutive minutes during cooling or dehumidifying operation,
the compressor operation stops temporarily in order to prevent freez-
ing.
When the temperature of the 2-way valve rises to 10°C or higher after
about 180 seconds, the compressor restarts and resumes normal
operation.
1.7. Indoor unit overheat prevention control
During heating operation, if the temperature of the indoor unit heat
exchanger exceeds the indoor unit heat exchanger overheat preven-
tion temperature (about 45 to 54°C) which is determined by the operat-
ing frequency and operating status, the operating frequency is
decreased by about 4 to 15 Hz. Then, this operation is repeated every
60 seconds until the temperature of the indoor unit heat exchanger
drops below the overheat protection temperature.
Once the temperature of the indoor unit heat exchanger drops below
the overheat protection temperature, the operating frequency is
increased by about 4 to 10 Hz every 60 seconds until the normal oper-
ation condition resumes.
If the temperature of the indoor unit heat exchanger exceeds the over-
heat protection temperature for 60 seconds at minimum operating fre-
quency, the compressor stops operating and then restarts after about
180 seconds, and the abovementioned control is repeated.
1.8. Outdoor unit overheat prevention control
During cooling operation, if the temperature of the outdoor unit heat
exchanger exceeds the outdoor unit heat exchanger overheat preven-
tion temperature (about 55°C), the operating frequency is decreased
by about 4 to 15 Hz. Then, this operation is repeated every 60 sec-
onds until the temperature of the outdoor unit heat exchanger drops to
about 54°C or lower.
Once the temperature of the outdoor unit heat exchanger drops to
about 54°C or lower, the operating frequency is increased by about 4
to 10 Hz every 60 seconds until the normal operation condition
resumes.
If the temperature of the outdoor unit heat exchanger exceeds the out-
door unit heat exchanger overheat protection temperature for (120 sec
: outdoor temperature ≥40°C •60 sec : outdoor temperature < 40°C)
at minimum operating frequency, the compressor stops operating and
then restarts after about 180 seconds, and the abovementioned con-
trol is repeated.
1.9. Compressor overheat prevention control
If the temperature of the compressor exceeds the compressor over-
heat prevention temperature (110°C), the operation frequency is
decreased by about 4 to 10 Hz. Then, this operation is repeated every
60 seconds until the temperature of the compressor drops below the
overheat protection temperature (100°C).
Once the temperature of the compressor drops below the overheat
protection temperature, the operating frequency is increased by about
4 to 10 Hz every 60 seconds until the normal operation condition
resumes.
If the temperature of the compressor exceeds the overheat protection
temperature (for 120 seconds in cooling operation or 60 seconds in
heating operation) at minimum operating frequency, the compressor
stops operating and then restarts after about 180 seconds, and the
abovementioned control is repeated.
Compressor operation
ON operation on
remote control
OFF operation on
remote control
Compressor ON
Compressor ON Compressor can
turn ON
Compressor remains OFF
for 180 seconds
Indoor unit heat exchanger temperature
38
23
35
21
Set fan speed
Indoor unit fan at low speed
Indoor unit fan in non-operation

AEX12GRN
2 – 9
1.10. Startup control
When the air conditioner starts in the cooling or heating mode, if the
room temperature is 2°C higher than the set temperature (in cooling
operation) or 3.5°C lower (in heating operation), the air conditioner
operates with the operating frequency at maximum. Then, when the
set temperature is reached, the air conditioner operates at the operat-
ing frequency determined by fuzzy logic calculation, then enters the
normal control mode after a while.
1.11. Peak control
If the current flowing in the air conditioner exceeds the peak control
current (see the table below), the operation frequency is decreased
until the current value drops below the peak control current regardless
of the frequency control demand issued from the indoor unit based on
the room temperature.
1.12. Outdoor unit fan delay control
The compressor stops immediately after cooling, dehumidifying or
heating operation is shut down, but the outdoor unit fan continues
operation for 50 seconds before it stops.
1.13. Defrosting
1.13.1 Reverse defrosting
The defrost operation starts when the compressor operating time
exceeds 20 minutes during heating operation, as shown below, and
the outside air temperature and the outdoor unit heat exchanger tem-
perature meet certain conditions. When the defrost operation starts,
the indoor unit fan stops. The defrost operation stops when the out-
door unit heat exchanger temperature rises to about 13C or higher or
the defrosting time exceeds 10 minutes.
1.14. ON timer
The ON timer can be activated by pressing the ON timer button. When
the ON timer is activated, the operation start time is adjusted based on
fuzzy logic calculations 1 hour before the set time so that the room
temperature reaches the set temperature at the set time.
1.15. OFF timer
The OFF timer can be activated by pressing the OFF timer button.
When the OFF timer is set, the operation stops after the set time.
When this timer is set, the compressor operating frequency lowers for
quieter operation, and the room temperature is gradually varied after
one hour (reduced 1°C three times (max. 3°C) in heating, or increased
0.3°C three times (max. 1°C) in cooling or dehumidifying operation) so
that the room temperature remains suitable for comfortable sleeping.
1.16. Power ON start
If a jumper cable is inserted in the location marked with HAJP on the
indoor unit control printed circuit board (control PCB), connecting the
power cord to an AC outlet starts the air conditioner in either cooling or
heating mode, which is determined automatically by the room temper-
ature sensor.
When a circuit breaker is used to control the ON/OFF operation,
please insert a jumper as described above.
1.17. Self-diagnostic malfunction code display
1.17.1 Indoor unit
1) When a malfunction is confirmed, all relays turn off and a flashing
malfunction code number is displayed to indicate the type of mal-
function.
When the air conditioner is in non-operating condition, holding
down AUX button for more than 5 seconds activates the malfunc-
tion code display function.
The operation continues only in the case of a serial open-circuit,
and the main relay turns off after 30 seconds if the open-circuit con-
dition remains.
In the case of a serial short-circuit, the air conditioner continues
operating without a malfunction code display, and the main relay
turns off after 30 seconds if the short-circuit condition remains.
The malfunction information is stored in memory, and can be
recalled later and shown on display.
2) The self-diagnostic memory can be recalled and shown on the dis-
play by stopping the operation and holding down AUX button for
more than 5 seconds.
3) The content of self-diagnosis (malfunction mode) is indicated by a
flashing number.
(For details, refer to the troubleshooting section.)
1.17.2 Outdoor unit
If a malfunction occurs, LED1 on the outdoor unit flashes in 0.2-sec-
ond intervals as shown below.
1.18. Information about auto mode
In the AUTO mode, the temperature setting and mode are automati-
cally selected according to the room temperature and outdoor temper-
ature when the unit is turned on.
During operation, if the outdoor temperature changes, the temperature
settings will automatically slide as shown in the chart.
Model Peak control current
Cooling operation Heating operation
AY-XP12GR-N Approx. 6.6 A Approx.8.7 A
20 min or more 20 min or more 20 min or more
Defrosting
Max. 10 min
Defrosting
Max. 10 min
Start of
heating
operation
Heating operation
Set temperature
Activation of
OFF timer
1hour
later
Max.
1.5 hours
later
Max.
2 hours
later
Timer setting
reached
1hour
later
Max.
1.5 hours
later
Max.
2 hours
later
Timer setting
reached
Activation of
OFF timer
Set temperature
-1
O
C-1
O
C-1
O
C
0.3
O
C0.3
O
C0.3
O
C
Cooling/dehumidifying operation
1 sec 1 sec 0.6 sec
ON
OFF
(Example) Compressor high temperature abnormality
Modes and Temperature Settings
the figures in ( ) are temperature settings

AEX12GRN
2 – 10
1.19. Airflow control
The airflow control holds the two upper and lower louvers at special
positions during operation to prevent discharged air from directly blow-
ing onto people in the room.
1.19.1 Cooling/dehumidifying operation
When the airflow button is pressed the upper louver is set at an
upward angle to send the air along the ceiling.
1.19.2 Heating
When the airflow button is pressed the lower louver is set at a down-
ward angle to send the air directly toward the floor.
1.20. Difference of operation in Auto and Manual modes
In the Auto mode, the temperature setting is automatically determined
based on the outside air temperature. In addition, the air conditioner
operation differs from the operation in the Manual mode as explained
below.
1.20.1 Difference relating to set temperature
1.21. Dehumidifying operation control
If the room temperature is 26°C or higher when dehumidifying opera-
tion starts, the dehumidifying operation provides a low cooling effect in
accordance with the room temperature setting automatically deter-
mined based on the outside air operation. (The setting value is the
same as the set temperature for cooling operation in the auto mode.)
If the room temperature is lower than 26°C when dehumidifying opera-
tion starts, the dehumidifying operation minimizes the lowering of the
room temperature.
1.22. Self Clean operation
Heating or Fan operation and Cluster operation are performed simulta-
neously.
The judgment of whether Heating or Fan operation is used is based on
the outside air temperature at 3 minutes after the start of internal
cleaning.
The operation stops after 40 minutes. (The air conditioner shows the
remaining minutes: 40 →39 →38 ... 3 →2 →1)
1.23. Plasmacluster Ion function
Operating the Plasmacluster Ion button while the air conditioner is in
operation or in non-operation allows the switching of the operation
mode in the following sequence: “Air Clean operation” →“Stop”.
• “Self Clean operation” generates about equal amounts of (+)ions
and (-)ions from the cluster unit to provide clean air.
If the Plasmacluster Ion generation function is operated together with
the air conditioner operation, the indoor unit fan speed and louver
direction are in accordance with the air conditioner settings.
If the Plasmacluster Ion generation function is used without operating
the air conditioning function, the indoor unit fan operates at a very low
speed and the upper louver is angled upward and the lower louver
remains horizontal. (The airflow volume and direction can be changed
by using the remote control.)
1.24. Hot keep
When the room temperature rises above the set temperature by 0.6°C
or more, the ON/OFF operation of the compressor and indoor unit fan
is controlled in order to lower the room temperature.
(The values indicated below, such as "0.6°C" and "1.3°C," vary
depending on the outside air temperature.)
1.24.1 Hot keep zone 1
With the compressor frequency at the lowest, if the room temperature
is higher than the set temperature by 0.6°C but no more than 1.3°C,
the following processes will be activated.
1) The compressor stops temporarily, and restarts after 2 minutes.
2) If the room temperature remains in the hot keep zone, the com-
pressor is turned OFF and ON in 3-minute intervals.
3) The indoor unit fan turns OFF and ON with a delay of 30 seconds
from the compressor OFF/ON.
4) After the above operation in 3-minute intervals is repeated four
times, the interval extends to 6 minutes.
1.24.2 Hot keep zone 2
If the compressor ON/OFF in hot keep zone 1 fails to bring the room
temperature within 1.3°C above the set temperature, the following pro-
cesses will be activated.
1) The compressor repeats a cycle of 8-minute OFF and 6-minute
ON.
2) After the second time, the compressor remains completely OFF
and only the indoor unit fan repeats OFF-ON in set intervals.
3) While the compressor is completely OFF in 2), the louvers are set
horizontally to prevent cold air from blowing.
The zone transition and the end of hot keep operation (room tempera-
ture lower than the set temperature) are judged when the compressor
ON period ends.
* This function cannot be repealed.
1.25. Winter cool
Cooling operation is available during the winter season by the built in
winter cool function.
Lower limit of outdoor temperature range is -10°C DB.
When the outside air temperature is low, the outdoor unit fan operates
at slower speed.
NOTE: Built-in protect device may work when outdoor temperature
falls below 21°C DB., depending on conditions.
Temperature setting method
Auto mode
Cooling Automatic temperature setting based on
outside air temperature. Can be changed
within ±2°C using remote control.
Heating
Dehumidifying
Manual mode
Cooling Can be changed between 18 and 32°C
using remote control.
Heating Can be changed between 18 and 32°C
using remote control.
Dehumidifying Automatic setting. Can be changed
within ±2°C.
Heating operation Fan operation
24
O
C
Outside air temperature
1.3OC
0.6OC
Set temperature

AEX12GRN
2 – 11
1.26. Auto restart
When power failure occures, after power is recovered, the unit will
automatically restart in the same setting which were active before the
power failure.
1.26.1 Operating mode (Cool, Heat, Dry)
• Temperature adjustment (within 2°C range) automatic operation
• Temperature setting
• Fan setting
• Air flow direction
• Power ON/OFF
• Automatic operation mode setting
• Swing louvre
• Plasmacluster mode
1.26.2 Setting not memorized
• Timer setting
• Full power setting
• Internal cleaning
1.26.3 Disabling auto restart function
By removing (cutting) jumper J (JPJ) on the printed circuit board
(PCB), the auto restart function can be disabled.
2. Explanation of cluster circuit
The cluster unit generates cluster ions, which are circulated throughout the room by the air flow created by the blower fan (indoor unit fan motor) in
the air conditioner unit.
1) When microcomputer output turns "H," the IC6 output changes to "Lo," turning ON the SSR and applying 230 V to the cluster unit for the genera-
tion of cluster ions (positive and negative ions).
3. Outline of PAM circuit
3.1. PAM (Pulse Amplitude Modulation)
The PAM circuit varies the compressor drive voltage and controls the rotation speed of the compressor.
The IGBT shown in the block diagram charges the energy (electromotive force) generated by the reactor to the electrolytic capacitor for the inverter
by turning ON and OFF.
1
3
12V
SSR
C23
RE RH
R20
IC6
AC230V
Microcomputer output
1
5
3
6
Cluster unit
R23
R75 R76
PAM drive circuit block diagram
Reactor L5
[PAM drive circuit]
+
Microcomputer (IC1)
AC
230V
Compressor
Reactor L6
Noise
filter
AC clock
detection
circuit
DB1
IPM
DB2
Compressor
position
detector
IGBT
drive
circuit
IGBT
Overvoltage
detection
circuit

AEX12GRN
2 – 12
When the IGBT is ON, an electric current flows to the IGBT via the reactor (L5), (L6) and diode bridge (DB2).
When the IGBT turns OFF, the energy stored while the IGBT was ON is charged to the voltage doubler capacitor via the diode bridge (DB1).
As such, by varying the ON/OFF duty of the IGBT, the output voltage is varied.
3.2. High power factor control circuit
This circuit brings the operating current waveform closer to the waveform of commercial power supply voltage to maintain a high power factor.
Because of the capacitor input, when the PAM circuit is OFF, the phase of the current waveform deviates from the voltage waveform as shown below.
To prevent this deviation, a current is supplied during the periods indicated by "O" in the diagram.
To determine the length of period to supply a current, the zero-cross timing of the AC input voltage is input to the microcomputer via the clock circuit.
The power source frequency is also determined at the same time.
The IGBT turns ON after the time length determined by the zero-cross point to supply a current to the IGBT via the reactor.
This brings the current waveform closer to the voltage waveform in phase.
As described above, the ON/OFF operation of the IGBT controls the increase/decrease of the compressor power supply voltage (DC voltage) to
improve the compressor efficiency and maintain a high power factor by keeping the current phase closer to that of the supply voltage.
3.2.1 Detailed explanation of PAM drive circuit sequence
3.2.2 AC clock (zero-cross) judgment
• The clock circuit determines the time from one rising point of the clock waveform to the next rising point.
The detected clock waveform is used to judge the power source frequency (50Hz).
• The zero-cross of the AC voltage is judged as the rising of the clock waveform, as shown in the diagram above.
3.2.3 IGBT ON start time (delay time B)
• Based on the zero-cross of the AC voltage, the IGBT turns ON after a delay time set according to the power source frequency.
3.2.4 IGBT ON time (C)
• After the above delay time, the IGBT turns ON to supply a current to the reactor.
• The ON time of the IGBT determines the amount of energy (level of DC voltage rise) supplied to the reactor.
DC voltage level in each operation mode (varies depending on external load conditions)
– Cooling operation --- 220 to 240 V
– Heating operation --- 220 to 280 V
Stored energy
Reactor
L5
L6
DB1
DB2
IGBT
IGBT ON
IGBT OFF
AC voltage waveform
AC voltage and current waveform when PAM is ON
AC current waveform
IGBT ON period
Zero-cross detection
AC voltage waveform
AC current waveform
AC voltage and current waveforms when PAM is OFF
AC voltage waveform
Clock
IGBT ON
A
BC
A
B
C
50Hz
1.2mS
1.2mS
0.25 2.3mS

AEX12GRN
2 – 13
3.3. PAM protection circuit
To prevent excessive voltage of PAM output from
damaging the IPM and electrolytic capacitor as well
as the control printed circuit board (PCB), this circuit
monitors the PAM output voltage and turns off the
PAM control signal and PAM drive immediately
when an abnormal voltage output is generated. At
the same time, it shuts off the compressor operation.
The PAM output voltage is distributed to pin (4) of
the comparator (IC8). If this voltage exceeds the ref-
erence voltage at pin (5) of the IC8, the output of the
comparator (IC8) reverses (from H to L) and it is
input to pin (38) of the microcomputer (IC1) to halt
the PAM drive.
The protection voltage level is as follows.
3.3.1 Details of troubleshooting procedure for PAM
1) PAM shutdown due to error
1) When the DC voltage detection circuit sends a signal exceeding the specified voltage to the microcomputer
DC voltage of 350 V or higher (detection circuit input voltage of about 9.2 V or higher) [IC8 pin (4)]
– When an error is detected
• PAM IGBT turns OFF.
• Compressor turns OFF.
• All units shut down completely when the error occurs four times.
2) When the outdoor unit clock waveform differs from the specified value immediately before the PAM IGBT turns ON
When there is no clock waveform input
When a clock signal of other than specified power source frequency (50/60 Hz) is input
– When an error is detected
• PAM IGBT does not turn ON.
• Compressor operates normally.
• Complete shutdown does not occur.
2) PAM error indication
In case of error “1)”
– An error signal is sent to the indoor unit as soon as an error is generated.
• Malfunction No. 14-0 is indicated when the error code is called out by the indoor unit's self-diagnosis function.
– The LED on the outdoor unit flashes 14 times when an error is generated.
• The LED continues flashing in the 14-time cycle even after the compressor stops operating.
• The LED turns off (data is deleted from the memory) when the outdoor unit power is turned off.
In case of error “2)”
– An error signal is sent to the indoor unit as soon as an error is judged.
• Malfunction No. 14-1 is indicated when the error code is called out by the indoor unit's self-diagnosis function.
– The LED on the outdoor unit flashes 14 times when an error is judged.
• The LED on the outdoor unit flashes in normal pattern when the compressor stops operating.
(Compressor OFF or Thermostat OFF from remote control)
* When a user complains that the air conditioner does not provide sufficient cool air or warm air
In addition to conventional error-generating reasons, there is a possibility that the PAM IGBT does not turn ON even if the compressor is operating.
In that case, the DC voltage does not rise even though the compressor is operating, and lowers to the 180-VDC level.
– Check items
• Clock circuit check
• PAM IGBT check
• Fuse (Fu6) open-circuit check
R2
255K
C10C9
420V
750uF R5
300K
R7
23.7K
R8
23.7K
0V
0V 0V
IC8
15V
R113
19.1KF
R112
15K
5V
R114
1M R115
1.8K R116
1K
5
4
2
(Overvoltage detection)
During abnormal voltage output
IC1
38

AEX12GRN
2 – 14
4. Explanation of IPM drive circuit
The IPM for compressor drive is made by Mitsubishi Electric.
The power supply for the IPM drive, the shunt resistance for overcurrent detection, etc., are provided outside the IPM (control PCB).
4.1. IPM drive power supply circuit
The power supply for the upper-phase IGBT (HU, HV, HW) drive employs a bootstrap system, and provides power to the upper-phase IC.
The 15-V power supply for the lower-phase IC is provided by the control printed circuit board (PCB).
4.1.1 Brief explanation of bootstrap system (single power drive system)
To supply power to the upper-phase IC, the microcomputer (IC1) turns ON the lower-phase IGBT (LU, LV, LW).
This results in a charging current that flows to the electrolytic capacitor of each upper-phase IC input and charges the bootstrap capacitor with a 15-V
current.
The power supply for the subsequent stages is charged while the lower-phase IGBT is ON in ordinary compressor drive control.
P(Vcc)
U,V,W,
VD
VDB
VCIN(n)
N-side
IGBT
N(GN
D
Bootstrap capacitor
High-voltage-withstanding,
high-speed recovery diode
LVIC
(LU,LV,LW)
HVIC
(HU,HV,HW)
Bootstra
p
circuit
Initial charge period
Charging current group

AEX12GRN
2 – 15
4.1.2 DC overcurrent detection circuit
When a current of about 25 A or higher flows through the shunt resistance (R49) on the control printed circuit board (PCB), the voltage at this resis-
tance is input to IPM CIN pin (26). Then, the gate voltage of the lower-phase IGBT (LU, LV, LW) inside the IPM turns OFF to cut off the overcurrent. At
the same time, an L output of about 1.8 ms is generated from IPM Fo pin (24), and this results in an L input to overcurrent detection input pin (34) of
the microcomputer (IC1) and turns OFF the PWM signal output (IC1 pins (51) through (56)) to the IGBT gate.
SET
RESET
(About 22 A)
SC
SC reference voltage
Delay by CR time constant circuit
About 1.8 ms
a1
Protection circuit status
Output current Ic (A)
Sense voltage relative
to shunt resistance
Error output Fo
(Lower phase)
Internal IGBT gate
IPM overcurrent
detection circuit
5V
0V
IC1
R49 Overcurrent
Shunt resistance
P
N
CiN
FO
24
26
34

AEX12GRN
2 – 16
5. 120°energizing control (digital position detection control)
This control system detects the digital position detection signal and adjusts the rate of acceleration/deceleration accordingly.
The motor's induced voltage waveform is input to the comparator in the form of PWM-switched pulse waveform, and a position detection signal is
generated as a reference voltage equaling 1/2 of 280 VDC. However, since there is no induced voltage waveform when the PWM waveform is OFF,
the microcomputer performs internal processing so that detection is enabled only when it is ON. Based on the detected position signal, actual PWM
waveform output timing is determined. Since it does not use a filter circuit, the detection accuracy is high.
The microcomputer performs internal processing to cancel spike voltage during the regenerative process.
Furthermore, even if the induced voltage is low, position detection is still possible, thus allowing sensor-less operation at low rotation speed in the ini-
tial stage of operation. This reduces the starting current and improves the IPM reliability.
Comparator output waveform
(Position signal waveform)
Terminal voltage waveform
Reference voltage
(1/2 of DC voltage)
Spike voltage
(cancelled)