Carrier 40MBDAQ User manual

Specifications subject to change without notice.
TABLE OF CONTENTS
PAGE
SAFETY CONSIDERATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
INDOOR UNIT SIZES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
MODEL NUMBER NOMENCLATURE . . . . . . . . . . . . . . . . . . . . . 2
ELECTRICAL DATA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
WIRING. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
CONNECTION DIAGRAMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
WIRING DIAGRAMS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
REFRIGERANT CYCLE DIAGRAMS . . . . . . . . . . . . . . . . . . . . . . 6
SYSTEM EVACUATION AND CHARGING. . . . . . . . . . . . . . . . . 8
TROUBLESHOOTING. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
DIAGNOSIS AND SOLUTION . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
DISASSEMBLY INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . 48
APPENDICES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
SAFETY CONSIDERATIONS
Installing, starting up, and servicing air-conditioning equipment can
be hazardous due to unit pressures, electrical components, and
equipment location (roofs, elevated structures, etc.).
Only trained, qualified installers and service mechanics should install,
start-up, and service this equipment.
Untrained personnel can perform basic maintenance functions such as
coil cleaning. All other operations should be performed by trained
service personnel only.
When working on the equipment, observe the precautions in the
literature and on tags, stickers, and labels attached to the equipment.
Follow all safety codes. Wear safety glasses and work gloves. Keep a
quenching cloth and fire extinguisher nearby when brazing. Use care
in handling, rigging, and setting bulky equipment.
Read this manual thoroughly and follow all the warnings or cautions
included in the literature and attached to the unit. Consult local
building codes and the National Electrical Code (NEC) for special
requirements.
Recognize safety information. This is the safety-alert symbol .
When you see this symbol on the unit and in instructions or manuals,
be alert to the potential for personal injury. Understand these signal
words: DANGER, WARNING, and CAUTION.
These words are used with the safety-alert symbol. DANGER
identifies the most serious of hazards which will result in severe
personal injury or death. WARNING signifies hazards which could
result in personal injury or death. CAUTION is used to identify
unsafe practices which may result in minor personal injury or product
and property damage. NOTE is used to highlight suggestions which
will result in enhanced installation, reliability, or operation.
INTRODUCTION
This service manual provides the necessary information to service,
repair, and maintain the indoor units. This manual has an appendix (see
“APPENDICES” on page 55 for data needed to perform troubleshooting
tasks). Use the “TABLE OF CONTENTS” on page 1, to locate a desired
topic.
!
!
ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal injury or
death. Before installing, modifying, or servicing the unit, the main
electrical disconnect switch must be in the OFF position. There may
be more than 1 disconnect switch. Lock out and tag the switch with a
suitable warning label.
WA R N I N G
WA R N I N G
EXPLOSION HAZARD
Failure to follow this warning could
result in death, serious personal injury,
and/or property damage.
Never use air or gases containing oxygen
for leak testing or operating refrigerant
compressors. Pressurized mixtures of air
or gases containing oxygen can lead to
an explosion.
WAR NI NG
EQUIPMENT DAMAGE HAZARD
Failure to follow this caution may result in equipment damage or
improper operation. DO NOT bury more than 36 in. (914 mm) of
refrigerant pipe in the ground. If any section of pipe is buried, there
must be a 6 in. (152 mm) vertical rise to the valve connections on the
outdoor units. If more than the recommended length is buried,
refrigerant may migrate to the cooler buried section during the
extended periods of unit shutdown. This causes refrigerant slugging
and could possibly damage the compressor at start-up.
CAUTION
Service Manual
40MBDAQ
Ducted Style Ductless System
Size 09K to 58K

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2
INDOOR UNIT SIZES
Table 1 — Indoor Unit Size
MODEL NUMBER NOMENCLATURE
KBTUH V-PH-HZ MODEL NO.
9
208/230-60
40MBDAQ09XH3
12 40MBDAQ12XH3
18 40MBDAQ18XH3
24 40MBDAQ24XH3
36 40MBDAQ36XH3
48 40MBDAQ48XH3
58 40MBDAQ58XH3
INDOOR UNIT
40
M BD A 09 X H
40 = FAN COIL UNIT
M = ALL
VARIATIONS
A = STANDARD
H = HIGH STATIC
INDOOR FAN COIL UNIT TYPE
D = DUCTED
NOMINAL CAPACITY
09 - 3/4 TON
12 - 1 TON
24 - 2 TONS
36 - 3 TONS
48 - 4 TONS
58 - 5 TONS
MODEL = B
MAJOR SERIES
UNIT TYPE
C= COOLING
Q= HEAT PUMP
Q
MAXIMUM NUMBER OF
FAN COIL UNITS CONNECTED
TO THE OUTDOOR UNIT
A = 1:1 F= 1:6
B = 1:2 G= 1:7
C= 1:3 H = 1:8
D= 1:4 J = 1:9
E= 1:5 X = INDOOR UNIT
3
ELECTRICAL CHARACTERISTICS
3 = 208-230/1/60
23 10001
Week of Manufacture
Sequential Serial Number
V
V = ALL MODELS
Year of Manufacture
16
Use of the AHRI Certified
TM Mark indicates a
manufacturer’s
participation in the
program For verification
of certification for individual
products, go to
www.ahridirectory.org.

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3
ELECTRICAL DATA
Table 2 — Electrical Data
LEGEND
FLA - Full Load Amps
WIRING
All wires must be sized per NEC (National Electrical Code) or CEC
(Canadian Electrical Code) and local codes. Use Electrical Data table
MCA (minimum circuit amps) and MOCP (maximum over current
protection) to correctly size the wires and the disconnect fuse or breakers
respectively.
SIZES 09-24 RECOMMENDED CONNECTION METHOD
FOR POWER AND COMMUNICATION WIRING
Power and Communication Wiring: The main power is supplied to the
outdoor unit. The field supplied 14/3 power/communication wiring, from
the outdoor unit to the indoor unit, consists of four (4) wires and provides
the power for the indoor unit. Two wires are high voltage AC power, one
is communication wiring and the other is a ground wire.
To minimize communication interference: If installed in a high
Electromagnetic field (EMF) area and communication issues arise, a 14/2
stranded shielded wire can be used to replace L2 and (S) between the
outdoor and indoor units - landing the shield onto the ground in the
outdoor unit only.
WIRING SIZES 09-24
SIZES 36-58 RECOMMENDED CONNECTION METHOD
FOR POWER AND COMMUNICATION WIRING
Power and Communication Wiring: The main power is supplied to the
outdoor unit. The field supplied power wiring from the outdoor unit to the
indoor unit consists of three (3) wires and provides the power for the
indoor unit. Two wires are high voltage AC power and one is a ground
wire. To minimize voltage drop, the factory recommended wire size is 14/
2 stranded with a ground.
Communication Wiring: A separate shielded stranded copper conductor
only, with a 600 volt rating and double insulated copper wire, must be
used as the communication wire from the outdoor unit to the indoor unit.
Please use a separate shielded 16GA stranded control wire.
WIRING SIZES 36-58
INDOOR UNITS V-PH-HZ
INDOOR FAN
MAX FUSE CB AMP
FLA HP W_Out SYSTEM POWER
FACTOR (%)
9K
208-230/1/60
0.8 1/5 160 62.4
Refer to the outdoor unit installation instructions.
Indoor unit is powered by the outdoor unit.
12K 1.1 1/5 160 97.2
18K 1.8 1/5 160 71
24K 2.2 1/5 160 89.6
36K 2.2 3/4 560 98.6
48K 2.9 3/4 560 99.1
58K 2.5 15/16 700 99.3
CABLE CABLE SIZE REMARKS
Connection
Cable 14AWG 3 wire + Ground 1Φ208/230 V (Stranded wire is recommended)
CABLE CABLE SIZE REMARKS
Power
Connection Cable 14AWG 2 wire + Ground 1Φ208/230V
Communication
Cable
16AWG 2 wire stranded shielded
control wire
EQUIPMENT DAMAGE HAZARD
Failure to follow this caution may result in equipment damage or improper
operation. Wires should be sized based on NEC and local codes.
CAUTION
EQUIPMENT DAMAGE HAZARD
Failure to follow this caution may result in equipment damage or
improper operation.
CAUTION
EQUIPMENT DAMAGE HAZARD
Failure to follow this caution may result in equipment damage or
improper operation.
Be sure to comply with local codes while running wire from the
indoor unit to the outdoor unit.
Every wire must be connected firmly. Loose wiring may cause the
terminal to overheat or result in unit malfunction. A fire hazard may
also exist. Ensure all wiring is tightly connected.
No wire should touch the refrigerant tubing, compressor or any
moving parts.
Disconnecting means must be provided and shall be located within
sight and readily accessible from the air conditioner.
CAUTION

40MBDAQ: Service Manual
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4
CONNECTION DIAGRAMS
Fig. 1 — Connection Diagram - Sizes 9K,12K, 18K, 24K
Fig. 2 — Connection Diagram - Size 36K
Fig. 3 — Connection Diagram - Sizes 48K to 58K

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5
WIRING DIAGRAMS
Fig. 4 — Wiring Diagram - Sizes 9K, 12K, 18K, 24K
Fig. 5 — Wiring Diagram - Sizes 36K, 48K, 58K

40MBDAQ: Service Manual
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6
REFRIGERANT CYCLE DIAGRAMS
Fig. 6 — Refrigerant Cycle Diagram - Sizes 9K, 12K
Fig. 7 — Refrigerant Cycle Diagram - Size 18K

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7
REFRIGERANT DIAGRAMS (CONT)
Fig. 8 — Refrigerant Cycle Diagram - Size 24K
Fig. 9 — Refrigerant Cycle Diagram - Sizes 36K, 48K, 58K
Refrigerant Lines
General refrigerant line sizing:
1. The outdoor units are shipped with a full charge of R410A refrigerant. All charges, line sizing, and capacities are based on runs of 25 ft. (7.6 m). For
runs over 25 ft. (7.6 m), consult the unit’s product data.
2. Minimum refrigerant line length between the indoor and outdoor units is 10 ft. (3 m).
3. Refrigerant lines should not be buried in the ground. If it is necessary to bury the lines, not more than 36 in. (914 mm) should be buried. Provide
a minimum 6 in. (152 mm) vertical rise to the service valves to prevent refrigerant migration.
4. Both lines must be insulated. Use a minimum of 1/2 in. (12.7 mm) thick insulation. Closed-cell insulation is recommended in all long-line
applications.
5. Special consideration should be given to isolating the interconnecting tubing from the building structure. Isolate the tubing so vibration or noise is
not transmitted into the structure.
6. For piping runs greater than 25 ft. (7.6 m), add refrigerant up to the allowable length as specified in the product data.

40MBDAQ: Service Manual
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8
SYSTEM EVACUATION AND CHARGING
Refrigerant tubes and indoor coil should be evacuated using the
recommended deep vacuum method of 500 microns. The alternate triple
evacuation method may be used if the following procedure is followed.
Always break a vacuum with dry nitrogen.
System Vacuum and Charge
Using Vacuum Pump
1. Completely tighten the flare nuts (A, B, C, D, E). Fully open all
circuits service valves. Connect the manifold gage charge hose to the
charge port of the low side Master service valve to evacuate all
circuits at the same time (see Fig. 10).
2. Connect the charge hose to the vacuum pump.
3. Fully open the low side of the manifold gage (see Fig. 11).
4. Start the vacuum pump.
5. Evacuate using the triple evacuation method.
6. After the evacuation is complete, fully close the low side of the
manifold gage and stop the vacuum pump operation. The factory
charge contained in the outdoor unit is good for up to 25 ft. (8 m) of
line length.
7. Disconnect the charge hose from the charge connection of the low
side service valve.
8. Fully open the service valves (B and A).
9. Securely tighten the service valve caps.
A220978
Fig. 10 — Service Valve
A220979
Fig. 11 — Manifold
Deep Vacuum Method
The deep vacuum method requires a vacuum pump capable of pulling a
vacuum of 500 microns and a vacuum gage capable of accurately measuring
this vacuum depth. The deep vacuum method is the most positive way of
ensuring a system is free of air and liquid water (see Fig. 12).
A220980
Fig. 12 — Deep Vacuum Method
Triple Evacuation Method
The triple evacuation method should be used. Refer to Fig. 13 and
proceed as follows:
1. Pump the system down to 1500 microns and allow the pump to
continue operating for an additional 15 minutes.
2. Close the service valves and shut off the vacuum pump.
3. Connect a dry nitrogen cylinder and regulator to the system and
break the vacuum until the system reaches 2 psig.
4. Close the service valve and allow the system to stand for one hour.
During this time, the dry nitrogen can diffuse throughout the system
absorbing moisture.
5. Pump the system down to 1000 microns.
6. Break the vacuum with dry nitrogen (2 psig).
7. Pump the system down to 500 microns.
8. Perform the hold test for 30 minutes.
A220981
Fig. 13 — Triple Evacuation Method
Final Tubing Check
IMPORTANT: Check to ensure the factory tubing on both the
indoor and outdoor unit has not shifted during the shipment.
Ensure the tubes are not rubbing against each other or any
sheet metal. Pay close attention to feeder tubes, ensuring the
wire ties on the feeder tubes are secure and tight.
UNIT DAMAGE HAZARD
Failure to follow this caution may result in equipment damage or
improper operation.
Never use the system compressor as a vacuum pump.
CAUTION
Outdoor Unit Indoor Uni
t
Refrigerant
Service Valve
Low Side
High Side
A
B
C
D
Manifold Gage
500 microns
Low side valve High side valve
Charge hose Charge hose
Vacuum pump
Low side valve
500
MINUTES
01234567
1000
1500
LEAK IN
SYSTEM
VACUUM TIGHT
TOO WET
TIGHT
DRY SYSTEM
2000
MICRONS
2500
3000
3500
4000
4500
5000
CHECK FOR TIGHT, DRY SYSTEM
(IF IT HOLDS DEEP VACUUM)
EVACUATE TO 1500 MICRONS
EVACUATE TO 500 MICRONS MINIMUM (HOLD FOR 30 MINUTES)
RELEASE CHARGE INTO SYSTEM BY OPENING VALVES COMPLETELY
BREAK VACUUM WITH DRY NITROGEN TO 2 PSIG
EVACUATE TO 1000 MICRONS
BREAK VACUUM WITH DRY NITROGEN TO 2 PSIG

40MBDAQ: Service Manual
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9
Main Protection
Fan Speed is Out of Control
When the indoor fan speed remains too low (lower than 300RPM) for 50
seconds, the indoor fan shuts off and restarts 30 seconds later. If the
protection occurs three times when the fan motor restarts continuously,
the unit stops and the LED displays the failure.
When the outdoor fan speed remains too low (lower than 100 RPM) or
too high (higher than 1500 RPM) for 60 seconds, the unit stops and the
LED displays the failure then the malfunction clears 30 seconds later.
Evaporator low temperature T2 protection
•T2<32°F (0°C), the compressor stops and restarts when T2 ³41°F
(5°C)
•32°F (0°C) ≤T2 < 39.2°F (4°C), the compressor frequency is limited
and decreased to the lower level
•39.2°F (4°C) ≤T2 ≤44.6°F (7°C), the compressor maintains the
current frequency
•T2>44.6
°F (7°C), the compressor frequency is not limited
Operation Modes and Functions
FAN Mode
1. Outdoor fan and compressor stop
2. Temperature setting function is disabled, and no setting temperature
appears
3. Indoor fan can be set to high/med/low/auto
4. The louver operates the same in the COOLING mode
5. AUTO fan
A220982
Fig. 14 —Auto Fan
COOLING Mode
Indoor Fan Running Rules
In the COOLING mode, the indoor fan runs constantly and either speed
( high , medium , low or auto ) can be selected. When the setting temperature
is reached, if the compressor stops running, the indoor fan motor runs at the
minimum or setting speed. The indoor fan is controlled by the rules shown in
Fig. 15.
A220983
Fig. 15 — Indoor Fan Running Rules
..........................................................................
a
12°F (6°C)
T
1-75.2°F (24°C)
........................
10°F (5°C)
b........................
........................
c
8°F (4°C)
5°F (2.5°C)
d
2°F (1°C)
e
H
(H-L)*0.75+L
(H-L)*0.5+L
(H-L)*0.25+L
L
Setting Fan
Speed Actual Fan Speed
L
H
T1-Td °F (°C)
M
5
8
°F
(4.5
°
C)
°F
(3.0
°
C)
3
°F
(1.5
°
C)
5
8
°F
(4.5
°
C)
°F
(3.0
°
C)
3
°F
(1.5
°
C)
5
8
°F
(4.5
°
C)
°F
(3.0
°
C)
3
°F
(1.5
°
C)

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10
The AUTO fan is controlled by the rules shown in Fig. 16.
A220984
Fig. 16 — Indoor Fan Running Rules
Evaporator Temperature Protection
When the evaporator temperature is lower than the setting value, the
compressor stops.
HEATING Mode
Indoor Fan Running Rules
When the compressor is on, the indoor fan can be set to high/med/low/
auto/mute. When the indoor unit coil temperature is low, the anti-cold air
function starts and the indoor fan motor runs at a low speed and the speed
cannot be changed. When the temperature is lower than the setting value,
the indoor fan motor stops.
When the indoor temp reaches the setting temperature, the compressor
stops and the indoor fan motor runs at the minimum or setting speed (the
anti-cold air function is valid). The indoor fan is controlled by the rules
shown in Fig. 17.
A220985
Fig. 17 — Indoor Fan Running Rules
Auto Fan Action in HEATING Mode
A220986
Fig. 18 — Auto Fan Action in HEATING Mode
DEFROST Mode
If any one of the following items is satisfied, the unit enters the
DEFROST mode. After the compressor starts and runs, mark the
minimum value of T3 from the 10th minute to the 15th minute as T30.
1. If the compressor runs for 29 minutes and T3 < TCDI1, T3 ＋
T30SUBT3ONE ≦ T30.
2. If the compressor runs for 35 minutes and T3 < TCDI2, T3 ＋
T30SUBT3TWO ≦ T30.
3. If the compressor runs for 29 minutes. and T3 < TCDI3 for three
minutes.
4. If the compressor runs for 120 minutes and T3 < 5°F (−15°C).
Defrost End
If any one of the following items is satisfied, the DEFROST mode ends
and the machine reverts to the normal HEATING mode.
• T3 increases to a point higher than TCDE1.
• T3 maintains a point higher than TCDE2 for 80 seconds.
•Unit runs for 10 minutes in DEFROST mode.
A220987
Fig. 19 — Defrost Action
..........................................................................
a
12°F (6°C)
T
1-75.2°F (24°C)
........................
10°F (5°C)
b
........................
........................
c
8°F (4°C)
5°F (2.5°C)
d
2°F (1°C)
e
H
(H-L)*0.75+L
(H-L)*0.5+L
(H-L)*0.25+L
L
Setting Fan
Speed Actual Fan Speed
H=H
H+(H+=H+G)
M(M=M)
L(L=L)
L+(L+=L+D)
H- H-=H-G)
M+(M+=M+Z)
L-(L-=L-D)
M-(M-=M-Z)
L
H
T1-Td + 1.5 °C (3°F)
M
-3°F(-1.5°C)
-5°F(-3.0°C)
-8°F(-4.5°C)
-3°F(-1.5°C)
-5°F(-3.0°C)
-8°F(-4.5°C)
-3°F(-1.5°C)
-5°F(-3.0°C)
-8°F(-4.5°C)
............
............
T1-Td+3°F(1.5°C)
............
............
...............................
L
(H+-L)*0.2+L
(H+-L)*0.4+L
(H+-L)*0.6+L
(H+-L)*0.8+L
H+
...............................
0°F(0°C)
-2°F(-1°C)
-4°F(-2°C)
-6°F(-3°C)
-7°F(-4°C)
-9F(-5°C)
-11°F(-6°C)
-12°F(-6.5°C)
Compressor
Outdoor fan
4-Way valve
X1 10S
10S
no longer than 10min
X2

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11
Evaporator Coil Temperature Protection
A220988
Fig. 20 — Evaporator Coil Temperature Protection
NOTE:
• Off −Compressor stops
•Decrease−Decrease running frequency to lower level
•Hold−Maintain the current frequency
• Resume −No frequency limit
When the evaporator temperature is higher than the setting protection
value, the compressor stops.
Auto-Mode
This mode can be chosen with the remote control and the setting
temperature can be changed between 62°F (17°C)~86°F (30°C).
In the AUTO mode, the unit chooses the COOLING, HEATING or
FAN-ONLY mode according to DT (DT =T1.Ts).
Table 3 — Auto Mode
The indoor fan runs under AUTO fan in the relevant mode. The louver
operates the same as in the relevant mode. If the unit switches between the
HEATING and COOLING modes, the compressor stops for 15 minutes
and then chooses the mode according to T1−Ts. If the setting temperature is
modified, the unit chooses the running function again.
DRYING Mode
Indoor Fan Speed is Fixed
The indoor fan speed is fixed at BREEZE and cannot be changed. The
louver angle is the same as in the COOLING mode.
Low Indoor Room Temperature Protection
In the DRYING mode, if the room temperature is lower than 50 ° F (10 ° C),
the compressor stops and will not resume until the room temperature
exceeds 53.6 ° F (12 ° C).
Timer Function
Timing range is 24 hours
•TIMERON:The unit turns on automatically when reaching the
setting time.
•TIMER OFF: The unit turns off automatically when reaching the
setting time.
•TIMER ON/OFF: The unit turns on automatically when reaching the
setting “on” time, and then turns off automatically when reaching the
setting “off” time.
•TIMER OFF/ON: The unit turns off automatically when reaching the
setting “off” time, and then turns on automatically when reaching the
setting “on” time.
The timer function will not change the unit’s current operation mode.
Suppose the unit is off now; it will not start up first after setting the
TIMER OFF function. When the setting time is reached, the timer LED
turns off and the unit’s running mode is the same. The setting time is
relative time. The unit exits the timer function if it experiences a
malfunction.
Sleep Function
The SLEEP function is available in the COOLING, HEATING or
AUTO mode.
The operation process in the SLEEP mode is as follows:
• When cooling, the setpoint rises 2°F (1°C) (to a maximum of 86°F
(30°C) every one hour. Two (2) hours later, the room temperature stops
rising and the indoor fan remains at a low speed.
• When heating, setpoint decreases 2°F (1°C) (to a minimum of 62°F
(17°C) every one hour. Two (2) hours later, the setpoint stops
decreasing and the indoor fan is set at the low speed.
(Anti−Cold wind function has the priority).
Operation time in the SLEEP mode is seven (7) hours. After seven (7)
hours, the unit exits the SLEEP mode and powers off.
FORCED OPERATION Function
When the unit is off, press TOUCH to engage the FORCED AUTO
mode. Press TOUCH again within five seconds to engage the FORCED
COOLING mode. In the FORCED AUTO, FORCED COOLING or
any other operation mode, press TOUCH to turn off the unit.
FORCED OPERATION Mode
In the FORCED OPERATION mode, all the general protections and
remote control are available.
Operation Rules
FORCED COOLING Mode
The compressor runs at the F2 frequency and the indoor fan runs in the
BREEZE mode. After running for 30 minutes. the machine enters the
AUTO mode at the 75.2°F (24°C) setting temperature.
FORCED AUTO Mode:
The FORCED AUTO mode is the same as the normal AUTO mode with
a 75.2°F (24°C) setting temperature.
ΔT=T1-Ts Running Mode
ΔT＞4°F (2°C) Cooling
- 4 (-2°C) ≤ΔT≤2°C(4°F) Fan-Only
ΔT<-2°C (4°F) Heating
T
Estop
T2
T
Edown
Decrease
Hold
TEH2
Resume

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12
AUTO−RESTART Function
The indoor unit is equipped with an AUTO−RESTART function, which
is carried out through an auto−restart module. In the event of a sudden
power failure, the module memorizes the setting conditions prior to the
power failure. The unit resumes the previous operation setting (not
including the SWING function) automatically three (3) minutes after the
power returns.
If the memorization condition is the FORCED COOLING mode, the
unit runs in the COOLING mode for 30 minutes and switches to the
AUTO mode at the 75°F (24°C) setpoint. If the unit is off before the
power turns off and the unit is required to start up, the compressor delays
the start up for 1 minute before powering on. In other instances, the
compressor waits three (3) minutes before restarting.
FOLLOW ME
If the indoor PCB receives the signal, which results from pressing
FOLLOW ME on the remote controller or wired remote controller, the
buzzer emits a sound which indicates the FOLLOW ME function is
initiated. However, when the indoor PCB receives the signal from the
remote controller every three minutes, the buzzer will not respond. When
the unit is running with the FOLLOW ME function, the PCB controls
the unit according to the temperature from the FOLLOW ME signal, and
the temperature collection function of the room temperature sensor is
shielded.
When the FOLLOW ME function is available, the PCB controls the unit
according to the room temperature from the remote controller and the
setting temperature. The PCB changes the mode based on information
from the remote controller signal, however it is not affected by the setting
temperature.
If the unit is running under the FOLLOW ME function and the PCB
does not receive a signal from the remote controller for seven minutes or
after pressing FOLLOW ME again, the FOLLOW ME function turns
off automatically, and the temperature controls the unit according to the
room temperature detected from its own room temperature sensor and
setting temperature.
Refrigerant Leak Detection
With this new technology, the display area displays “EC” when the
outdoor unit detects a refrigerant leak. This function is only active in the
COOLING mode. This function helps to prevent the compressor from
being damaged by a refrigerant leak or a compressor overload.
• Open Condition: When the compressor is running, the T2 coil
temperature sensor value has no to very little change.
46°F (8°C) Heating
When the compressor is running, the indoor fan motor runs without the
ANTI-COLD air function. When the compressor is off, the indoor fan
motor is off.
Silence Operation
Press SILENCE on the remote control to initiate the SILENCE function.
When the SILENCE function is activated, the compressor running
frequency remains lower than F2 and the indoor unit emits a faint breeze,
which reduces the noise to the lowest level and creates a quiet and
comfortable space for the user.
Drain Pump Control
HEAT
A call for heat start the outdoor unit and the indoor blower follow its anti-
cold blow configuration. The pump will NOT turn on if the level switch
remains closed (no condensate present). If the level switch opens (water
level rise or switch malfunction), the pump starts in approximately 4
seconds.
If the level switch closes within 3 minutes, the pump continues to run for
one minute and then the pump turns off. If the level switch remains open
for three minutes, the blower turns off, the EEV closes, and the pump
turns off.
EE Alarm
If the level switch closes after the EE alarm has been posted, the EEV
opens, the blower starts, and the pump remains off.
COOL
A call for cool starts the indoor blower. When the compressor starts, the
pump turns on and continues to run until the outdoor unit cycles off
(single zone) or indoor unit = thermal OFF (MZ). If the level switch
opens (water level rise or switch malfunction), the pump remains on. If
the level switch closes within 3 minutes, the pump continues to run and
no alarm is posted. If the level switch remains open for 3 minutes, the
blower turns off, the EEV closes, and the pump powers off.
EE Alarm
If the level switch closes after the EE alarm has been posted, the EEV
opens, the blower starts, and the pump runs when the compressor starts.
NOTE: The EE alarm condition in the HEAT or COOL mode only
directly impacts the compressor operation of a single zone
system.
The Multi-zone outdoor unit continues to run unless the ducted unit is the
only indoor unit operating. A ducted unit on a multi-zone system
immediately restarts if the EE alarm clears and the compressor is running
to serve other units.

40MBDAQ: Service Manual
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13
Point Check Function
Press LED DISPLAY or AIR DIRECTION to check the next or front item’s information. When the air conditioner enters the Information Enquiry
status, it displays the code name in two seconds (see Table 4).
Table 4 — Information Enquiry
When the unit enters the information enquiry status, the code value appears for 25 seconds (see Table 5 on page 14).
ENQUIRY INFORMATION DISPLAYING CODE MEANING
T1 T1 T1 temp.
T2 T2 T2 temp.
T3 T3 T3 temp.
T4 T4 T4 temp.
T2B Tb T2B temp.
T5 T5 T5 temp.
TH TH TH temp.
Targeted Frequency FT Targeted Frequency
Actual Frequency Fr Actual Frequency
Indoor fan speed IF Indoor fan speed
Outdoor fan speed OF Outdoor fan speed
EXV opening angle LA EXV opening angle
Compressor continuous running time CT Compressor continuous running time
Causes of compressor stop ST Causes of compressor stop
Reserve A0
Reserve A1
Reserve .b0
Reserve .b1
Reserve .b2
Reserve .b3
Reserve .b4
Reserve .b5
Reserve .b6
Reserve .dl
Reserve Ac
Reserve Uo
Reserve Td

40MBDAQ: Service Manual
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14
Table 5 — Point Check
ENQUIRY INFORMATION DISPLAY VALUE MEANING REMARK
T1,T2,T3,T4,
T2B,TP,TH,
Targeted
Frequency,
Actual
Frequency
-1F,-1E,-1d,-1c,-1b,-1A -25,-24,-23,-22,-21,-20 1. The displaying temperature is the actual
value.
2. The temperature is °C no matter what kind
of remote control is used.
3. T1,T2,T3,T4,T2B display range:-25~70, TP
display range:-20~130.
4. Frequency display range: 0~159HZ.
5. If the actual value exceeds the range, it
displays the maximum value or minimum
value.
-19—99 -19—99
A0,A1,…A9 100,101,…109
b0,b1,…b9 110,111,…119
c0,c1,…c9 120,121,…129
d0,d1,…d9 130,131,…139
E0,E1,…E9 140,141,…149
F0,F1,…F9 150,151,…159
Indoor fan speed
/Outdoor fan speed
0OFF
1,2,3,4 Low speed, Medium speed, High speed,
Turbo For some big capacity motors
14-FF
Actual fan speed = Display value turns to
decimal value and then multiply by 10. The
unit is RPM.
For some small capacity motors, the display
value is from 14-F (hexadecimal), the
corresponding fan speed range is from 200-
2550 RPM.
EXV opening angle 0-FF
Actual EXV opening value = Display value turns to
decimal value and then multiply by 2.
Compressor continuous
running time 0-FF 0-255 minutes
If the actual value exceeds the range, it
displays the maximum value or minimum
value.
Compressor stop causes 0-99 For a detailed meaning, please consult with
an engineer. Decimal display
Reserve 0-FF

40MBDAQ: Service Manual
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
15
TROUBLESHOOTING
This section provides the required flow charts to troubleshoot problems
that may arise.
NOTE: Information required in the diagnoses can be found either on
the wiring diagrams or in the appendix.
Required Tools:
The following tools are needed when diagnosing the units:
• Digital multimeter
• Screw drivers (Phillips and straight head)
•Needle−nose pliers
• Refrigeration gauges
Recommended Steps
1. Refer to the diagnostic table, see Table 6 on page 16, and determine
the problem at hand.
2. Go to the chart, see “DIAGNOSIS AND SOLUTION” on page 17,
and follow the steps in the chart for the selected problem.
For ease of service, systems are equipped with diagnostic code display
LED’s on both the indoor and outdoor units. The outdoor diagnostic
display is on the outdoor unit board and is limited to very few errors.
The indoor diagnostic display is a combination of flashing LED’s on the
display panel on the front of the unit. If possible always check the
diagnostic codes displayed on the indoor unit first. The diagnostic codes
for the indoor and outdoor units are listed in the appendix (see
“APPENDICES” on page 55.
Problems may occur that are not covered by a diagnostic code, however
are covered by the diagnostic flow charts. These problems are typical air
conditioning mechanical or electrical issues that can be corrected using
standard air conditioning repair techniques.
For problems requiring measurements at the control boards, note the
following:
1. Always disconnect the main power.
2. When possible, check the outdoor board first.
3. Start by removing the outdoor unit top cover.
4. Reconnect the main power.
5. Probe the outdoor board inputs and outputs with a digital multi-
meter referring to the wiring diagrams.
6. Connect the red probe to the hot signal and the black probe to the
ground or negative.
7. Note that some of the DC voltage signals are pulsating voltages for
signal. This pulse should be rapidly moving at all times when there
is a signal present.
8. If it is necessary to check the indoor unit board, disconnect the main
power first.
9. Next, remove the unit’s front cover and then the control box cover.
10. Carefully remove the indoor board from the control box, place it
face up on a plastic surface (not metal).
11. Reconnect the main power and repeat steps 5, 6, and 7.
12. Disconnect the main power before reinstalling the board to avoid a
shock hazard and board damage.
Safety
Electricity remains in the capacitors even when the power supply is shut off. Do not forget to discharge the electricity in the capacitor.
A220989
Fig. 21 — Capacitors
For other models, connect discharge resistance (approx.100Ù 40W) or soldering iron (plug) between +, - terminals of the electrolytic capacitor on the
contrary side of the outdoor PCB.
A220990
Fig. 22 — Discharging Position
NOTE: Figure 22 is for reference only.
Electrolytic Capacitors
(HIGH VOLTAGE! CAUTION!)

40MBDAQ: Service Manual
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16
Indoor Unit Diagnostic Guides
Table 6 — Indoor Unit Error Display
For other errors:
The display board may show a garbled code or a code not listed in the service manual. Ensure this code is not a temperature reading.
Troubleshooting:
Test the unit using the remote control. If the unit does not respond to the remote, the indoor PCB needs to be replaced. If the unit responds, the display
board needs to be replaced.
Table 7 — Error Display on Two Way Communication Wired Controller
OPERATION LAMP TIMER LAMP DISPLAY ERROR INFORMATION SOLUTION
1 time OFF E0 Indoor unit EEPROM parameter error Page 17
2 times OFF E1 Indoor / outdoor unit communication error Page 18
4 times OFF E3 The indoor fan speed is operating outside of the normal range Page 21
5 times OFF E4 Indoor room temperature sensor T1 is in open circuit or has short circuited Page 25
6 times OFF E5 Evaporator coil temperature sensor T2 is in open circuit or has short circuited Page 21
7 times OFF EC Refrigerant Leakage Detection Page 26
8 times OFF EE Water-level alarm malfunction Page 27
9 times OFF E8 Communication error between master and slave unit (for twins system) Page 29
10 times OFF E9 Another indoor unit malfunction (for twins system) --
11 times OFF Ed Outdoor unit malfunction Page 28
1 time ON F0 Current overload protection Page 30
2 times ON F1 Outdoor room temperature sensor T4 is in open circuit or has short circuited Page 25
3 times ON F2 Condenser coil temperature sensor T3 is in open circuit or has short circuited Page 25
4 times ON F3 Compressor discharge temperature sensor TP is in a open circuit or has short-
circuited Page 25
5 times ON F4 Outdoor unit EEPROM parameter error Page 17
6 times ON F5 The outdoor fan speed is operating outside of the normal range Page 21
7 times ON F6 Evaporator coil outlet temperature sensor T2B is in open circuit or has short circuited
(for free-match indoor units) Page 25
11 times ON FA Communication error between indoor two chips Page 17
1 time FLASH P0 IPM malfunction or IGBT over-strong current protection Page 32
2 times FLASH P1 Over voltage or over low voltage protection Page 33
3 times FLASH P2 Top temperature protection of compressor Page 34
5 times FLASH P4 Inverter compressor drive error Page 32
6 times FLASH P5/-- Indoor units mode conflict (match with multi outdoor unit) Page 43
7 times FLASH P6 High pressure protection or low pressure protection Page 35
8 times FLASH P7 IGBT temperature sensor TH is in open circuit or has short circuited Page 25
DISPLAY ERROR INFORMATION SOLUTION
F0 Communication error between wired controller and indoor unit Page 30
EHb3 Communication error between wire controller and indoor unit (for KSACN0701AAA series wired controller) Page
E1 Indoor / outdoor unit communication error Page 18
E2 Indoor room temperature sensor T1 is in open circuit or has short circuited --
E3 Evaporator coil temperature sensor T2 is in open circuit or has short circuited Page 21
E4 Indoor coil outlet temperature sensor T2B is in open circuit or has short circuited Page 25
E5 Outdoor coil temperature sensor malfunction T3 or Outdoor ambient temperature sensor malfunction T4 or Compressor
discharge temperature sensor TP is in open circuit or has short circuited Page 21
E7 Indoor EEPROM malfunction Page
E8 The indoor fan speed is operating outside of the normal range Page 29
EA Current overload protection Page
EIPM malfunction or IGBT over-strong current protection Page
EOutdoor unit malfunction Page
EE Water-level alarm malfunction Page 27
EF Other malfunction --

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17
DIAGNOSIS AND SOLUTION
E0 / F4 (EEPROM parameter error Diagnosis and Solution)
Description: Indoor or outdoor PCB main chip does not receive feedback from EEPROM chip.
Recommended parts to prepare:
• Indoor PCB
• Outdoor PCB
Troubleshooting
REMARKS:
EEPROM: A read-only memory which contains contents that can be erased and reprogrammed using a pulsed voltage. Review
figures 23 and 24 for the location of the EEPROM chip on the indoor and outdoor PCB.
Fig. 23 — EEPROM Chip (Indoor)
Fig. 24 — EEPROM Chip (Outdoor)
NOTE: For certain models, the outdoor PCB cannot be removed separately. In this case, the outdoor electric control box should be replaced
as a whole. These images are only for reference and the actual appearance may vary.
Shut o the power supply and
turn it on 2 minutes later.
Is it still displaying
the error code ?
YES
Replace the indoor main
PCB (E0)/outdoor main PCB (F4).
Unit is operating as designed.
NO

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18
DIAGNOSIS AND SOLUTION (CONT.)
E1 (Indoor and Outdoor Unit Communication Error Diagnosis and Solution)
Description: Indoor unit cannot communicate with the outdoor unit
Recommended parts to prepare:
• Indoor PCB
• Outdoor PCB
•Reactor
Troubleshooting
For S Communication
Does the error code disappear?
Power o , then restart the unit after 2
minutes.
Measure the DC voltage between N/L2
and S (Black pin to N/L2, Red pin to S).
The value is xed and close
to 0.
The value alternates from
negative to positive.
The value is always positive.
Check the
wiring connection
between the indoor and outdoor
unit. Are they good?
If there is more than 1 PCB,
check the wiring connection
from the outdoor terminal to
the outdoor PCB and the
wiring between PCBs.
Check the wiring connection
from the indoor terminal to the
indoor PCB. Are they good?
Turn on the unit, check if W
and 1 (L) are connected.
Check if the power LED is on.
Yes
Yes
Yes
Unplug electronic expansion valve.
Check if power LED is on.
No
No
Check the AC voltage of L, N
output to IPM board. Is it the
same as the power input?
Check the DC 5V, 12V
from IPM board to main
PCB. Are they normal?
Unplug all the high voltage
components connected to the
main PCB such as 4-way valve, heater,
and AC fan (one by one) to check
their resistance. Has any component
short-circuited?
Yes
No
Unplug electronic expansion valve.
Check if the DC, 5V, 12V to main
PCB are in working order.
Replace the short-circuited
component and the
main PCB.
Replace the electronic
expansion valve coil.
Replace the outdoor PCB. Yes
Yes
Yes
Replace the
main PCB.
No
No
Replace the IPM board.
No
Replace indoor PCB.
No
Solved
Correct the connection or
change wires.
No
No
Yes
For units with a main PCB and IPM board
(both)
For units with only one PCB.
For units with
a W wire
For units without W
wire
No
Replace the short-circuited
component and the
outdoor PCB.
Unplug all the high voltage
components connected to the
main PCB such as 4-way valve, heater,
and AC fan (one by one) to check
their resistance. Has any component
short-circuited?
Yes
Yes
NOTE: For certain models, the outdoor PCB can not be removed separately.
In this case, the outdoor electric control box should be replaced as a whole.

40MBDAQ: Service Manual
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19
DIAGNOSIS AND SOLUTION (CONT.)
Remarks:
• Use a multimeter to test the DC voltage between the 2 port (or S or L2 port) and the 3 port (or N or S port) of the outdoor unit. The red pin
of the multimeter connects with the 2 port (or S or L2 port) while the black pin is for the 3 port (or N or S port).
• When the unit is operating normally, the voltage moves alternately between the positive values and negative values.
• If the outdoor unit malfunctions, the voltage was always the positive value.
• Alternately, if the indoor unit malfunctions, the voltage remains at a fixed value.
• Use a multimeter to test the reactor resistance which does not connect with the capacitor.
• The normal value should be around zero ohm. Otherwise, the reactor must has malfunctioned.

40MBDAQ: Service Manual
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20
DIAGNOSIS AND SOLUTION (CONT.)
For XYE Communication
No
Power o, then restart the unit
2 minutes later.
Adopt shield cable grounding.
No
Yes
Correct the connection.
No
Yes
Remove the interference or
add a magnet ring on the
power wire.
Yes
Yes
Replace the signal wire.
Yes
Pull out and insert back.
No
No
Replace the indoor main PCB.
Is the error distinguished.
Yes
Replace the outdoor main PCB.
No
Check whether there is any
interferance (e.g. too many
lamps or power transformers).
Or is the signal wire too long?
Check whether the signal wire is
shield cable or whether the
shield cable is a ground wire.
Check whether the wire is
correct polarity (P to P, Q to Q, E to E).
Check whether the signal wire is broken.
Check whether the signal wires
are inserted on the PCB rmly.