Mitsubishi Electric MSZ-EF18NAW-U1 User manual

SERVICE MANUAL
INDOOR UNIT
No. OBH736
REVISED EDITION-C
Models
MSZ-EF09NAW -U1 , U2 MSZ-EF12NAW -U1 , U2
MSZ-EF15NAW -U1 , U2 MSZ-EF18NAW -U1 , U2
MSZ-EF09NAB -U1 , U2 MSZ-EF12NAB -U1 , U2
MSZ-EF15NAB -U1 , U2 MSZ-EF18NAB -U1 , U2
MSZ-EF09NAS -U1 , U2 MSZ-EF12NAS -U1 , U2
MSZ-EF15NAS -U1 , U2 MSZ-EF18NAS -U1 , U2
Outdoor unit service manual
MXZ- •C•NA Series (OBH702, OCH573)
MXZ- •C•NAHZ Series (OBH702, CH573)
OBH736 REVISED EDITION-B is void.
Revision C:
• 9-7. TEST POINT DIAGRAM AND
VOLTAGE has been modied.
CONTENTS
1. TECHNICAL CHANGES ······························2
2. PART NAMES AND FUNCTIONS ··················3
3. SPECIFICATION ········································4
4. OUTLINES AND DIMENSIONS ·····················6
5. WIRING DIAGRAM ·····································7
6. REFRIGERANT SYSTEM DIAGRAM ·············8
7. SERVICE FUNCTIONS································9
8. MICROPROCESSOR CONTROL················· 11
9. TROUBLESHOOTING·······························19
10. DISASSEMBLY INSTRUCTIONS·················31
PARTS CATALOG (OBB736)

2
MSZ-EF09NAW - U1 MSZ-EF12NAW - U1 MSZ-EF15NAW - U1 MSZ-EF18NAW - U1
MSZ-EF09NAB - U1 MSZ-EF12NAB - U1 MSZ-EF15NAB - U1 MSZ-EF18NAB - U1
MSZ-EF09NAS - U1 MSZ-EF12NAS - U1 MSZ-EF15NAS - U1 MSZ-EF18NAS - U1
1. New model
MSZ-EF09NAW - U1 MSZ-EF09NAW - U2
MSZ-EF09NAB - U1 MSZ-EF09NAB - U2
MSZ-EF09NAS - U1 MSZ-EF09NAS - U2
MSZ-EF12NAW - U1 MSZ-EF12NAW - U2
MSZ-EF12NAB - U1 MSZ-EF12NAB - U2
MSZ-EF12NAS - U1 MSZ-EF12NAS - U2
MSZ-EF15NAW - U1 MSZ-EF15NAW - U2
MSZ-EF15NAB - U1 MSZ-EF15NAB - U2
MSZ-EF15NAS - U1 MSZ-EF15NAS - U2
MSZ-EF18NAW - U1 MSZ-EF18NAW - U2
MSZ-EF18NAB - U1 MSZ-EF18NAB - U2
MSZ-EF18NAS - U1 MSZ-EF18NAS - U2
1. Model name has been changed.
Revision A:
• 4. OUTLINES AND DIMENTIONS has been modified.
• Some descriptions have been modified.
Revision B:
• MSZ-EF09/12/15/18NAW/B/S-U2 have been added.
Use the specied refrigerant only
Never use any refrigerant other than that specified.
Doing so may cause a burst, an explosion, or fire when the unit is being used, serviced, or disposed of.
Correct refrigerant is specified in the manuals and on the spec labels provided with our products.
We will not be held responsible for mechanical failure, system malfunction, unit breakdown or accidents caused by failure to
follow the instructions.
<Preparation before the repair service>
Prepare the proper tools.
Prepare the proper protectors.
Provide adequate ventilation.
After stopping the operation of the air conditioner, turn off the power-supply breaker and pull the power plug.
Discharge the capacitor before the work involving the electric parts.
<Precautions during the repair service>
Do not perform the work involving the electric parts with wet hands.
Do not pour water into the electric parts.
Do not touch the refrigerant.
Do not touch the hot or cold areas in the refrigeration cycle.
When the repair or the inspection of the circuit needs to be done without turning off the power, exercise great caution not to
touch the live parts.
WARNING
• When the refrigeration circuit has a leak, do not execute pump down with the compressor.
• When pumping down the refrigerant, stop the compressor before disconnecting the refrigerant pipes.
The compressor may burst if air etc. get into it.
• When opening or closing the valve below freezing temperatures, refrigerant may spurt out from the gap
between the valve stem and the valve body, resulting in injuries.
Revision C:
• 9-7. TEST POINT DIAGRAM AND VOLTAGE has been modied.
1 TECHNICAL CHANGES
OBH736C

3
PART NAMES AND FUNCTIONS2
MSZ-EF09NAW MSZ-EF12NAW MSZ-EF15NAW MSZ-EF18NAW
MSZ-EF09NAB MSZ-EF12NAB MSZ-EF15NAB MSZ-EF18NAB
MSZ-EF09NAS MSZ-EF12NAS MSZ-EF15NAS MSZ-EF18NAS
ACCESSORIES
Model
MSZ-EF09NAW MSZ-EF12NAW MSZ-EF15NAW MSZ-EF18NAW
MSZ-EF09NAB MSZ-EF12NAB MSZ-EF15NAB MSZ-EF18NAB
MSZ-EF09NAS MSZ-EF12NAS MSZ-EF15NAS MSZ-EF18NAS
Installation plate 1
Installation plate xing screw 4 × 25 mm 5
Remote controller holder 1
Fixing screw for 3.5 × 16 mm (Black) 2
Battery (AAA) for remote controller 2
Wireless remote controller 1
Felt tape (For left or left-rear piping) 1
Soft dry cloth (NAB type only) 1
Air cleaning lter 2
Remote controller
Operation
indicator lamp
Remote control
receiving section
Emergency
operation switch
Horizontal vane
Air inlet
Air filter
(Nano platinum filter)
Air cleaning filter
(Electrostatic anti-allergy
enzyme filter)
Heat exchanger
Front panel
Air outlet
OBH736C

4
3 SPECIFICATION
3-1. OPERATING RANGE
(1) POWER SUPPLY
Rated voltage Guaranteed voltage (V)
Indoor unit
208/230 V
1 phase
60 Hz
Min. 187 208 230 Max. 253
(2) OPERATION
Mode Condition
Intake air temperature (°F)
Indoor Outdoor
DB WB DB WB
Cooling
Standard temperature 80 67 95 —
Maximum temperature 90 73 115 —
Minimum temperature 67 57 14 —
Maximum humidity 78% —
Heating
Standard temperature 70 60 47 43
Maximum temperature 80 67 75 65
Minimum temperature 70 60 -13 -14
Indoor unit model MSZ-EF09NAW
MSZ-EF09NAB
MSZ-EF09NAS
MSZ-EF12NAW
MSZ-EF12NAB
MSZ-EF12NAS
MSZ-EF15NAW
MSZ-EF15NAB
MSZ-EF15NAS
MSZ-EF18NAW
MSZ-EF18NAB
MSZ-EF18NAS
Power supply V, phase, Hz 208/230 , 1 , 60
Disconnect switch A 15
Min. circuit ampacity A 1.0
Fan motor F.L.A 0.67
Airow
Super high - High - Med. - Low - Quiet
COOL Dry
(Wet) CFM
371 - 293 - 222 - 162 - 141
(319 - 252 - 191 - 140 - 121)
371 - 293 - 222 - 162 - 141
(319 - 252 - 191 - 140 - 121)
364 - 314 - 272 - 233 - 205
(313 - 270 - 234 - 200 - 176)
388 - 328 - 279 - 240 - 205
(334 - 282 - 240 - 206 - 176)
HEAT Dry CFM 420 - 314 - 219 - 162 - 141 448 - 314 - 219 - 162 - 141 448 - 350 - 275 - 222 - 194 466 - 392 - 318 - 258 - 226
Moisture removal pt./h 0.6 2.1 3.6 4.4
Sound level
Super high - High - Med. - Low - Quiet
Cooling dB(A)
42 - 36 - 29 - 23 - 21 42 - 36 - 29 - 24 - 21 42 - 39 - 35 - 31 - 28 43 - 40 - 36 - 33 - 30
Heating dB(A) 45 - 37 - 29 - 24 - 21 46 - 38 - 30 - 24 - 21 48 - 41 - 35 - 30 - 28 49 - 43 - 37 - 33 - 30
Cond. drain connection O.D. in. 5/8
Dimensions
W
in.
34-13/16
D 7-11/16
H 11-3/4
Weight Ib. 26
External nish
W: Munsell 1.0Y 9.2/0.2
B: Munsell 3.7PB 2.0/0.1
S: Munsell 3.1PB 8.2/0.2
Remote controller Wireless type
Control voltage (by built-in transformer) 12 - 24 V DC
NOTE: Test conditions are based on AHRI 210/240.
OBH736C

5
3-2. OUTLET AIR SPEED AND COVERAGE
● The air coverage is the figure up to the
position where the air speed is 1 ft./s,
when air is blown out horizontally from
the unit properly at the High speed
position.
The coverage should be used only
as a general guideline since it varies
according to the size of the room and
furniture arranged inside the room.
Model Mode Function Airow
(CFM)
Air speed
(ft./s)
Coverage
(ft.)
MSZ-EF09NAW
MSZ-EF09NAB
MSZ-EF09NAS
HEAT Dry 420 19.5 29.2
COOL Dry 371 17.2 25.8
Wet 319 15.5 23.3
MSZ-EF12NAW
MSZ-EF12NAB
MSZ-EF12NAS
HEAT Dry 448 20.8 31.1
COOL Dry 371 17.2 25.8
Wet 319 15.5 23.3
MSZ-EF15NAW
MSZ-EF15NAB
MSZ-EF15NAS
HEAT Dry 448 20.8 31.1
COOL Dry 364 16.8 25.4
Wet 313 15.2 22.9
MSZ-EF18NAW
MSZ-EF18NAB
MSZ-EF18NAS
HEAT Dry 466 21.6 32.3
COOL Dry 388 20.3 30.4
Wet 336 18.3 27.4
OBH736C

6
4OUTLINES AND DIMENSIONS
Unit: inch
MSZ-EF09NAW MSZ-EF12NAW MSZ-EF15NAW MSZ-EF18NAW
MSZ-EF09NAB MSZ-EF12NAB MSZ-EF15NAB MSZ-EF18NAB
MSZ-EF09NAS MSZ-EF12NAS MSZ-EF15NAS MSZ-EF18NAS
2-3/8
7-5/8
11/16
3-3/8
2-3/16
1-15/16
2-13/16
8-7/8
8-7/8
7-1/16 7-1/16
10-1/16
10
3-1/4
3-1/4
8-3/8
9-1/8 7/8
1-3/4
1/4
9-3/161-3/4
2-7/16 2-15/1614-15/16 14-1/2
34-13/16
34-7/16 3/16
9-13/16
7-11/163/16
2-13/16
1-7/8
26-11/16 6
(80 )
1/4
3-15/16
4-5/16
3-11/16
2-3/16
2-5/16
11-3/4
(2-1/8)
Air out
Installation plate
Piping
Drain hose
7/16 × 1 Oblong hole
7/16 × 13/16 Oblong hole
Installation plate
Indoor unit
Wall hole Φ 2-15/16
Air in
In case of left, left back,or left under piping (using spacer),
4-3/8 or more.
1/4 or more
2-1/4 or more
1-3/8 or more
1 or more
MSZ-EF09/12NA MSZ-EF15/18NA
OBH736C

7
WIRING DIAGRAM5
MSZ-EF09NAW MSZ-EF12NAW MSZ-EF15NAW MSZ-EF18NAW
MSZ-EF09NAB MSZ-EF12NAB MSZ-EF15NAB MSZ-EF18NAB
MSZ-EF09NAS MSZ-EF12NAS MSZ-EF15NAS MSZ-EF18NAS
OBH736C

8
6 REFRIGERANT SYSTEM DIAGRAM
Unit: inch (mm)
MSZ-EF09NAW MSZ-EF12NAW MSZ-EF15NAW MSZ-EF18NAW
MSZ-EF09NAB MSZ-EF12NAB MSZ-EF15NAB MSZ-EF18NAB
MSZ-EF09NAS MSZ-EF12NAS MSZ-EF15NAS MSZ-EF18NAS
Indoor
heat
exchanger
Flared connection
Room temperature
thermistor
RT11
Flared connection
Refrigerant pipe ø3/8 (ø9.52) (MSZ-EF09/12)
ø1/2 (ø12.7) (MSZ-EF15/18
)
(with heat insulator)
Refrigerant pipe ø1/4 (ø6.35)
(with heat insulator)
Indoor coil
thermistor
RT12 (main)
Indoor coil
thermistor
RT13 (sub)
Refrigerant flow in cooling
Refrigerant flow in heating
OBH736C

9
SERVICE FUNCTIONS7
7-1. TIMER SHORT MODE
For service, the following set time can be shortened by bridging JPG and JPS on the electronic control P.C. board.
(Refer to 9-7.)
• The set time for the ON/OFF timer can be reduced to 1 second for each minutes.
• After the breaker is turned on, the time for starting the compressor, which normally takes 3 minuets, can be reduced to
3 seconds. Restarting the compressor, which takes 3 minuets, cannot be reduced.
7-2. HOW TO SET REMOTE CONTROLLER EXCLUSIVELY FOR A PARTICULAR INDOOR UNIT
A maximum of 4 indoor units with wireless remote controllers can be used in a room.
To operate the indoor units individually with each remote controller, assign a number to each remote controller according to
the number of the indoor unit.
This setting can be set only when all the following conditions are met:
• The remote controller is powered OFF.
• Weekly timer is not set.
• Weekly timer is not being edited.
(1) Hold down button on the remote controller for 2 seconds to enter the pairing mode.
(2) Press button again and assign a number to each remote controller.
Each press of button advances the number in the following order: 1 → 2 → 3 → 4.
(3) Press button to complete the pairing setting.
After you turn the breaker ON, the remote controller that first sends a signal to an indoor unit will be regarded as the
remote controller for the indoor unit.
Once they are set, the indoor unit will only receive the signal from the assigned remote controller afterwards.
MSZ-EF09NAW MSZ-EF12NAW MSZ-EF15NAW MSZ-EF18NAW
MSZ-EF09NAB MSZ-EF12NAB MSZ-EF15NAB MSZ-EF18NAB
MSZ-EF09NAS MSZ-EF12NAS MSZ-EF15NAS MSZ-EF18NAS
OBH736C

10
7-3. AUTO RESTART FUNCTION
When the indoor unit is controlled with the remote controller, the operation mode, the set temperature, and the fan speed
are memorized by the indoor electronic control P.C. board. “AUTO RESTART FUNCTION” automatically starts operation in
the same mode just before the shutoff of the main power.
Operation
If the main power has been cut, the operation settings remain.
After the power is restored, the unit restarts automatically according to the memory.
(However, it takes at least 3 minutes for the compressor to start running.)
How to disable “AUTO RESTART FUNCTION”
Turn off the main power for the unit.
Cut the jumper wire to JR77 on the indoor electronic control P.C. board. (Refer to 9-7.)
NOTE:
• The operation settings are memorized when 10 seconds have passed after the indoor unit was operated with the remote
controller.
• If main power is turned OFF or a power failure occurs while AUTO START/STOP timer is active, the timer setting is can-
celled.
• If the unit has been off with the remote controller before power failure, the auto restart function does not work as the power
button of the remote controller is OFF.
• To prevent breaker OFF due to the rush of starting current, systematize other home appliance not to turn ON at the same
time.
• When some air conditioners are connected to the same supply system, if they are operated before power failure, the start-
ing current of all the compressors may flow simultaneously at restart.
Therefore, the special counter-measures are required to prevent the main voltage-drop or the rush of the starting current
by adding to the system that allows the units to start one by one.
JR77
IC171
CN104CN112
BZ
Indoor electronic
control P.C. board
OBH736C