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TROUBLESHOOTING

20

10

10-1. Cautions on troubleshooting

1. Before troubleshooting, check the following:
(1) Check the power supply voltage.
(2) Check the indoor/outdoor connecting wire for mis-wiring.
2. Take care the following during servicing.

(1) Before servicing the air conditioner, be sure to first turn off the remote controller to stop the main unit, and then after

confirming the horizontal vane is closed, turn off the breaker and / or disconnect the power plug.

(2) Be sure to turn OFF the power supply before removing the front panel, the cabinet, the top panel, and the electronic

control P.C. board.

(3) When removing the electronic control P.C. board, hold the edge of the board with care NOT to apply stress on the

components.

(4) When connecting or disconnecting the connectors, hold the housing of the connector. DO NOT pull the lead wires.

3. Troubleshooting procedure

(1) First, check if the OPERATION INDICATOR lamp on the indoor unit is flashing on and off to indicate an abnormality.

To make sure, check how many times the abnormality indication is flashing on and off before starting service work.

(2) Before servicing check that the connector and terminal are connected properly.
(3) If the electronic control P.C. board is supposed to be defective, check the copper foil pattern for disconnection and the

components for bursting and discolouration.

(4) When troubleshooting, refer to the flow chart on page 21 and the check table on page 22.

4. How to replace batteries

Weak batteries may cause the remote controller malfunction.
In this case, replace the batteries to operate the remote controller normally.

1

Remove the front lid and insert batteries.

Then reattach the front lid.

Lead wiring

Housing point

NOTE2. INFORMATION FOR MULTI SYSTEM AIR CONDITIONER 

(OUTDOOR UNIT : MXZ-A18WV-

MXZ-A26WV-

MXZ-A32WV-

)

Multi system air conditioner (Outdoor unit MXZ-A18WV-

MXZ-A26WV-

MXZ-A32WV-

) can connect two or

more indoor units with one outdoor unit. 
According to the capacity, two or more units can operate simultaneously.

•When you try to operate two or more indoor units with one outdoor unit simultaneously, one for the cooling and the

other for heating, the operation mode of the indoor unit that operates earlier is selected. The other indoor units that
will start the operation later cannot operate, indicating as shown in the figure below. In this case, please set all the
indoor units to the same operation mode.

•When indoor units starts the operation while the defrosting of outdoor unit is being done, it takes a few minutes

(max. 10 minutes) to blow out the warm air.

•In the heating operation, though indoor unit that does not operate may get warm or the sound of refrigerant flowing

may be heard, they are not malfunction. The reason is that the refrigerant continuously flows into it.

E1

E1

E1

E1

E1

E1

lighted

flashing

Operation Indicator

NOTE1. : 1. If the RESET button is not pressed, the remote controller may not operate correctly.

MSH-A18WV  -
MSH-A24WV  -
MSH-A30WV  -

E1

E1

E1

RESET button

Insert the negative pole 
of the batteries first.
Check if the polarity of 
the battereis is correct.

2

Press the RESET button with tip end of ball point 
pen or the like, and then use the remote controller.

OB321-1.qxp  03.11.13 4:03 PM  Page 20

Summary of Contents for MSH-A18WV

Page 1: ...H A30WV WH E1 E1 E1 No OB321 SPLIT TYPE HEAT PUMP AIR CONDITIONERS MSH A18WV MSH A24WV MSH A30WV E1 E1 E1 NOTE This service manual describes technical data of the indoor unit Refer to the service manu...

Page 2: ...aning filter has changed to catechin air filter MSH 24RV MSH A24WV 1 Indoor unit model has changed 2 Rated voltage has changed 220V 240V 230V 3 Remote controller has changed LONG MODE and WIDE MODE ha...

Page 3: ...n the front lid Signal transmitting section Operation display section OPERATE STOP ON OFF button TEMPERATURE buttons OPERATION SELECT button FAN SPEED CONTROL button OFF TIMER button HR button MIN but...

Page 4: ...oor DB35 C WB 24 C Outdoor DB 7 C WB 6 C Indoor Outdoor piping length 5m w Reference value Indoor model Function Power supply Air flow High Med Low Power outlet Running current Power input Auxiliary h...

Page 5: ...FREQUENCIES Hz Test conditions Cooling Dry bulb temperature 27 Wet bulb temperature 19 APPROXIMATE THRESHOLD OF HEARING FOR CONTINUOUS NOISE 42 SPL dB A LINE High FAN SPEED Heating Dry bulb temperatu...

Page 6: ...art O D Liquid line 6 35 0 5m Gas line 12 0 43m Insulation 50 O D 32 I D Installation plate Wall hole 75 Wireless remote controller Installation plate Indoor unit Liquid line 9 52 0 5m Gas line 12 0 4...

Page 7: ...U PE BRN TO OUTDOOR UNIT CONNECTING 12V 1 2 3 4 5 6 CIRCUIT BREAKER POWER SUPPLY CORD N 230V 50Hz INDOOR UNIT 12V TO OUTDOOR UNIT CONNECTING BRN BLU GRN YLW BLK GRY YLW BRN WHT RED MF 3 SR141 4 3 1 CN...

Page 8: ...n cooling Refrigerant flow in heating MSH A18WV E1 INDOOR UNIT Indoor heat exchanger Room temperature thermistor RT11 Refrigerant pipe 12 7 with heat insulator Flared connection Flared connection Indo...

Page 9: ...HEAT DRY PM CLOCK AM RESET CLOCK OPERATION SELECT button FAN SPEED CONTROL button OFF TIMER button HR button MIN button TIME SET button ON TIMER button RESET button ECONO COOL button VANE button Hori...

Page 10: ...temperature minus 2 Initial room temperature minus 2 1 4 The initial set temperature is decided by the initial room temperature 1 When the system is restarted with the remote controller the system op...

Page 11: ...or below MSH A24WV RT12 or RT13 reads 1 C or below MSH A30WV the coil frost prevention mode starts immediately However the coil frost prevention doesn t work for 5 minutes since the compressor has st...

Page 12: ...sting this control works 3 Warm air control When compressor starts in heating operation or after defrosting the fan changes the speed due to the indoor coil ther mistor RT12 temperature to blow out wa...

Page 13: ...RATE STOP ON OFF button OPERATION INDICATOR lamp of the indoor unit turns on with a beep tone 2 Select COOL mode with the OPERATION SELECT button 3 Press the TEMPERATURE buttons TOO WARM or TOO COOL b...

Page 14: ...timum room temperature distribution 5 STOP operation OFF and ON TIMER standby When the following cases occur the horizontal vane returns to the closed position a When the OPERATE STOP ON OFF button is...

Page 15: ...lled when the ECONO COOL button is pressed once again or VANE button is pressed or LONG button is pressed or change to other operation mode NOTE ECONO COOL operation does not work in COOL mode of I FE...

Page 16: ...operation and HEAT operation W Indoor fan speed becomes faster than setting fan speed on the remote controller even when or is selected COOL and DRY HEAT About 100 About 150 Horizontal AIR FLOW blowi...

Page 17: ...ed The coil frost prevention works even in emergency operation and defrosting too In the test run or emergency operation the horizontal vane operates in VANE AUTO mode Emergency operation continues un...

Page 18: ...ove batteries before modification The board has a print as shown below 9 1 TIMER SHORT MODE For service set time can be shortened by short circuit of JPG and JPS on the electronic control P C board Th...

Page 19: ...ter the remote controller 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 cancelled If the unit...

Page 20: ...the remote controller malfunction In this case replace the batteries to operate the remote controller normally 1 Remove the front lid and insert batteries Then reattach the front lid Lead wiring Hous...

Page 21: ...mis wiring When outdoor unit doesn t work on page 26 Check room temperature thermistor and indoor coil thermis tor Refer to Test point diagram and voltage on page 27 Refer to A Check of indoor fan mot...

Page 22: ...ly 5 minutes the compressor stops operation Abnormal point Outdoor unit does not operate Room temperature thermistor 2 time flash 2 5 second OFF Detect Indoor coil room temperature thermistor short or...

Page 23: ...RT13 sub Horizontal vane motor MV1 Vertical vane motor MV2 Motor part Sensor part Measure the resistance between the terminals with a tester Part temperature 10 C 30 C Color of lead wire BRN YLW YLW G...

Page 24: ...voltage between receiver P C board connector CN301 No 1 and No 3 when the remote controller button is pressed Is the voltage approx 4V DC Replace the indoor electronic control P C board Replace the re...

Page 25: ...Replace the varistor Yes Turn OFF the power supply Remove indoor fan motor connector CN211 and vane motor connector CN151 from the indoor electronic control P C board and turn ON the power supply No...

Page 26: ...s mis wiring poor contact or wire disconnection Make them sure Replace the indoor electronic control P C board Is there 230V AC between L N on the outdoor terminal block No Check the outdoor power sup...

Page 27: ...DC Indoor coil thermistor RT12 main Timer short mode point JPS JPG Refer to page 18 Emergency operation switch 12V DC Indoor coil thermistor RT12 main RT13 sub Room temperature thermistor RT11 Resist...

Page 28: ...caps of the front panel Remove the screws 2 Pull the panel down to your side slightly and unhook the catches at the top Photo 1 Photo 2 Front panel Screw of the V A clamp Indoor electronic control P C...

Page 29: ...drain hose from the nozzle assembly and remove the nozzle assembly 6 Remove the screws of the vane motor and disconnect the connector 7 Remove the vane motor Screws fixing the fan motor 5 Removing th...

Page 30: ...ng Diagram Q ty unit Including No 4 5 6 4PCS SET 3PCS SET Remarks Part No NO Part Name 1 2 3 4 5 6 7 8 9 1 1 1 4 3 1 2 1 1 1 1 1 4 3 1 2 1 1 1 1 1 4 3 1 2 1 1 12 2 INDOOR UNIT HEAT EXCHANGER 2 4 5 7 6...

Page 31: ...ERMISTOR VANE MOTOR SUPPORT SET RIGHT VANE MOTOR SUPPORT SET LEFT Symbol in Wiring Diagram Q ty unit 3 15A RIGHT LEFT UP DOWN Remarks Part No NO Part Name F11 NR11 MF MF MV2 MV1 RT11 TB RT12 RT12 RT13...

Page 32: ...llows type AIR CLEANING FILTER AIR CLEANING FILTER removes fine dust of 0 01 micron from air by means of static electricity Normal life of AIR CLEANING FILTER is 4 months However when it becomes dirty...

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