Mitsubishi Electric MS-GF20VA - E1 Service Manual Download Page 24

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MS-GF20VA MS-GF25VA MS-GF35VA

10-7. TEST POINT DIAGRAM AND VOLTAGE

1. Indoor electronic control P.C. board

Room temperature thermistor RT11 (CN111)

Indoor coil thermistor RT12 (CN112)

GND

Vane motor (CN151)

Connector to
Indoor power P.C.
board (CN10A)

12 VDC

5 VDC

Timer short mode point

JPG, JPS (Refer to 8-1.)

Emergency operation
switch (E.O. SW) (SW1)

To disable" Auto restart function", solder
the Jumper wire to JR07 (Refer to 8-3.)

Indoor coil thermistor (RT12)
Room temperature thermistor (RT11)

Temperature (°C)

Resistance (k

)

2. Indoor terminal P.C. board Indoor power P.C. board

}

Indoor fan motor
(CN211)
230 V AC

Please replace the fuse after removing the indoor terminal P.C. board from the electrical box.

Fuse (F11)( )

Connector to indoor electronic
control P.C. board (CN20A)

12 VDC

GND

5 VDC

Terminal
block

CN121

Varistor (NR11)

R111

Indoor Power P.C. board

Indoor terminal P.C. board

OBH621

Summary of Contents for MS-GF20VA - E1

Page 1: ...SYSTEM DIAGRAM 7 8 SERVICE FUNCTIONS 8 9 MICROPROCESSOR CONTROL 10 10 TROUBLESHOOTING 15 11 DISASSEMBLY INSTRUCTIONS 25 SPLIT TYPE AIR CONDITIONERS Outdoor unit service manual MU GF VA Series OBH622 SERVICE MANUAL No OBH621 INDOOR UNIT PARTS CATALOG OBB621 NOTE RoHS compliant products have G mark on the spec name plate Models MS GF20VA E1 MS GF25VA E1 MS GF35VA E1 ...

Page 2: ...tions 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 remove 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 ...

Page 3: ...r remote controller 2 Wireless remote controller 1 Felt tape For left or left rear piping 1 MS GF20VA MS GF25VA MS GF35VA Air filter Nano platinum filter Front panel Air cleaning filter Electrostatic anti allergy enzyme filter option Operation indicator lamp Remote control receiving section Emergency operation switch E O SW Horizontal vane Air outlet Heat exchanger Display section Air inlet Remote...

Page 4: ...ction 5 Airfl ow Super High POWERFUL m 3 h 558 624 High 474 558 Med 378 396 Low 246 288 Sound level Super High POWERFUL dB A 40 44 High 36 40 Med 31 33 Low 25 26 Fan speed Super High POWERFUL rpm 1 000 1 100 High 880 1 000 Med 740 770 Low 540 610 Fan speed regulator 4 Remote controller model KM12A NOTE Test conditions are based on ISO 5151 Cooling Indoor Dry bulb temperature 27 Wet bulb temperatur...

Page 5: ...TER FREQUENCIES Hz COOLING FUNCTION SPL dB A LINE Super High FAN SPEED 40 NC 10 OCTAVE BAND SOUND PRESSURE LEVEL 0dB re 0 0002 MICRO BAR Test conditions Cooling Dry bulb temperature 27 C Wet bulb temperature 19 C INDOOR UNIT WALL MICROPHONE 0 8m 1m 90 80 70 60 50 40 30 20 10 63 125 250 500 1000 2000 4000 8000 NC 60 NC 50 NC 40 NC 30 NC 20 NC 70 BAND CENTER FREQUENCIES Hz COOLING FUNCTION SPL dB A ...

Page 6: ...26 Oblong hole 11 20 Oblong hole Installation plate Indoor unit Wall hole ø65 Air in Air out Installation plate Piping Drain hose 159 19 58 MS GF20VA MS GF25VA MS GF35VA Piping Insulation ø35 O D Liquid line ø7 0 5 m Flared connection ø6 35 Gas line ø9 52 0 43 m Flared connection ø9 52 Drain hose Insulation ø28 O D Connected part ø16 O D WIRING DIAGRAM 6 MS GF20VA MS GF25VA MS GF35VA OBH621 ...

Page 7: ... 35 with heat insulator Indoor coil thermistor RT12 Refrigerant flow in cooling Refrigerant pipe 9 52 with heat insulator MS GF35VA Indoor heat exchanger Flared connection Room temperature thermistor RT11 Flared connection Refrigerant pipe 6 35 with heat insulator Indoor coil thermistor RT12 Refrigerant flow in cooling Refrigerant pipe 9 52 with heat insulator OBH621 ...

Page 8: ...ut back the batteries then press the RESET button J2 J1 Table 1 1 unit operation 2 units operation 3 units operation 4 units operation No 1 unit No modification Same as at left Same as at left Same as at left No 2 unit Solder J1 Same as at left Same as at left No 3 unit Solder J2 Same as at left No 4 unit Solder both J1 and J2 How to set the remote controller exclusively for particular indoor unit...

Page 9: ...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...

Page 10: ...cation Indication Operation state Room temperature The unit is operating to reach the set temperature About 2 C or more away from set temperature The room temperature is approaching the set tem perature About 1 to 2 C from set temperature INDOOR UNIT DISPLAY SECTION Lighted Blinking Not lighted 9 1 COOL OPERATION 1 Press OPERATE STOP ON OFF button OPERATION INDICATOR lamp of the indoor unit turns ...

Page 11: ... OPERATION INDICATOR lamp of the indoor unit turns ON with a beep tone 2 Select I FEEL CONTROL mode with the OPERATION SELECT button 3 The operation mode is determined by the room temperature at start up of the operation Once the mode is fixed the mode does not change by room temperature afterwards Under ON TIMER operation mode is determined as follows When the system is stopped by the remote cont...

Page 12: ...nsidering the room temperature the frequency of pressing TOO COOL or TOO WARM button and the user s preference to heat or cold So this is called Fuzzy control and works only in I FEEL CONTROL mode In DRY mode of I FEEL CONTROL the set temperature does not change To raise the set temperature 1 2 To lower the set temperature 1 2 9 5 AUTO VANE OPERATION 1 Horizontal vane 1 Vane motor drive These mode...

Page 13: ...tion During COOL or DRY operation with the vane angle at Angle 4 or 5 when the compressor cumulative operation time exceeds 1 hour the vane angle automatically changes to Angle 1 for dew prevention 1 How to set the time 1 Check that the current time is set correctly NOTE Timer operation will not work without setting the current time Initially 0 00 blinks at the current time display of TIME MONITOR...

Page 14: ...l light The first 30 minutes of operation is the test run operation This opera tion is for servicing The indoor fan runs at High speed and the tem perature control does not work After 30 minutes of test run operation the system shifts to EMERGENCY COOL MODE with a set temperature of 24 C The fan speed shifts to Med The coil frost prevention works even in the test run or the emergency operation In ...

Page 15: ...starting service work 2 Before servicing check that the connector and terminal are connected properly 3 When the electronic control P C board seems to be defective check the copper foil pattern for disconnection and the components for bursting and discoloration 4 When troubleshooting Refer to 10 2 10 3 and 10 4 4 How to replace batteries Weak batteries may cause the remote controller malfunction I...

Page 16: ...f the remote controller the set temperature is displayed with the remote controller headed towards the indoor unit Press EMERGENCY OPERATION switch so that the memorized abnormal condition is deleted Release the failure mode recall function according to Releasing the failure mode recall function mentioned above Yes Blinks No OFF NOTE 1 Make sure to release the failure mode recall function once it ...

Page 17: ...ime flash 2 5 second OFF Indoor fan motor The rotational frequency feedback signal is not emitted for 12 seconds after the indoor fan motor is operated Refer to 10 6 Check of indoor fan motor 12 time flash 2 5 second OFF Indoor control system It cannot properly read data in the nonvolatile memory of the indoor electronic control P C board Replace the indoor electronic control P C board 14 time fla...

Page 18: ...room temperature indoor coil thermistor Upper lamp 3 time flash Cause Indoor unit Trouble of indoor fan motor Upper lamp 4 time flash Cause Indoor unit Trouble of indoor unit control system Start Check room temperature thermistor and indoor coil thermis tor Refer to 10 7 Test point diagram and voltage Refer to 10 6 Check of indoor fan motor Replace the indoor elec tronic control P C board Outdoor ...

Page 19: ...r con trol system Upper lamp flashes 4 time flash 2 5 second OFF It cannot properly read data in the nonvolatile memory of the indoor electronic control P C board Replace the indoor electronic control P C board 4 1 Refrigerant circuit Upper lamp flashes 14 time flash 2 5 second OFF The unit has been pumped down for a long time Check the stop valve The refrigerant amount is low Check the connection...

Page 20: ... Indoor power P C board Fuse F11 Indoor terminal P C board Varistor NR11 CN121 Are soldered points of the connector correctly soldered to the indoor power P C board Is the resistance 0 short circuit or open circuit Yes 0 or Yes Pay enough attention to the high voltage on the fan motor connector No Yes No Turn OFF the power supply Check connector CN211 visually Disconnect lead wires from connector ...

Page 21: ...remote controller visible Remove the batteries then set them back and press RESET button Refer to 10 1 4 Check if the unit operates with the remote controller Yes No Turn ON a radio to AM and press OP ERATE STOP ON OFF button on the remote controller Is noise heard from radio Yes No Replace the remote controller Are there any fluorescent lights of inverter or rapid start type within the range of 1...

Page 22: ...1 Are the varistor NR11 burnt and the fuse F11 blown Be sure to check both the fuse and the varistor in any case No Yes No Is the fuse F11 blown only Yes No Is there approximately 5 VDC between 5 VDC and JPG GND of the indoor electronic control P C board Is there approximately 9 VDC to 13 VDC between 12 VDC and JPG GND of the indoor electronic control P C board Replace the fuse F11 1 Replace the f...

Page 23: ...he installation condition combination of specific conditions such as antennas or wiring Check the following before asking for service 1 Devices affected by the electromagnetic noise TV sets radios FM AM broadcast shortwave 2 Channel frequency broadcast station affected by the electromagnetic noise 3 Channel frequency broadcast station unaffected by the electromagnetic noise 4 Layout of indoor outd...

Page 24: ...E O SW SW1 To disable Auto restart function solder the Jumper wire to JR07 Refer to 8 3 Indoor coil thermistor RT12 Room temperature thermistor RT11 Temperature C Resistance kΩ 2 Indoor terminal P C board Indoor power P C board Indoor fan motor CN211 230 V AC Please replace the fuse after removing the indoor terminal P C board from the electrical box Fuse F11 Connector to indoor electronic control...

Page 25: ...is a locking lever or not 2 The terminal with this connector has the locking mechanism Slide the sleeve Pull the terminal while pushing the locking lever Hold the sleeve and pull out the terminal slowly Connector Sleeve Locking lever Terminal with locking mechanism Detaching points The terminal which has the locking mechanism can be detached as shown below There are two types refer to 1 and 2 of t...

Page 26: ...r electronic con trol P C board 10 Remove the room temperature thermistor from the indoor electronic control P C board Photo 2 Photo 3 3 Remove the indoor power P C board the indoor terminal P C board and the electrical box 1 Remove the panel Refer to 1 and the corner box 2 Remove the indoor outdoor connecting wire Refer to 2 2 4 3 Remove the earth wire connected to the indoor heat exchanger from ...

Page 27: ...the drain hose from the nozzle assembly and remove the nozzle assembly Photo 4 5 Removing the horizontal vane motor 1 Remove the nozzle assembly Refer to 4 2 Remove the screws of the horizontal vane motor unit 3 Disconnect the connector from the horizontal vane motor 4 Remove the screws of the horizontal vane motor 5 Remove the horizontal vane motor from the horizontal vane motor unit 27 Screws of...

Page 28: ... indoor coil thermistor from the heat exchanger Install the indoor coil thermistor in its former position when assembling it Refer to Photo 8 9 Remove the screws fixing the left side of the heat exchanger 10 Lift the heat exchanger and pull out the line flow fan to the lower left Photo 8 Photo 5 Photo 6 Photo 7 Screw of the line flow fan Screws of the motor bed Motor band Indoor coil thermistor ma...

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