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SERVICE TECHNICAL GUIDE

CONTENTS

 1. MSC/MS/MSH MICROPROCESSOR CONTROL · 4
 2. MSZ/MLZ MICROPROCESSOR CONTROL ·······11

SPLIT-TYPE AIR CONDITIONERS

No. OBT17

REVISED EDITION-D

Revision D:

 •MSC-GE·VB-

E

, MS-GE·VB-

E

, MSH-

GE·VB-

E

, MUZ-FD50VA -

E

, MSZ-GE42/

50VA -

E

 

and MSZ-CGE42/50VA -

E

 

have 

been added.

Please void OBT17 REVISED EDITION-C.

CONFIDENTIAL
(FOR INTERNAL USE ONLY)

Models

MSC-GE•VB - 

E

MS-GD•VB - 

E

· MU-GD•VB - 

E

MS-GE•VB - 

E

· MU-GE•VB - 

E

MSH-GD•VB - 

E

· MUH-GD•VB - 

E

MSH-GE•VB - 

E

· MUH-GE•VB - 

E

MSZ-GC•VA - 

E

· MUZ-GC•VA(H) - 

E

MSZ-HC•VA(B) - 

E

· MUZ-HC•VA(B) - 

E

MSZ-CHC•VA - 

E

MSZ-FD•VA(S) - 

E

· MUZ-FD•VA(H)(BH) - 

E

MSZ-GE•VA - 

E

· MUZ-GE•VA(H) - 

E

MSZ-CGE•VA - 

E

MLZ-KA•VA - 

E

Summary of Contents for MS-GD-VB - E

Page 1: ...E VB E MUZ FD50VA E MSZ GE42 50VA E and MSZ CGE42 50VA E have been added Please void OBT17 REVISED EDITION C CONFIDENTIAL FOR INTERNAL USE ONLY Models MSC GE VB E MS GD VB E MU GD VB E MS GE VB E MU GE VB E MSH GD VB E MUH GD VB E MSH GE VB E MUH GE VB E MSZ GC VA E MUZ GC VA H E MSZ HC VA B E MUZ HC VA B E MSZ CHC VA E MSZ FD VA S E MUZ FD VA H BH E MSZ GE VA E MUZ GE VA H E MSZ CGE VA E MLZ KA V...

Page 2: ...ision B MS GD VB E and MSH GD VB E have been added Revision C MSZ FD50VA E MSZ GE VA E MSZ CHC VA E and MSZ CGE VA E have been added Revision D MSC GE VB E MS GE VB E MSH GE VB E MUZ FD50VA E MSZ GE42 50VA E and MSZ CGE42 50VA E have been added ...

Page 3: ...UMP FLOAT SENSOR CONTROL 16 2 8 INVERTER SYSTEM CONTROL 17 2 9 OPERATIONAL FREQUENCY CONTROL OF OUTDOOR UNIT 20 2 10 PRE HEAT CONTROL 21 2 11 EXPANSION VALVE CONTROL LEV CONTROL 22 NOTE As for the multi system type models or MU MUH GA type models refer to the appropriate service technical guide as well as this service technical guide 1 MSC MS MSH MICROPROCESSOR CONTROL 4 Indoor unit models Outdoor...

Page 4: ...o 120 C or more the compressor is turned OFF After 3 minutes since the compressor has been turned OFF if the temperature of discharge temperature thermistor becomes 100 C or less the compressor is turned ON 4 Outdoor fan speed control MU GD80VB MUH GD80VB Outdoor fan speed control is as follows Outdoor fan speed High or Med Indoor fan speed 20 C 22 C Low 30 C 33 C High Temperature of ambient tempe...

Page 5: ...RATION 35 30 25 20 15 10 10 15 20 25 30 35 Set temperature Initial room temperature Set temperature and initial room temperature in DRY mode Thermostat Indoor fan Outdoor fan Compressor ON 8 minutes 3 minutes ON OFF OFF OFF OFF OFF OFF OFF OFF ON ON ON ON ON ON Operation time chart Example When the room temperature is 23 C or over 4 Coil frost prevention The operation is the same as coil frost pre...

Page 6: ...r prevention control When the compressor is not operating MSC GE20 25 35VB If the temperature of indoor coil thermistor RT12 is 0 C or less the fan stops If the temperature of indoor coil thermistor RT12 is more than 0 C the fan operates at Very Low When the compressor is operating If the temperature of RT12 is 22 C or more the fan operates at set speed If the temperature of RT12 is less than 22 C...

Page 7: ...board with detection by the defrost thermistor 1 Starting conditions of defrost When all conditions of a c are satisfied the defrosting operation starts a Under the heat operation the compressor cumulative operation time exceeds 40 minutes without the defrosting opera tion working b The defrost thermistor reads 3 C or less c After releasing the high pressure protection 4 minutes and 10 seconds hav...

Page 8: ...rrent to the fan motor is shut off 3 minutes later the electric current is applied to the fan motor again During the fan motor lock up the OPERATION INDICATOR lamp flashes ON and OFF to show the fan motor abnormality 1 5 AUTO VANE OPERATION MSC MSH 1 Horizontal vane 1 Cold air prevention in HEAT operation When any of the following conditions occur in HEAT operation the vane angle changes to Angle ...

Page 9: ...of indoor coil thermistor main and indoor coil thermistor sub MS GD80VB MSH GD80VB In swing operation of ECONO COOL operation mode the initial airflow direction is adjusted to Horizontal According to the temperature of indoor coil thermistor Tp 1 at starting of this operation next downward blow time is decided Then when the downward blow has been finished next horizontal blow time is decided For i...

Page 10: ... mode and outer temperature con ditions Approximately 2 to 13 minutes for 11 minutes after compressor has started Opening is set by standard opening Standard opening is set according to each operation mode and outer temperature conditions 13 minutes after compressor has started LEV opening is corrected once every 2 minutes so that discharge temperature becomes the target discharge temperature When...

Page 11: ...th the outdoor fan ON for prevention of it 4 Outdoor temperature detecting control To detect the exact outdoor temperature in this mode the compressor turns OFF but the outdoor fan stays ON for 3 minutes once every 1 hour If the outdoor temperature rises over 19 C the unit goes back to the normal COOL mode If the outside temperature stays below 19 C the unit continues to run in the low outside tem...

Page 12: ... refrigerant circuit as the cooling circuit The compressor and the indoor fan are controlled by the room tem perature By such controls indoor air flow amounts will be reduced in order to lower humidity without much room temperature decrease 35 30 25 20 15 10 10 15 20 25 30 35 Set temperature C Initial room temperature C Set temperature and initial room temperature in dry mode 1 Thermostat control ...

Page 13: ...ol works the fan speed changes as follows to blow out warm air gradually Gradation of fan speed in initial Time condition Indoor fan speed Less than 2 minutes Low 2 to 4 minutes Med More than 4 minutes High or Super high The upper limit of the fan speed in MANUAL is the set speed When the temperature of indoor coil thermistor has been 40 C or more or when the set speed has been changed this contro...

Page 14: ...g conditions When all of the following conditions a d are satisfied defrost heater turns ON to prevent ice from foaming on the base of outdoor unit a HEAT mode is selected b The ambient temperature thermistor reads 5 C or less for 5 minutes continuously NOTE1 c The defrost thermistor reads 1 C or less for 5 minutes continuously d Outdoor fan motor is turned ON 2 Releasing conditions When any of th...

Page 15: ...izontal vane position depend on the selected operation mode when the operation mode changes over they change to the exclusive ones 2 5 OUTDOOR FAN MOTOR CONTROL Fan speed is switched according to the compressor frequency 2 6 AUTO VANE OPERATION 1 Horizontal vane 1 Cold air prevention in HEAT operation When any of the following conditions occur in HEAT operation the vane angle changes to horizontal...

Page 16: ...nditioner repeats the swing operation in various cycle as follows Temperature of indoor coil thermistor C Downward blow time second Horizontal blow time second A 15 or less 2 23 B 15 to 17 5 20 C 17 to 18 8 17 D 18 to 20 11 14 E 20 to 21 14 11 F 21 to 22 17 8 G 22 to 24 20 5 H More than 24 23 2 2 7 DRAIN PUMP FLOAT SENSOR CONTROL MLZ Drain pump motor OFF When ON timer is set or during multi system...

Page 17: ...HC FD25 35 GE POWER SUPPLY NOISE FILTER CIRCUIT RESISTOR SWITCHING POWER TRANSISTOR RELAY SMOOTHING CAPACITOR CURRENT TRANSFORMER COMPRESSOR DIODE MODULE1 DIODE MODULE2 REACTOR P W V U N IPM U W MS 3 V BOOSTER CHOPPER CIRCUIT POWER SUPPLY NOISE FILTER CIRCUIT RESISTOR RELAY SMOOTHING CAPACITOR CURRENT TRANSFORMER COMPRESSOR REACTOR P W V U N IPM PFC U W MS 3 V MUZ FD50 Function of main parts NAME ...

Page 18: ...waveform smooth and IPM converts its DC voltage to imitate AC voltage again in order to drive the compressor motor However it has been difficult to meet IEC harmonic current emission standard by above circuit because harmonic gets gener ated in the input current waveform and power factor gets down The simple partial switching method with PAM which has been adopted this time places and utilizes BOO...

Page 19: ...s not have hall element In short the motor is sensorless However it is necessary to locate the polar direction of rotor in order to drive brushless DC motor efficiently The general detection method of the polar direction for such a DC motor is to locate it from the induced voltage by unenergized stator Therefore it is necessary to have a certain period of time in which the stator is being unenergi...

Page 20: ...the set tem perature Second the target operational frequency is regulated by discharge temperature protection high pressure protection electric current protection overload protection and the maximum minimum frequency 2 Maximum minimum frequency in each operation mode Applied model Operational frequency Hz COOL HEAT DRY Minimum Maximum Minimum Maximum Minimum Maximum MUZ GC25 32 85 28 105 32 41 MUZ...

Page 21: ...ontrol ON condition 1 Pre heat control is turned ON for 15 or 30 min after the breaker is turned ON 2 30 min after the unit is stopped pre heat control is turned ON for 15 or 30 min and turned OFF for 30 min This is repeated as shown in the graph until the breaker is turned OFF When outside temperature is 20 C or below pre heat control is ON for 30 min When outside temperature is 21 C or above pre...

Page 22: ... controller ON LEV is positioned First LEV is full closed at zero pulse and then positioned During 1 to 15 minutes after compressor starts LEV is fixed to standard opening degree according to opera tional frequency of compressor More than about 15 minutes have passed since com pressor start up LEV opening degree is corrected to get target discharge tem perature of compressor For lower discharge te...

Page 23: ... diminishing super heat 3 Control data Reference value of target discharge temperature COOL HEAT C Applied model A B C D E F MUZ GC25 54 36 59 46 65 55 70 63 75 70 79 76 MUZ GC35 51 42 57 50 62 58 67 65 71 70 71 70 MUZ FD25 35 MUZ GE42 49 43 55 51 61 59 67 69 72 75 76 80 MUZ FD50 45 51 58 59 65 65 72 72 72 72 72 72 MUZ GE25 52 43 58 50 65 55 67 59 70 65 71 69 MUZ GE35 53 43 60 51 64 58 67 59 72 69...

Page 24: ...t to change without notice Copyright 2007 MITSUBISHI ELECTRIC CO LTD Distributed in Dec 2008 No OBT17 REVISED EDITION D 6 Distributed in Aug 2008 No OBT17 REVISED EDITION C 5 Distributed in Apr 2008 No OBT17 REVISED EDITION B 7 Distributed in Aug 2007 No OBT17 REVISED EDITION A 7 Distributed in Feb 2007 No OBT17 7 Made in Japan ...

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