Mitsubishi Electric MS-A WA Service Technical Manual

Split-type air conditioners

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Service technical manual (28 pages)

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SPLIT-TYPE AIR CONDITIONERS

SERVICE TECHNICAL GUIDE

Models

MS-A•WA

MSZ-A•NA

MSY-A•NA

MSZ-FD•NA

MSZ-FE•NA

MSZ-D•NA

MSY-D•NA

MSZ-GA•NA

MSY-GA•NA

MSZ-GE•NA

MSY-GE•NA

MFZ-KA•NA

CONFIDENTIAL

(FOR INTERNAL USE ONLY)

Revision H:

• MXZ-3B24NA -

4B36NA -

Please void OBT16 REVISED EDITION-G.

· MU-A•WA

· MUZ-A•NA, -

· MUY-A•NA

· MUZ-FD•NA, -

· MUZ-FE•NA

· MUZ-D•NA, -

· MUY-D•NA

· MUZ-GA•NA, -

· MUY-GA•NA

· MUZ-GE•NA

· MUY-GE•NA

MXZ-A•NA, -

MXZ-B•NA, -

CONTENTS

1. MS MICROPROCESSOR CONTROL ·················· 4

2. MSZ, MSY MICROPROCESSOR CONTROL ······7

3. MXZ MICROPROCESSOR CONTROL ·············· 21

4. MFZ MICROPROCESSOR CONTROL ·············· 35

, MXZ-3B30NA -

and MXZ-

have been added.

No. OBT16

REVISED EDITION-H

, -

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Summary of Contents for Mitsubishi Electric MS-A WA

Page 1 Revision H: • MXZ-3B24NA - , MXZ-3B30NA - and MXZ- 4B36NA - have been added. SPLIT-TYPE AIR CONDITIONERS Please void OBT16 REVISED EDITION-G. No. OBT16 REVISED EDITION-H SERVICE TECHNICAL GUIDE Models MS-A•WA · MU-A•WA MSZ-A•NA · MUZ-A•NA, - MSY-A•NA · MUY-A•NA MSZ-FD•NA ·...
Page 2 Revision A: • MXZ-3A30NA- has been added. Revision B: • MXZ-2A20NA- MXZ-4A36NA, MSZ-FD, MSZ-D and MSY-D have been added. Revision C: • MXZ-2A20NA- has been added. Revision D: • MSZ-GA•NA and MSY-GA•NA have been added. Revision E: • MSZ-FE•NA, MSZ-GE•NA, MSY-GE•NA and MXZ-B•NA have been added. Revision F: •...
Page 3: Table Of Contents
1. MS MICROPROCESSOR CONTROL ··················································································································· 4 Indoor unit models Outdoor unit models MS-A09/12WA MU-A09/12WA 1-1. COOL OPERATION ······································································································································· 4 1-2. DRY OPERATION ·········································································································································· 4 1-3. AUTO VANE OPERATION ····························································································································· 6 2. MSZ, MSY MICROPROCESSOR CONTROL ······································································································· 7 Indoor unit models Outdoor unit models MSZ-A09/12/15/17/24NA MUZ-A09/12/15/17/24NA...
Page 4: Ms Microprocessor Control
MS MICROPROCESSOR CONTROL 1-1. COOL ( ) OPERATION 1. Thermostat control Thermostat turns ON or OFF by the difference between room temperature and set temperature. Room temperature minus Room temperature minus set temperature (Initial) set temperature (During operation) Thermostat -1.8°F(-1°C) or more less than -1.8°F(-1°C) -1.8°F -1.35°F...
Page 5 1. Thermostat control Thermostat turns ON or OFF by the difference between room temperature and set temperature. Room temperature minus Room temperature minus set temperature (Initial) set temperature (During operation) Thermostat -3.6°F(-2°C) or more less than -3.6°F(-2°C) -3.6°F -1.35°F (-2°C) (-0.75°C) 2.
Page 6: Auto Vane Operation
1-3. AUTO VANE OPERATION 1. Horizontal vane ECONO COOL ( ) operation (ECONOmical operation) When ECONO COOL button is pressed in COOL mode, set temperature is automatically set 3.6°F (2°C) higher than that in COOL mode. Also the horizontal vane swings in various cycle according to the temperature of indoor heat exchanger (indoor coil thermistor).
Page 7: Msz, Msy Microprocessor Control
MSZ, MSY MICROPROCESSOR CONTROL 2-1. COOL ( ) OPERATION 1. Thermostat control Thermostat turns ON or OFF by the difference between room temperature and set temperature. Room temperature minus Room temperature minus set temperature (Initial) set temperature (During operation) Thermostat -1.8°F(-1°C) or more less than -1.8°F(-1°C) -1.8°F...
Page 8: Dry Operation
2-2. DRY ( ) OPERATION Set temperature and initial room temperature in dry mode Set temperature is as shown on the right chart. 95(35) The system for dry operation uses the same refrigerant circuit as the cooling circuit. 86(30) The compressor and the indoor fan are controlled by the room tem- perature.
Page 9 (2) Cold air prevention control MSZ-A09/12/15/17 MSZ-FD MSZ-FE MSZ-D MSZ-GE When the compressor is not operating, ( ) if the temperature of room temperature thermistor is less than 66°F (19°C), the fan stops. ( ) if the temperature of room temperature thermistor is 66°F (19°C) or more and ( ) if the temperature of indoor coil thermistor is less than 32°F (0°C), the fan stops.
Page 10: Auto Change Over
(2) Releasing conditions of defrosting Defrosting is released when any one of the following conditions is satisfied: a) The defrost thermistor continues to read "Defrost finish temperature" for 30 seconds. Refer to "CHANGE IN DEFROST SETTING of SERVICE FUNCTIONS in OUTDOOR UNIT SERVICE MANUAL". b) Defrosting time has exceeded 10 minutes.
Page 11: Outdoor Fan Motor Control
(2) Mode change In case of the following conditions, the operation mode is changed. COOL mode changes to HEAT mode when 15 minutes have passed with the room temperature 2 - 4°F (1 - 2°C) below the set temperature. HEAT mode changes to COOL mode when 15 minutes have passed with the room temperature 2 - 4°F (1 - 2°C) above the set temperature.
Page 12: Inverter System Control
<SWING operation> In swing operation of ECONO COOL operation mode, the initial air flow direction is adjusted to “Horizontal”. According to the temperature of indoor coil thermistor RT12 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 initial 10 minutes the swing operation is performed in table G~H for quick cooling.
Page 13 MUZ-A24 MUY-A24 MUZ-D MUY-D MUZ-FE18 MUZ-GA MUY-GA MUZ-GE24 MUY-GE24 CURRENT TRANSFORMER REACTOR NOISE RESISTOR POWER SMOOTHING FILTER SUPPLY CAPACITOR CIRCUIT RELAY POWER FACTOR INTELLIGENT COMPRESSOR CORRECTION POWER MODULE MODULE Function of main parts NAME FUNCTION INTELLIGENT POWER MODULE It supplies 3-phase AC power to compressor. SMOOTHING CAPACITOR It stabilizes the DC voltage and supplies it to INTELLIGENT POWER MODULE.
Page 14 3. Purpose of PAM adoption PAM (Pulse Amplitude Modulation) has been adopted for the efﬁ ciency improvement and the adaptation to IEC harmonic cur- rent emission standard Outline of simple partial switching method In conventional inverter models, DIODE MODULE rectiﬁ es AC voltage to DC voltage, SMOOTHING CAPACITOR makes its DC waveform smooth, and INTELLIGENT POWER MODULE converts its DC voltage to imitated AC voltage again in order to drive the compressor motor.
Page 15 4. Intelligent power module INTELLIGENT POWER MODULE consists of the following components · IGBT (x6): Converts DC waveform to 3-phase AC waveform and outputs it. · Drive Circuit: Drives transistors. · Protection circuit: Protects transistors from overcurrent. Since the above components are all integrated in INTELLIGENT POWER MODULE, INTELLIGENT POWER MODULE has a merit to make the control circuit simplify and miniaturize.
Page 16 2-7-3. Sine wave control In these air conditioners, compressor equips brushless DC motor which does 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 mo- tor efﬁ...
Page 17: Operational Frequency Control Of Outdoor Unit
2-8. OPERATIONAL FREQUENCY CONTROL OF OUTDOOR UNIT 1. Outline The operational frequency is as following: First, the target operational frequency is set based on the difference between the room temperature and the set tempera- ture. Second, the target operational frequency is regulated by discharge temperature protection, high pressure protection, electric current protection and overload protection and also by the maximum/minimum frequency.
Page 18: Expansion Valve Control (Lev Control)
2-9. EXPANSION VALVE CONTROL (LEV CONTROL) (1) Outline of LEV control The LEV basic control is comprised of setting LEV opening degree to the standard opening degrees set for each opera- tional frequency of the compressor. However, when any change in indoor/outdoor temperatures or other factors cause air conditioning load fluctuation, the LEV control also works to correct LEV opening degree based on discharge tempera- ture (Shell temperature) of the compressor, developing the unit's performance.
Page 19 (3) Control data (MUZ-FE18 MUZ-GE24 MUY-GE24) (Hz) (Other models) (Hz) Operational frequency of the compressor (a) Reference value of target discharge temperature COOL / HEAT (MUZ) °F/°C Applied model COOL 122/50 127/53 140/60 151/66 158/70 158/70 MUZ-A09/12 HEAT 113/45 126/52 138/59 154/68 169/76 169/76 COOL 129/54 136/58 147/64 158/70 158/70 158/70 MUZ-A15/17 MUY-A15/17 HEAT 120/49 136/58 151/66 165/74 180/82 185/85...
Page 20: Pre-Heat Control
2-10. PRE-HEAT CONTROL MUZ-FD MUZ-FE MUZ-GE 1. Outline Compressor is energized to improve the start-up of compressor at a low outside temperature even when compressor is stopped. 2. Pre-heat control Compressor Pre-heat control 68°F Outside temperature (20°C) 30 minutes 1 hour Pre-heat control ON condition (1) Compressor is not operating.
Page 21: Mxz Microprocessor Control
MXZ MICROPROCESSOR CONTROL 3-1. INVERTER SYSTEM CONTROL 3-1-1. Inverter main power supply circuit CURRENT TRANSFORMER REACTOR NOISE RESISTOR POWER SMOOTHING FILTER SUPPLY CAPACITOR CIRCUIT RELAY POWER FACTOR INTELLIGENT COMPRESSOR CORRECTION POWER MODULE MODULE Function of main parts NAME FUNCTION INTELLIGENT POWER MODULE It supplies 3-phase AC power to compressor.
Page 22 3. Power factor improvement Booster coil reactor and POWER FACTOR CORRECTION MODULE rectify AC to DC and control its voltage. In the motor drive system of sine wave control, power factor can be improved by reducing harmonics. POWER FACTOR CORRECTION MODULE and reactor stabilize the voltage of DC supplied to inverter circuit and make its waveform smooth. 4.
Page 23: Expansion Valve Control (Lev Control)
3-2. EXPANSION VALVE CONTROL (LEV CONTROL) Linear expansion valve (LEV) is controlled by “Thermostat ON” commands given from each unit. Indoor unit status LEV opening Stop of all indoor unit Opening before stop → 500 pulses in 15 minutes When outdoor unit is operating, COOL: 5 pulses (full closed) some indoor units stop and some HEAT: (MXZ-2A/3A30NA/2B): 140 pulses (slightly opened)
Page 24 MXZ-2A20NA/3A30NA The table below shows the role of Exclusive LEV and Receiver LEV in each operation mode. Discharge Evaporation Circulation Amount High Pressure Capacity Distribution Temperature Temperature Control Protection Protection Protection ○ ○ ○ ○ ○ Exclusive LEV COOL × ×...
Page 25 Determination of LEV standard opening in each indoor unit • The standard opening is on the straight line, which connects an each standard point in the section where divided into seven according to the operation frequency of compressor as shown in the figure below. (LEV opening is controlled in proportion to the operation frequency.) NOTE: Opening is adjusted at the standard opening according to the indoor unit conditions.
Page 26 MXZ-2A20NA- MXZ-2B20NA MXZ-2B20NA- Exclusive LEV Standard opening (pulse) LEV Opening (code) COOL 120 130 136 146 156 160 170 180 190 200 HEAT 248 248 258 266 274 280 286 292 300 306 Difference in capacity Difference in operation number Code3,4 Code5,6 Code7,8 Code9,10 Code11,12 Code13,14 Code15or above COOL HEAT...
Page 27 <Correction> COOL HEAT Discharge temperature ● ● ● Each correction • (Each gas pipe temperature thermistor - Minimum gas pipe temperature thermistor) 1 ● ● — • (Main indoor coil thermistor - Sub indoor coil thermistor) 1 Perform this, when number of operation units is 2 units or more. (MXZ-2A20NA and MXZ-3A30NA only) 2 Correct the LEV opening by discharge temperature.
Page 28 MXZ-3A30NA- MXZ-4A36NA MXZ-3B24NA MXZ-3B30NA MXZ-4B36NA Target discharge temperature (°F/°C) COOL HEAT Operation frequency Number of operating unit of compressor (Hz) 4 units 4 units 1 unit 2 units 3 units 1 unit 2 unit 3 units (MXZ-4A/4B) (MXZ-4A/4B) Minimum ~ 14 95/35 131/55 134.6/57...
Page 29: Operational Frequency Range
b) Correct the LEV separately by temperature difference “ ∆RT” between main/sub indoor coil thermistor. LEV opening ∆RT (°F/°C) correction (pulse) 10.8/6 ∆RT 7.2/4 ∆RT < 10.8/6 ∆RT < 7.2/4 In addition, decrease the target discharge temperature corresponding ∆RT. Temperature to be ∆...
Page 30 MXZ-2B20NA COOL (Hz) HEAT (Hz) Number of operating Capacity code DRY (Hz) unit Min. Max. Min. Max. Defrost 3, 4 9, 10 2 ~ 7 8 ~ 10 11 ~ 13 14 ~ 16 17 ~ MXZ-2B20NA- COOL (Hz) HEAT (Hz) Number of operating Capacity code DRY (Hz)
Page 31: Heat Defrosting Control
MXZ-3B24NA MXZ-3B30NA MXZ-4B36NA COOL (Hz) HEAT (Hz) Number of operating Capacity code DRY (Hz) unit Min. Max. Min. Max. Defrost 9,10 5 ~ 7 8 ~ 10 11 ~ 13 14 ~ 16 17 ~ 3 (MXZ- 3B) 3 (MXZ-4B) 4 (MXZ-4B) 12 ~ 3-4.
Page 32: Outdoor Fan Control
3-6. OUTDOOR FAN CONTROL Fan speed is switched according to the number of operating indoor unit and the compressor frequency. MXZ-2B20NA <Relation between compressor frequency and fan speed> Compressor frequency (Hz) Fan speed Down Down High MXZ-2B20NA Min. Compressor frequency Max.
Page 33: Pre-Heat Control
3-7. PRE-HEAT CONTROL MXZ-2A20NA- MXZ-3A30NA- MXZ-4A36NA MXZ-2B20NA MXZ-2B20NA- MXZ-3B24NA MXZ-3B30NA MXZ-4B36NA The compressor is energized even while it is not operating. This is to generate heat at the winding to improve the compressor's start-up condition. Power Compressor Defrost thermistor 69.8°F (21°C) 30 minutes 30 minutes...
Page 34: Dry Operation
3-9. DRY OPERATION 1. Thermostat control Thermostat turns ON or OFF by the difference between room temperature and set temperature. Room temperature minus Room temperature minus set temperature (Initial) set temperature (During operation) Thermostat -3.6°F(-2°C) or more less than -3.6°F(-2°C) -3.6°F -1.35°F (-2°C)
Page 35: Mfz Microprocessor Control
MFZ MICROPROCESSOR CONTROL 4-1. COOL ( ) OPERATION 1. Thermostat control Refer to MXZ MICROPROCESSOR CONTROL, COOL OPERATION (3-8.1.). 2. Indoor fan speed control Indoor fan operates continuously at the set speed by FAN SPEED CONTROL button regardless of the thermostat's OFF- ON.
Page 36: Heat Operation
4-3. HEAT ( ) OPERATION 1. Thermostat control Refer to MXZ MICROPROCESSOR CONTROL, HEAT OPERATION (3-10.1.). 2. Indoor fan speed control (1) Indoor fan operates at the set speed by FAN SPEED CONTROL button. In Auto the fan speed is as follows. Set temperature minus room Set temperature minus Fan speed...
Page 37: Auto Change Over
4-4. AUTO CHANGE OVER ··· AUTO MODE OPERATION Once desired temperature is set, unit operation is switched automatically between COOL and HEAT operation. 1. Mode selection (1) Initial mode At first, indoor unit operates only indoor fan with outdoor unit OFF for 3 minutes to detect present room temperature. Following the conditions below, operation mode is selected.
Page 38: Auto Vane Operation
4-6. AUTO VANE OPERATION Horizontal vane (1) Cold air prevention in HEAT operation When any of the following conditions occurs in HEAT operation, the vane angle changes to Vertical position automati- cally to prevent cold air blowing on users. Compressor is not operating. Defrosting is performed.
Page 40 HEAD OFFICE: TOKYO BLDG.,2-7-3, MARUNOUCHI, CHIYODA-KU, TOKYO 100-8310, JAPAN © Copyright 2006 MITSUBISHI ELECTRIC CO.,LTD Distributed in Jan. 2011. No. OBT16 REVISED EDITION-H Distributed in Sep. 2010. No. OBT16 REVISED EDITION-G 6 Distributed in Mar. 2010. No. OBT16 REVISED EDITION-F 6 Distributed in Sep.

Mitsubishi Electric MS-A WA Service Technical Manual

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