Mitsubishi Electric MUZ-LN35VGHZ2-E1 Service Manual

Outdoor unit

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OUTDOOR UNIT

SERVICE MANUAL

Models

MUZ-LN25VGHZ

MUZ-LN35VGHZ

MUZ-LN50VGHZ

MUZ-LN25VGHZ2

MUZ-LN35VGHZ2

MUZ-LN50VGHZ2

MUZ-LN25VGHZ

MUZ-LN35VGHZ

Revision G:

• MUZ-LN25/35VGHZ2-

MUZ-LN50VGHZ2-

been added.

OBH768 REVISED EDITION-F is void.

HFC

utilized

R32

ER1

ET1

ER1

ET1

ER1

ET1

ER1

SC1

ER1

Indoor unit service manual

MSZ-LN•VGW/V/B/R Series (OBH766)

CONTENTS

1. TECHNICAL CHANGES ······························3

2. SERVICING PRECAUTIONS FOR UNITS

USING REFRIGERANT R32 ·························4

3. PART NAMES AND FUNCTIONS ··················6

4. SPECIFICATION ········································7

5. NOISE CRITERIA CURVES ························ 10

6. OUTLINES AND DIMENSIONS ··················· 12

7. WIRING DIAGRAM ··································· 15

8. REFRIGERANT SYSTEM DIAGRAM ··········· 21

9. PERFORMANCE CURVES ························ 24

10. ACTUATOR CONTROL ····························· 43

11. SERVICE FUNCTIONS ······························ 44

12. TROUBLESHOOTING ······························· 45

13. DISASSEMBLY INSTRUCTIONS ················· 69

PARTS CATALOG (OBB768)

SC1

ER1

No. OBH768

REVISED EDITION-G

SC1

ER2

SC1

ER2

and

ER2

have

Table of Contents

Summary of Contents for Mitsubishi Electric MUZ-LN35VGHZ2-E1

Page 1: Table Of Contents
Revision G: • MUZ-LN25/35VGHZ2- MUZ-LN50VGHZ2- have been added. OBH768 REVISED EDITION-F is void. OUTDOOR UNIT No. OBH768 SERVICE MANUAL REVISED EDITION-G utilized Models MUZ-LN25VGHZ MUZ-LN35VGHZ MUZ-LN50VGHZ MUZ-LN25VGHZ2 MUZ-LN35VGHZ2 MUZ-LN50VGHZ2 Indoor unit service manual MSZ-LN•VGW/V/B/R Series (OBH766) CONTENTS 1. TECHNICAL CHANGES ······························3 2.
Page 2 Use the specified 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.
Page 3: Technical Changes
TECHNICAL CHANGES MUZ-LN25VGHZ - MUZ-LN35VGHZ - MUZ-LN50VGHZ - 1. New model MUZ-LN25VGHZ - MUZ-LN25VGHZ2 - MUZ-LN35VGHZ - MUZ-LN35VGHZ2 - 1. The heat exchanger has been changed. 2. The refrigerant amount has been changed. MUZ-LN25VGHZ2 - MUZ-LN25VGHZ2 - MUZ-LN35VGHZ2 - MUZ-LN35VGHZ2 - 1.
Page 4: Servicing Precautions For Units Using Refrigerant R32
SERVICING PRECAUTIONS FOR UNITS USING REFRIGERANT R32 Servicing precautions for units using refrigerant R32 WARNING This unit uses a flammable refrigerant. If refrigerant leaks and comes in contact with fire or heating part, it will create harmful gas and there is risk of fire. Do not use means to accelerate the defrosting process or to clean, other than those recommended by the manufacturer.
Page 5 5. Detection of Flammable Refrigerants Under no circumstances shall potential sources of ignition be used in the searching for or detection of refrigerant leaks. A halide torch (or any other detector using a naked flame) shall not be used. 6. Leak Detection Methods Electronic leak detectors may be used to detect refrigerant leaks but, in the case of flammable refrigerants, the sensitivity may not be adequate, or may need re-calibration.
Page 6: Part Names And Functions
PART NAMES AND FUNCTIONS MUZ-LN25VGHZ MUZ-LN25VGHZ2 MUZ-LN35VGHZ MUZ-LN35VGHZ2 Air inlet (Back and side) Piping Air outlet Drain hose Drain outlet MUZ-LN50VGHZ Air inlet (Back and side) Piping Drain hose Air outlet Drain outlet MUZ-LN50VGHZ2 Air inlet (Back and side) Piping Air outlet Drain hose Drain outlet...
Page 7: Specification
SPECIFICATION MUZ- MUZ- MUZ- MUZ- Outdoor model LN25VGHZ LN25VGHZ2 LN35VGHZ LN35VGHZ2 Power supply Single phase, 230 V, 50 Hz Cooling 2.5 (0.8 - 3.5) 2.5 (0.8 - 3.5) 3.5 (0.8 - 4.0) 3.5 (0.8 - 4.0) Capacity Rated (Min.-Max.) Heating 3.2 (1.0 - 6.3) 3.2 (0.8 - 6.3) 4.0 (1.0 - 6.6)
Page 8 Outdoor model MUZ-LN50VGHZ MUZ-LN50VGHZ2 Single phase, 230 V, 50 Single phase, 230 V, 50 Power supply Cooling 5.0 (1.4 - 5.8) 5.0 (1.4 - 5.8) Capacity Rated (Min. - Max.) Heating 6.0 (1.8 - 8.7) 6.0 (1.8 - 8.7) Breaker Capacity Cooling 1,380 1,380...
Page 9 Specifications and rated conditions of main electric parts Model MUZ-LN25VGHZ MUZ-LN25VGHZ2 MUZ-LN35VGHZ MUZ-LN35VGHZ2 Item (C62, C63) 600 µF/ 620 µF 420 V Smoothing capacitor (C61, C62)(- (C61, C62, C63) 600 µF/ 620 µF 420 V 15 A 600 V 15 A 600 V (DB61) 15 A 600 V 15 A 600 V...
Page 10: Noise Criteria Curves
NOISE CRITERIA CURVES MUZ-LN25VGHZ2 MUZ-LN25VGHZ FUNCTION SPL(dB(A)) LINE FUNCTION SPL(dB(A)) LINE COOLING COOLING HEATING HEATING NC-70 NC-70 NC-60 NC-60 NC-50 NC-50 NC-40 NC-40 NC-30 NC-30 NC-20 NC-20 NC-10 NC-10 1000 2000 4000 8000 1000 2000 4000 8000 BAND CENTER FREQUENCIES, Hz BAND CENTER FREQUENCIES, Hz MUZ-LN35VGHZ2 MUZ-LN35VGHZ...
Page 11 MUZ-LN50VGHZ MUZ-LN50VGHZ2 FUNCTION SPL(dB(A)) LINE FUNCTION SPL(dB(A)) LINE COOLING COOLING HEATING HEATING NC-70 NC-70 NC-60 NC-60 NC-50 NC-50 NC-40 NC-40 NC-30 NC-30 NC-20 NC-20 NC-10 NC-10 1000 2000 4000 8000 1000 2000 4000 8000 BAND CENTER FREQUENCIES, Hz BAND CENTER FREQUENCIES, Hz Test conditions Cooling: Dry-bulb temperature 35°C Heating: Dry-bulb temperature 7°C Wet-bulb temperature 6°C...
Page 12: Outlines And Dimensions
OUTLINES AND DIMENSIONS MUZ-LN25VGHZ MUZ-LN35VGHZ Unit: mm MUZ-LN25VGHZ2 MUZ-LN35VGHZ2 OBH768G...
Page 13 MUZ-LN50VGHZ Unit: mm REQUIRED SPACE *1. 500 mm or more when front and sides of the unit are clear 417.5 Air in Air in Air out 2-holes 10 21 *2. When any 2 sides of left, right and rear of the unit are clear Service panel Liquid refrigerant pipe joint Refrigerant pipe (flared)
Page 14 MUZ-LN50VGHZ2 REQUIRED SPACE FLARED ø6.35 (1/4”) FLARED ø9.52 (3/8”) OBH768G...
Page 15: Wiring Diagram
WIRING DIAGRAM MUZ-LN25VGHZ MUZ-LN25VGHZ2- OBH768G...
Page 16 MUZ-LN25VGHZ2- OBH768G...
Page 17 MUZ-LN35VGHZ MUZ-LN35VGHZ2- OBH768G...
Page 18 MUZ-LN35VGHZ2- OBH768G...
Page 19 MUZ-LN50VGHZ- MUZ-LN50VGHZ- OBH768G...
Page 20 MUZ-LN50VGHZ2- OBH768G...
Page 21: Refrigerant System Diagram
REFRIGERANT SYSTEM DIAGRAM Unit: mm MUZ-LN25VGHZ MUZ-LN35VGHZ MUZ-LN25VGHZ2 MUZ-LN35VGHZ2 Refrigerant pipe ø9.52 4-way valve (with heat insulator) Muffler Outdoor heat exchanger Stop valve temperature thermistor Outdoor Muffler RT68 Discharge heat Flared connection exchanger temperature thermistor RT62 Ambient Compressor temperature thermistor RT65 Defrost thermistor...
Page 22 MUZ-LN50VGHZ2 Refrigerant pipe ø9.52 (with heat insulator) 4-way valve Stop valve Outdoor Flared connection Discharge heat Ambient temperature exchanger temperature thermistor Defrost thermistor RT62 thermistor RT65 RT61 Compressor Outdoor heat exchanger temperature thermistor Flared connection RT68 Strainer Capillary tube Strainer ø4.0×ø2.4×100 #100 #100...
Page 23 MAX. REFRIGERANT PIPING LENGTH and MAX. HEIGHT DIFFERENCE Refrigerant piping: m Piping size O.D: mm Model Max. Height difference B Max. Length A Liquid MUZ-LN25VGHZ MUZ-LN35VGHZ 9.52 6.35 MUZ-LN25VGHZ2 MUZ-LN35VGHZ2 MUZ-LN50VGHZ 9.52 6.35 MUZ-LN50VGHZ2 Indoor unit Max. Height difference Max. Length Outdoor unit ADDITIONAL REFRIGERANT CHARGE (R32: g) Refrigerant piping length (one way) Outdoor unit...
Page 24: Performance Curves
PERFORMANCE CURVES MUZ-LN25VGHZ MUZ-LN35VGHZ MUZ-LN50VGHZ MUZ-LN25VGHZ2 MUZ-LN35VGHZ2 MUZ-LN50VGHZ2 The standard specifications apply only to the operation of the air conditioner under normal conditions. Since operating condi- tions vary according to the areas where these units are installed, the following information has been provided to clarify the operating characteristics of the air conditioner under the conditions indicated by the performance curve.
Page 25 9-1. CAPACITY AND INPUT CURVES Cooling capacity (at Rated frequency) 10.4 10.1 Indoor intake air Wet-bulb temperature( ) Outdoor intake air Dry-bulb temperature(°C) Total input (Cooling : at Rated frequency Indoor intake air Wet-bulb temperature( ) Outdoor intake air Dry-bulb temperature (°C) Heating capacity (at Rated frequency) 19.1...
Page 26 9-2. CAPACITY AND INPUT CORRECTION BY OPERATIONAL FREQUENCY OF COMPRESSOR MUZ-LN25VGHZ Correction of Cooling input Correction of Heating capacity Correction of Heating input Correction of Cooling capacity The operational frequency The operational frequency The operational frequency The operational frequency of compressor (Hz) of compressor (Hz) of compressor (Hz) of compressor (Hz)
Page 27 MUZ-LN50VGHZ Correction of Cooling input Correction of Heating capacity Correction of Heating input Correction of Cooling capacity The operational frequency The operational frequency The operational frequency The operational frequency of compressor (Hz) of compressor (Hz) of compressor (Hz) of compressor (Hz) MUZ-LN50VGHZ2 Correction of Heating capacity Correction of Heating input...
Page 28 9-4. OUTDOOR LOW PRESSURE AND OUTDOOR UNIT CURRENT COOL operation Dry-bulb temperature (°C) Relative humidity (%) Both indoor and outdoor unit are under the same temperature/ humidity condition. Operation: Test run operation (Refer to 9-3.) Outdoor low pressure MUZ-LN25VGHZ MUZ-LN25VGHZ2 (kgf/cm [Gauge])(MPa [Gauge]) (kgf/cm...
Page 29 Outdoor unit current MUZ-LN25VGHZ MUZ-LN25VGHZ2 MUZ-LN35VGHZ MUZ-LN35VGHZ2 Ambient temperature(°C) Ambient temperature(°C) Ambient temperature(°C) Ambient temperature(°C) Ambient humidity(%) Ambient humidity(%) Ambient humidity(%) Ambient humidity(%) MUZ-LN50VGHZ MUZ-LN50VGHZ2 Ambient temperature(°C) Ambient temperature(°C) Ambient humidity(%) Ambient humidity(%) HEAT operation Condition: Indoor Outdoor Dry bulb temperature (°C) 20.0 20.0 Wet bulb temperature (°C) 14.5...
Page 30 t Rated frequency PERFORMANCE DATA COOL operation a MUZ-LN25VGHZ CAPACITY: 2.5 kW SHF: 0.97 INPUT: 485 W OUTDOOR DB (°C) INDOOR INDOOR DB (°C) WB (°C) INPUT INPUT INPUT INPUT 2.94 2.32 0.79 2.81 2.22 0.79 2.70 2.13 0.79 2.60 2.05 0.79 3.06...
Page 31 t Rated frequency PERFORMANCE DATA COOL operation a MUZ-LN25VGHZ CAPACITY: 2.5 kW SHF: 0.97 INPUT: 485 W OUTDOOR DB (°C) INDOOR INDOOR DB (°C) WB (°C) INPUT INPUT INPUT 2.45 1.94 0.79 2.25 1.78 0.79 2.08 1.64 0.79 2.58 1.73 0.67 2.40 1.61...
Page 32 t Rated frequency PERFORMANCE DATA COOL operation a MUZ-LN25VGHZ2 CAPACITY: 2.5 kW SHF: 0.97 INPUT: 485 W OUTDOOR DB (°C) INDOOR INDOOR DB (°C) WB (°C) INPUT INPUT INPUT INPUT 2.94 2.32 0.79 2.81 2.22 0.79 2.70 2.13 0.79 2.60 2.05 0.79 3.06...
Page 33 t Rated frequency PERFORMANCE DATA COOL operation a MUZ-LN25VGHZ2 CAPACITY: 2.5 kW SHF: 0.97 INPUT: 485 W OUTDOOR DB (°C) INDOOR INDOOR DB (°C) WB (°C) INPUT INPUT INPUT 2.45 1.94 0.79 2.25 1.78 0.79 2.08 1.64 0.79 2.58 1.73 0.67 2.40 1.61...
Page 34 t Rated frequency PERFORMANCE DATA COOL operation a MUZ-LN35VGHZ CAPACITY: 3.5 kW SHF: 0.90 INPUT: 820 W OUTDOOR DB (°C) INDOOR INDOOR DB (°C) WB (°C) INPUT INPUT INPUT INPUT 4.11 2.96 0.72 3.94 2.84 0.72 3.78 2.72 0.72 3.64 2.62 0.72 4.29...
Page 35 t Rated frequency PERFORMANCE DATA COOL operation a MUZ-LN35VGHZ CAPACITY: 3.5 kW SHF: 0.90 INPUT: 820 W OUTDOOR DB (°C) INDOOR INDOOR DB (°C) WB (°C) INPUT INPUT INPUT 3.43 2.47 0.72 3.15 2.27 0.72 2.91 2.09 0.72 3.61 2.16 0.60 3.36 2.02...
Page 36 t Rated frequency PERFORMANCE DATA COOL operation a MUZ-LN35VGHZ2 CAPACITY: 3.5 kW SHF: 0.90 INPUT: 820 W OUTDOOR DB (°C) INDOOR INDOOR DB (°C) WB (°C) INPUT INPUT INPUT INPUT 4.11 2.96 0.72 3.94 2.84 0.72 3.78 2.72 0.72 3.64 2.62 0.72 4.29...
Page 37 t Rated frequency PERFORMANCE DATA COOL operation a MUZ-LN35VGHZ2 CAPACITY: 3.5 kW SHF: 0.90 INPUT: 820 W OUTDOOR DB (°C) INDOOR INDOOR DB (°C) WB (°C) INPUT INPUT INPUT 3.43 2.47 0.72 3.15 2.27 0.72 2.91 2.09 0.72 3.61 2.16 0.60 3.36 2.02...
Page 38 t Rated frequency PERFORMANCE DATA COOL operation a MUZ-LN50VGHZ CAPACITY: 5.0 kW SHF: 0.77 INPUT: 1380 W OUTDOOR DB (°C) INDOOR INDOOR DB (°C) WB (°C) INPUT INPUT INPUT INPUT 5.88 3.47 0.59 1104 5.63 3.32 0.59 1159 5.40 3.19 0.59 1214 5.20...
Page 39 t Rated frequency PERFORMANCE DATA COOL operation a MUZ-LN50VGHZ CAPACITY: 5.0 kW SHF: 0.77 INPUT: 1380 W OUTDOOR DB (°C) INDOOR INDOOR DB (°C) WB (°C) INPUT INPUT INPUT 4.90 2.89 0.59 1352 4.50 2.66 0.59 1435 4.15 2.45 0.59 1490 5.15 2.42...
Page 40 t Rated frequency PERFORMANCE DATA COOL operation a MUZ-LN50VGHZ2 CAPACITY: 5.0 kW SHF: 0.77 INPUT: 1380 W OUTDOOR DB (°C) INDOOR INDOOR DB (°C) WB (°C) INPUT INPUT INPUT INPUT 5.88 3.47 0.59 1104 5.63 3.32 0.59 1159 5.40 3.19 0.59 1214 5.20...
Page 41 t Rated frequency PERFORMANCE DATA COOL operation a MUZ-LN50VGHZ2 CAPACITY: 5.0 kW SHF: 0.77 INPUT: 1380 W OUTDOOR DB (°C) INDOOR INDOOR DB (°C) WB (°C) INPUT INPUT INPUT 4.90 2.89 0.59 1352 4.50 2.66 0.59 1435 4.15 2.45 0.59 1490 5.15 2.42...
Page 42 PERFORMANCE DATA HEAT operation at Rated frequency MUZ-LN25VGHZ CAPACITY: 3.2 kW INPUT: 580 W OUTDOOR WB (°C) INDOOR DB (°C) Q INPUT Q INPUT Q INPUT Q INPUT Q INPUT Q INPUT Q INPUT Q INPUT Q INPUT Q INPUT 0.80 1.22 1.60...
Page 43: Actuator Control
ACTUATOR CONTROL MUZ-LN25VGHZ MUZ-LN35VGHZ MUZ-LN50VGHZ MUZ-LN25VGHZ2 MUZ-LN35VGHZ2 MUZ-LN50VGHZ2 10-1. OUTDOOR FAN MOTOR CONTROL The fan motor turns ON/OFF, interlocking with the compressor. [ON] The fan motor turns ON 5 seconds before the compressor starts up. [OFF] The fan motor turns OFF 15 seconds after the compressor has stopped running. 5 seconds 15 seconds Compressor...
Page 44: Service Functions
SERVICE FUNCTIONS MUZ-LN25VGHZ MUZ-LN35VGHZ MUZ-LN50VGHZ MUZ-LN25VGHZ2 MUZ-LN35VGHZ2 MUZ-LN50VGHZ2 11-1. CHANGE IN DEFROST SETTING Changing defrost finish temperature <JS> To change the defrost finish temperature, cut/solder the JS wire of the outdoor inverter P.C. board. (Refer to 12-6.1) Defrost finish temperature (°C) Jumper wire MUZ-LN25/35VGHZ MUZ-LN50VGHZ...
Page 45: Troubleshooting
TROUBLESHOOTING MUZ-LN25VGHZ MUZ-LN35VGHZ MUZ-LN50VGHZ MUZ-LN25VGHZ2 MUZ-LN35VGHZ2 MUZ-LN50VGHZ2 12-1. CAUTIONS ON TROUBLESHOOTING 1. Before troubleshooting, check the following 1) Check the power supply voltage. 2) Check the indoor/outdoor connecting wire for miswiring. 2. Take care of the following during servicing 1) Before servicing the air conditioner, be sure to turn OFF the main unit first with the remote controller, and then after confirming the horizontal vane is closed, turn OFF the breaker and/or disconnect the power plug.
Page 46 12-2. FAILURE MODE RECALL FUNCTION Outline of the function This air conditioner can memorize the abnormal condition which has occurred once. Even though LED indication listed on the troubleshooting check table (12-3.) disappears, the memorized failure details can be recalled. MSZ-LN25/35VG 1.
Page 47 2. Flow chart of the detailed outdoor unit failure mode recall function Operational procedure The outdoor unit might be abnormal. Check if outdoor unit is abnormal according to the following procedures. Make sure that the remote controller is set to the failure mode recall function. 1.
Page 48 NOTE: Blinking patterns of this mode differ from the ones of 3. Table of outdoor unit failure mode recall function TROUBLESHOOTING CHECK TABLE (12-3.). Indoor/outdoor Outdoor unit POWER lamp Abnormal point LED indication unit failure Condition Remedy failure mode (Indoor unit) (Failure mode/protection) (Outdoor P.C. board) mode recall recall function function None (Normal) —...
Page 49 NOTE: Blinking patterns of this mode differ from the ones of TROUBLESHOOTING CHECK TABLE (12-3.). Indoor/outdoor Outdoor unit POWER lamp Abnormal point LED indication unit failure Condition Remedy failure mode (Indoor unit) (Failure mode/protection) (Outdoor P.C. board) mode recall recall function function 10-time blink Discharge temperature Temperature of discharge temperature • Refer to 12-5. "Check ○...
Page 50 12-3. TROUBLESHOOTING CHECK TABLE Abnormal point/ Con- Symptom LED indication Condition Remedy dition Outdoor unit 1-time blink every Outdoor power sys- Overcurrent protection cut-out operates 3 consecutive times • Reconnect connector of compres- does not op- 2.5 seconds within 1 minute after the compressor gets started. sor.
Page 51 Abnormal point/ Con- Symptom LED indication Condition Remedy dition Outdoor unit MUZ-LN25/35 Outside temperature When the outside temperature thermistor shorts or opens, • Refer to 12-5. Check of outdoor operates. thermistor protec- protective operation without that thermistor is performed. thermistors. 5-time blink tion 2.5 seconds OFF...
Page 52 12-4. TROUBLESHOOTING CRITERION OF MAIN PARTS MUZ-LN25VGHZ MUZ-LN35VGHZ MUZ-LN50VGHZ MUZ-LN25VGHZ2 MUZ-LN35VGHZ2 MUZ-LN50VGHZ2 Part name Check method and criterion Figure Defrost thermistor (RT61) Measure the resistance with a multimeter. Refer to 12-6. “Test point diagram and voltage”, 1. “Inverter P.C. Fin temperature board”, for the chart of thermistor.
Page 53 12-5. TROUBLESHOOTING FLOW A How to check inverter/compressor Disconnect the connector between the compressor and the power module (IC700). Check the voltage between terminals. See 12-5. “Check of open phase”. Replace the inverter P.C. board. Are the voltages balanced? Check the compressor. See 12-5.
Page 54 D Check of compressor winding ● Disconnect the connector between the compressor and the power module (IC700), and measure the resistance between the compressor terminals. <<Measurement point>> At 3 points BLK-WHT * Measure the resistance between the lead wires at 3 points. BLK-RED WHT-RED <<Judgement>> Refer to 12-4. 0 [Ω] ················Abnormal [short] Infinite [Ω] ·······Abnormal [open] NOTE: Be sure to zero the ohmmeter before measurement.
Page 55 G Check of outdoor thermistors Disconnect the connector of thermistor in the inverter P.C. board (see below table), and measure the resistance of thermistor. Replace the thermistor except RT64. Is the resistance of thermistor normal? When RT64 is abnormal, replace the inverter P.C. (Refer to 12-6.1.) board.
Page 56 H Check of R.V. coil MUZ-LN25/35VGHZ MUZ-LN25/35VGHZ2 * First of all, measure the resistance of R.V. coil to check if the coil is defective. Refer to 12-4. * In case CN721 is disconnected or R.V. coil is open, voltage is generated between the terminal pins of the connector although no signal is being transmitted to R.V.
Page 57 I Check of outdoor fan motor Disconnect the connectors CN931 and CN932 from the inverter P.C. board. Check the connection between the connector CN931 and CN932. Is the resistance between each ter- minal of outdoor fan motor normal? (Refer to 12-4.) Disconnect CN932 from the inverter P.C.
Page 58 J Check of power supply Disconnect the connector between the compressor and the power module (IC700). Turn ON power supply and Rectify indoor/outdoor press the emergency operation switch. connecting wire. Is there voltage 230 V AC Replace the indoor Does POWER lamp on the indoor between the indoor terminal electronic control P.C.
Page 59 MSZ-LN25/35VG K Check of LEV (Expansion valve) MSZ-LN50/60VG Turn ON the power supply. <Preparation of the remote controller> While pressing both Operation select button and TEMP button on the remote controller at the same time, press RESET button. First, release RESET button. Hold down the other 2 buttons for another 3 seconds.
Page 60 L Check of inverter P.C. board Check the outdoor fan motor. (Refer to 12-5. .) Is the fuse (F901) blown on the in- verter P.C. board? Check the connection of the connectors (CN931, CN932) of the outdoor fan motor. If the connection is poor, make it correct. Operate the outdoor unit by starting EMERGENCY OPERATION.
Page 61 M How to check miswiring and serial signal error Turn the power supply OFF. Is there rated voltage in the power supply? Check the power supply. Check for incorrect indoor-outdoor connecting wiring. Was the indoor unit ever connected to the Multi (MXZ) series and operated (turned on)? The connection information to the Multi series is stored in the indoor unit.
Page 62 N Check of compressor protector Disconnect the connector of compressor protector in the inverter P.C. board, and check the conduction of compressor protector. Operate the unit and Is the discharge temperature Is the compressor re-confirm if the thermistor normal? Refer to 12-5. protector conductive? “Check of outdoor thermistors”.
Page 63 O Electromagnetic noise enters into TV sets or radios Is the unit earthed? Earth the unit. Is the distance between the antennas Extend the distance between the antennas and and the indoor unit within 3 m, or is the the indoor unit, and/or the antennas and the distance between the antennas and the outdoor unit.
Page 64 12-6. TEST POINT DIAGRAM AND VOLTAGE 1. Inverter P.C. board MUZ-LN25VGHZ MUZ-LN35VGHZ Smoothing Smoothing Smoothing R.V. coil capacitor capacitor capacitor (CN721) Back side of unit DB61 (C63) (C62) 230 V AC (C61) 260 - 370 V DC Fuse (F701) (LN35VGHZ) T3.15AL250V 230 V AC Fuse (F801)
Page 65 MUZ-LN25VGHZ2- MUZ-LN35VGHZ2- R.V.coil Smoothing Smoothing Smoothing Back side of unit (CN721) DB61 capacitor capacitor capacitor (C61) 230 V AC 260 - 370 V DC (C63) (C62) (LN35VGHZ2) 230 V AC Fuse (F901) Fuse (F801) Fuse (F701) T3.15AL250V T3.15AL250V T3.15AL250V Fuse (F61) Fuse (F62) 25 A 250V 15 A 250 V...
Page 66 MUZ-LN25VGHZ2- MUZ-LN35VGHZ2- Smoothing Smoothing Smoothing R.V. coil capacitor capacitor capacitor (CN721) Back side of unit DB61 (C61) (C62) 230 V AC (C63) 260 - 370 V DC Fuse (F701) (LN35VGHZ2) T3.15AL250V 230 V AC Fuse (F801) T3.15AL250V Fuse (F62) T3.15AL250V Output to drive compressor...
Page 67 MUZ-LN50VGHZ Jumper wire for pre-heat control setting (JK) LEV (CN724) Jumper wire for changing defrost setting (JS) Ambient temperature thermistor/RT65 (CN672) Heater (CN601) 230 V AC Outdoor heat exchanger temperature thermistor R.V. coil (CN602) /RT68 (CN671) 230 V AC Discharge temperature thermistor/RT62 (CN671) Defrost thermistor...
Page 68 MUZ-LN50VGHZ2 Back side of unit Smoothing Smoothing Smoothing Output to drive Capacitor Capacitor Capacitor Fuse (F880) outdoor fan motor Heater (CN601) (CB1) (CB2) (CB3) T3.15AL250V (CN932) 230 V AC Fuse (F601) T3.15AL250V 230 V AC R.V. coil/ 21S4 (CN602) 230 V AC Fuse (F62) 15 A 250 V Fuse (F901)
Page 69: Disassembly Instructions
DISASSEMBLY INSTRUCTIONS <Detaching method of the terminal with locking mechanism> The terminal which has the locking mechanism can be detached as shown below. There are 2 types of the terminal with locking mechanism. The terminal without locking mechanism can be detached by pulling it out. Check the shape of the terminal before detaching.
Page 70 OPERATING PROCEDURE PHOTOS/FIGURES 2. Removing the inverter assembly and inverter P.C. Photo 4 Screw of the P.B. support board and the separator Ambient temperature (1) Remove the cabinet and panels. (Refer to section 1.) Screws of thermistor (2) Disconnect the lead wire to the reactor and the following con- the terminal block nectors: support and...
Page 71 OPERATING PROCEDURE PHOTOS/FIGURES 3. Removing R.V. coil Photo 8 (1) Remove the cabinet and panels. (Refer to section 1.) (2) Disconnect the following connectors: Outdoor heat <Inverter P.C. board> exchanger tempera- CN721 (R.V. coil) ture thermistor (3) Remove the R.V. coil. Defrost thermistor 4.
Page 72 OPERATING PROCEDURE PHOTOS/FIGURES 6. Removing the compressor and 4-way valve Photo 10 (1) Remove the cabinet and panels. (Refer to section 1.) Discharge pipe Suction pipe (2) Remove the inverter assembly. (Refer to section 2.) brazed part brazed part (3) Recover gas from the refrigerant circuit. NOTE: Recover gas from the pipes until the pressure gauge shows 0 kg/cm...
Page 73 13-2. MUZ-LN25VGHZ2 - MUZ-LN35VGHZ2 - NOTE: Turn OFF the power supply before disassembly. : Indicates the visible parts in the photos. : Indicates the invisible parts in the photos. OPERATING PROCEDURE PHOTOS/FIGURES 1. Removing the cabinet Photo 1 Screws of (1) Remove the screws fixing the service panel.
Page 74 OPERATING PROCEDURE PHOTOS/FIGURES 2. Removing the inverter assembly and inverter P.C. Photo 4 Screw of the P.B. support board and the separator Ambient temperature (1) Remove the cabinet and panels (refer to section 1). Screws of thermistor (2) Disconnect the lead wire to the reactor and the following con- the terminal block nectors: support and...
Page 75 OPERATING PROCEDURE PHOTOS/FIGURES 3. Removing R. V. coil Photo 8 (1) Remove the cabinet and panels (refer to section 1). (2) Disconnect the following connectors: Outdoor heat <Inverter P.C. board> exchanger tempera- CN721 (R.V. coil) ture thermistor (3) Remove the R.V. coil. Defrost thermistor 4.
Page 76 OPERATING PROCEDURE PHOTOS/FIGURES 6. Removing the compressor and 4-way valve Photo 10 (1) Remove the cabinet and panels (refer to section 1). Compressor protector Discharge pipe Suction pipe (2) Remove the inverter assembly (refer to section 2). brazed part brazed part (3) Recover gas from the refrigerant circuit.
Page 77 13-3. MUZ-LN50VGHZ NOTE: Turn OFF the power supply before disassembly. OPERATING PROCEDURE PHOTOS/FIGURES 1. Removing the cabinet Photo 1 (1) Remove the screws of the service panel. Screws of the top panel (2) Remove the screws of the top panel. (3) Remove the screw of the valve cover.
Page 78 OPERATING PROCEDURE PHOTOS/FIGURES 2. Removing the inverter assembly and inverter P.C. Photo 3 Screws of the relay panel board Inverter P.C board (1) Remove the cabinet and the service panel. (Refer to section (2) Disconnect the lead wire to the reactor and the following connectors: <Inverter P.C.
Page 79 OPERATING PROCEDURE PHOTOS 3. Removing R.V. coil Photo 5 Screw of (1) Remove the cabinet and panels. (Refer to section 1.) the R.V. coil (2) Disconnect the following connector: <Inverter P.C. board> CN602 (R.V. coil) (3) Remove the R.V. coil. Brazed parts of 4-way valve 4.
Page 80 OPERATING PROCEDURE PHOTOS/FIGURES 5. Removing outdoor fan motor Photo 7 (1) Remove the top panel, cabinet and service panel. (Refer to Propeller fan section 1.) (2) Disconnect the following connectors: <Inverter P.C. board> Propeller fan CN931, CN932 (Fan motor) (3) Remove the propeller fan nut. (4) Remove the propeller fan.
Page 81 13-4. MUZ-LN50VGHZ2 NOTE: Turn OFF the power supply before disassembly. OPERATING PROCEDURE PHOTOS/FIGURES 1. Removing the cabinet Photo 1 (1) Remove the screws of the service panel. (2) Remove the screws of the top panel. Screws of the top panel (3) Remove the screw of the valve cover.
Page 82 OPERATING PROCEDURE PHOTOS/FIGURES 2. Removing the inverter assembly and inverter P.C. Photo 3 board Screw of the heat sink Lead wires of the (1) Remove the cabinet and panels. (Refer to section 1.) support and the separator reactor (2) Disconnect the lead wire to the reactor and the following connectors: <Inverter P.C.
Page 83 OPERATING PROCEDURE PHOTOS/FIGURES Connection procedure when attaching the inverter P.C. Photo 5 board (Photo 6, 7) 1. Attach the heat sink support to the P.C. board support. 2. Hook the lead wires of the compressor, the reactor and the P.C. board to each hooks on the heat sink support as shown Photo 7.
Page 84 OPERATING PROCEDURE PHOTOS/FIGURES 3. Removing the discharge temperature thermistor, Photo 8 Outdoor heat exchanger defrost thermistor, outdoor heat exchanger tempera- temperature thermistor ture thermistor and ambient temperature thermistor (1) Remove the cabinet and panels. (Refer to section 1.) (2) Disconnect the lead wire to the reactor and the following connectors: <Inverter P.C.
Page 85 OPERATING PROCEDURE PHOTOS/FIGURES 5. Removing the compressor and 4-way valve Photo 10 (1) Remove the top panel, cabinet and service panel. (Refer to Brazed part of Brazed part of section 1.) the discharge pipe the suction pipe (2) Remove the back panel. (Refer to section 1.) (3) Remove the inverter assembly.
Page 86 HEAD OFFICE: TOKYO BUILDING, 2-7-3, MARUNOUCHI, CHIYODA-KU, TOKYO 100-8310, JAPAN © Copyright 2017 MITSUBISHI ELECTRIC CORPORATION Issued: Dec. 2022. No. OBH768 REVISED EDITION-G Issued: Jun. 2021. No. OBH768 REVISED EDITION-F Issued: Feb. 2021. No. OBH768 REVISED EDITION-E Issued: Dec. 2020. No. OBH768 REVISED EDITION-D Issued: Jul.

Mitsubishi Electric MUZ-LN35VGHZ2-E1 Service Manual

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