Mitsubishi Electric MUZ-LN25VGHZ Service Manual
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Mitsubishi Electric MUZ-LN25VGHZ Service Manual

Outdoor unit
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OUTDOOR UNIT

SERVICE MANUAL

Models
MUZ-LN25VGHZ
MUZ-LN35VGHZ
MUZ-LN50VGHZ
MUZ-LN25VGHZ
MUZ-LN35VGHZ
NOTE:
RoHS compliant products have <G> mark on the spec name plate.
HFC
utilized
R32
-
E1
ER1
ET1
,
,
-
E1
ER1
ET1
,
,
-
E1
ER1
ET1
,
,
Indoor unit service manual
MSZ-LN•VGW/V/B/R Series (OBH766)
CONTENTS
1. TECHNICAL CHANGES ··································· 2
USING REFRIGERANT R32 ····························· 3
3. PART NAMES AND FUNCTIONS ····················· 5
4. SPECIFICATION ················································ 6
5. NOISE CRITERIA CURVES ······························ 9
6. OUTLINES AND DIMENSIONS ······················ 10
7. WIRING DIAGRAM ·········································· 12
8. REFRIGERANT SYSTEM DIAGRAM ············· 14
9. PERFORMANCE CURVES ····························· 16
10. ACTUATOR CONTROL ··································· 28
11. SERVICE FUNCTIONS ···································· 29
12. TROUBLESHOOTING ····································· 30
13. DISASSEMBLY INSTRUCTIONS ···················· 51
PARTS CATALOG (OBB768)
No. OBH768

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Summary of Contents for Mitsubishi Electric MUZ-LN25VGHZ

  • Page 1: Table Of Contents

    OUTDOOR UNIT No. OBH768 SERVICE MANUAL utilized Models MUZ-LN25VGHZ MUZ-LN35VGHZ MUZ-LN50VGHZ Indoor unit service manual MSZ-LN•VGW/V/B/R Series (OBH766) CONTENTS 1. TECHNICAL CHANGES ··································· 2 2. SERVICING PRECAUTIONS FOR UNITS USING REFRIGERANT R32 ····························· 3 3. PART NAMES AND FUNCTIONS ····················· 5 4.

  • Page 2: Technical Changes

    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. TECHNICAL CHANGES MUZ-LN25VGHZ - MUZ-LN35VGHZ - MUZ-LN50VGHZ - 1. New model...

  • Page 3: 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 4 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 5: Part Names And Functions

    PART NAMES AND FUNCTIONS MUZ-LN25VGHZ MUZ-LN35VGHZ 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 OBH768...

  • Page 6: Specification

    SPECIFICATION Outdoor model MUZ-LN25VGHZ MUZ-LN35VGHZ Power supply Single phase, 230 V, 50 Hz Cooling 2.5 (0.8 - 3.5) 3.5 (0.8 - 4.0) Capacity Rated frequency (Min.-Max.) Heating 3.2 (1.0 - 6.3) 4.0 (1.0 - 6.6) Breaker Capacity Cooling Power input 1 (Set)
  • Page 7 Outdoor model MUZ-LN50VGHZ Power supply Single phase, 230 V, 50 Hz Cooling 5.0 (1.4 - 5.8) Capacity Rated frequency (Min. - Max.) Heating 6.0 (1.8 - 8.7) Breaker Capacity Cooling 1,380 Power input 1 (Set) Heating 1,430 Cooling Running current 1 (Set) Heating Cooling Power factor 1 (Set)
  • Page 8 Specifi cations and rated conditions of main electric parts Model MUZ-LN25VGHZ MUZ-LN35VGHZ Item (C62, C63) 600 μF/ 620 μF 420 V Smoothing capacitor (C61, C62, C63) 600 μF/ 620 μF 420 V (DB61) 15 A 600 V Diode module (DB65)

  • Page 9: Noise Criteria Curves

    NOISE CRITERIA CURVES MUZ-LN25VGHZ MUZ-LN35VGHZ 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...

  • Page 10: Outlines And Dimensions

    OUTLINES AND DIMENSIONS MUZ-LN25VGHZ MUZ-LN35VGHZ Unit: mm OBH768...
  • Page 11 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 12: Wiring Diagram

    WIRING DIAGRAM MUZ-LN25VGHZ MUZ-LN35VGHZ OBH768...
  • Page 13 MUZ-LN50VGHZ OBH768...

  • Page 14: Refrigerant System Diagram

    REFRIGERANT SYSTEM DIAGRAM Unit: mm MUZ-LN25VGHZ MUZ-LN35VGHZ 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...
  • Page 15 MAX. REFRIGERANT PIPING LENGTH and MAX. HEIGHT DIFFERENCE Refrigerant piping: m Piping size O.D: mm Model Max. Length A Max. Height difference B Liquid MUZ-LN25VGHZ 9.52 6.35 MUZ-LN35VGHZ 9.52 6.35 MUZ-LN50VGHZ Indoor unit Max. Height difference Max. Length Outdoor unit...

  • Page 16: Performance Curves

    PERFORMANCE CURVES MUZ-LN25VGHZ MUZ-LN35VGHZ MUZ-LN50VGHZ 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 17 Total input (Cooling : at Rated frequency Indoor intake air Wet-bulb temperature( ) Outdoor intake air Dry-bulb temperature (°C) Heating capacity (at Rated frequency) 14.5 19.1 25.0 13.4 17.6 23.1 12.3 16.2 21.1 11.2 14.7 19.2 10.1 13.2 17.3 11.7 15.4 10.3 13.5...
  • Page 18 9-2. CAPACITY AND INPUT CORRECTION BY OPERATIONAL FREQUENCY OF COMPRESSOR MUZ-LN25VGHZ Correction of Heating input Correction of Cooling capacity Correction of Cooling input Correction of Heating capacity The operational frequency The operational frequency The operational frequency The operational frequency of compressor (Hz)

  • Page 19: Cool Operation

    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-LN35VGHZ MUZ-LN50VGHZ (kgf/cm [Gauge])(MPa [Gauge]) (kgf/cm [Gauge])(MPa [Gauge]) (kgf/cm [Gauge])(MPa [Gauge]) 1.16...

  • Page 20: Heat Operation

    HEAT operation Condition: Indoor Outdoor Dry bulb temperature (°C) 20.0 20.0 Wet bulb temperature (°C) 14.5 14.5 Operation: Test run operation (Refer to 9-3.) Outdoor unit current MUZ-LN25VGHZ MUZ-LN35VGHZ MUZ-LN50VGHZ Ambient temperature (°C) Ambient temperature (°C) Ambient temperature (°C) OBH768...
  • Page 21 PERFORMANCE DATA COOL operation a t Rated frequency 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...
  • Page 22 PERFORMANCE DATA COOL operation a t Rated frequency 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...
  • Page 23 PERFORMANCE DATA COOL operation a t Rated frequency 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 24 PERFORMANCE DATA COOL operation a t Rated frequency 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 25 PERFORMANCE DATA COOL operation a t Rated frequency 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 26 PERFORMANCE DATA COOL operation a t Rated frequency 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 27 PERFORMANCE DATA HEAT operation at Rated frequency MUZ-LN25VGHZ CAPACITY: 3.2 kW INPUT: 580 W OUTDOOR WB (°C) INDOOR DB (°C) INPUT INPUT INPUT INPUT INPUT INPUT INPUT 2.02 2.43 2.85 3.26 3.68 4.06 4.48 1.92 2.30 2.72 3.10 3.52 3.90 4.30...

  • Page 28: Actuator Control

    ACTUATOR CONTROL MUZ-LN25VGHZ MUZ-LN35VGHZ MUZ-LN50VGHZ 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.

  • Page 29: Service Functions

    SERVICE FUNCTIONS MUZ-LN25VGHZ MUZ-LN35VGHZ MUZ-LN50VGHZ 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 fi nish temperature (°C) Jumper wire...

  • Page 30: Troubleshooting

    TROUBLESHOOTING MUZ-LN25VGHZ MUZ-LN35VGHZ MUZ-LN50VGHZ 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 31 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. 1.
  • Page 32 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 33 NOTE: Blinking patterns of this mode differ from the ones of 3. Outdoor unit failure recall mode table 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.
  • Page 34 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 fl...
  • Page 35 12-3. TROUBLESHOOTING CHECK TABLE Abnormal point/ Con- Symptom LED indication Condition Remedy dition 1-time fl ash every Outdoor power sys- Overcurrent protection cut-out operates 3 consecutive times • Reconnect connector of compres- 2.5 seconds within 1 minute after the compressor gets started. sor.
  • Page 36 Abnormal point/ Con- Symptom LED indication Condition Remedy dition Outdoor unit 7-time fl ash Low discharge tem- Temperature of discharge temperature thermistor has been • Refer to 12-5. "Check of LEV". operates. 2.5 seconds OFF perature protection 50°C or less for 20 minutes. •...
  • Page 37 12-4. TROUBLE CRITERION OF MAIN PARTS MUZ-LN25VGHZ MUZ-LN35VGHZ MUZ-LN50VGHZ Part name Check method and criterion Figure Defrost thermistor (RT61) Fin temperature thermistor (RT64) Measure the resistance with a tester. Ambient temperature Refer to 12-6. “Test point diagram and voltage”, 1. “Inverter P.C.
  • Page 38 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”. Are the voltages balanced? Replace the inverter P.C. board. Check the compressor. See 12-5.
  • Page 39 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>>...
  • Page 40 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 41 H Check of R.V. coil MUZ-LN25/35VGHZ 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 42 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 43 J Check of power supply Disconnect the connector between the compressor and the power module (IC700). Turn ON power supply and press EMERGENCY OPERATION Rectify indoor/outdoor switch. connecting wire. Is there voltage 230VAC Replace the indoor Does POWER lamp on the indoor between the indoor terminal electronic control P.C.
  • Page 44 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 45 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 46 M How to check miswiring and serial signal error NOTE: Refer to the indoor unit service manual. 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)?
  • Page 47 N Check of the outdoor refrigerant circuit The unit occasionally stops when the Was the operation started with Has the operation stopped stop valve is opened or closed during the stop valve closed, and was during pump down? operation. Open the stop valve and it opened during operation? start the cooling operation again.
  • Page 48 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 49 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) DB61 Back side of unit (C63) (C62) (C61) 230VAC 260 - 370VDC Fuse (F701) (LN35VGHZ) T3.15AL250V 230\VAC Fuse (F801) T3.15AL250V...
  • Page 50 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) 230VAC Outdoor heat exchanger temperature thermistor R.V. coil (CN602) /RT68 (CN671) 230VAC Discharge temperature thermistor/RT62 (CN671) Defrost thermistor /RT61 (CN671) Fuse (F601) Fin temperature...

  • Page 51: Disassembly Instructions

    Pull the terminal while pull out the terminal pushing the locking slowly. Locking lever lever. Connector 13-1. MUZ-LN25VGHZ MUZ-LN35VGHZ NOTE: Turn OFF the power supply before disassembly. OPERATING PROCEDURE PHOTOS 1. Removing the cabinet Photo 1 Screws of (1) Remove the screws fixing the service panel.
  • Page 52 OPERATING PROCEDURE PHOTOS 2. Removing the inverter assembly and inverter P.C. Photo 4 Screw of the P.B. support and the separator board (1) Remove the cabinet and panels. (Refer to 1.) Screws of Screw of the heat sink (2) Disconnect the lead wire to the reactor and the following con- the terminal block support and the separator nectors:...
  • Page 53 OPERATING PROCEDURE PHOTOS 3. Removing R. V. coil Photo 7 (1) Remove the cabinet and panels. (Refer to 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. 4.
  • Page 54 OPERATING PROCEDURE PHOTOS 6. Removing the compressor and 4-way valve Photo 9 (1) Remove the cabinet and panels. (Refer to 1.) Discharge pipe Suction pipe (2) Remove the inverter assembly. (Refer to 2.) brazed part brazed part (3) Recover gas from the refrigerant circuit. Recover gas from the pipes until the pressure NOTE: gauge shows 0 kg/cm...
  • Page 55 13-2. MUZ-LN50VGHZ NOTE: Turn OFF the power supply before disassembly. OPERATING PROCEDURE PHOTOS 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 56 OPERATING PROCEDURE PHOTOS 2. Removing the inverter assembly and inverter P.C. Photo 3 Screws of the relay panel Inverter P.C board board (1) Remove the cabinet and the service panel. (Refer to 1.) (2) Disconnect the lead wire to the reactor and the following connectors: <Inverter P.C.
  • Page 57 OPERATING PROCEDURE PHOTOS 3. Removing R.V. coil Photo 5 Screw of (1) Remove the cabinet and panels. (Refer to 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 58 Discharge temperature Brazed part of thermistor the suction pipe HEAD OFFICE: TOKYO BUILDING, 2-7-3, MARUNOUCHI, CHIYODA-KU, TOKYO 100-8310, JAPAN © Copyright 2017 MITSUBISHI ELECTRIC CORPORATION Published: Feb. 2017. No. OBH768 Specifications are subject to change without notice. Made in Japan...

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