Mitsubishi Electric MUZ-GL09NA-U2 Service Manual

Mitsubishi Electric MUZ-GL09NA-U2 Service Manual

Outdoor unit
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INDOOR UNIT
OUTDOOR UNIT
SERVICE MANUAL
Models
MUZ-GL09NA -
U1
MUZ-GL12NA -
U1
MUZ-GL15NA -
U1
MUZ-GL18NA -
U1
MUZ-GL24NA -
U1
MUZ-GL18/24NA
MUZ-GL18/24NAH
MUY-GL18/24NA
MUZ-GL09NAH -
,
,
U2
U8
MUZ-GL12NAH -
,
U2
MUZ-GL15NAH -
,
U2
MUZ-GL18NAH -
MUZ-GL24NAH -
,
U2
Revision G:
• MUZ-GL09/12/15NA(H)-
MUY-GL09/12/15NA-
OBH733 REVISED EDITION-F is void.
HFC
utilized
R410A
MUY-GL09NA -
,
,
U1
U2
U8
MUY-GL12NA -
,
U1
U2
MUY-GL15NA -
,
U1
U2
MUY-GL18NA -
U1
MUY-GL24NA -
U1
Indoor unit service manual
MSZ-GL•NA, MSY-GL•NA Series (OBH732)
CONTENTS
1. TECHNICAL CHANGES ··································· 2
2. PART NAMES AND FUNCTIONS ····················· 3
3. SPECIFICATION ················································ 4
4. OUTLINES AND DIMENSIONS ························ 7
5. WIRING DIAGRAM ············································ 9
6. REFRIGERANT SYSTEM DIAGRAM ············· 21
7. DATA ································································ 24
8. ACTUATOR CONTROL ··································· 39
9. SERVICE FUNCTIONS ··································· 40
10. TROUBLESHOOTING ····································· 41
11. DISASSEMBLY INSTRUCTIONS ···················· 65
PARTS CATALOG (OBB733)
and
U2
have been added.
U2
No. OBH733
REVISED EDITION-G
,
U1
U2
,
U1
U2
,
U1
U2
U1
U1

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Summary of Contents for Mitsubishi Electric MUZ-GL09NA-U2

  • Page 1 Revision G: • MUZ-GL09/12/15NA(H)- MUY-GL09/12/15NA- have been added. OBH733 REVISED EDITION-F is void. INDOOR UNIT OUTDOOR UNIT No. OBH733 utilized REVISED EDITION-G SERVICE MANUAL R410A Models MUZ-GL09NA - MUZ-GL09NAH - MUY-GL09NA - MUZ-GL12NA - MUZ-GL12NAH - MUY-GL12NA - MUZ-GL15NA - MUZ-GL15NAH - MUY-GL15NA - MUZ-GL18NA -...
  • 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 PART NAMES AND FUNCTIONS MUZ-GL09NA MUZ-GL09NAH MUY-GL09NA MUZ-GL12NA MUZ-GL12NAH MUY-GL12NA MUZ-GL15NA MUZ-GL15NAH MUY-GL15NA Air inlet (back and side) Piping Air outlet Drain hose Drain outlet MUZ-GL18NA MUZ-GL18NAH MUY-GL18NA MUZ-GL24NA MUZ-GL24NAH MUY-GL24NA Air inlet (back and side) Piping Drain hose Air outlet Drain outlet OBH733G...
  • Page 4 SPECIFICATION MUZ- MUY- MUZ- MUY- Outdoor unit model GL09NA- GL09NA- GL09NA- GL12NA GL09NA- GL09NA- GL12NA GL09NAH- GL09NAH- GL09NAH- GL12NAH Btu/h 9,000 (3,600 - 12,200) 12,000 (1,500 - 13,600) Cooling 1 Capacity 10,900 10,900 14,400 Rated (Minimum~Maximum) Btu/h Heating 47 1 (MUZ) (4,500 - 15,900) (4,500 - 14,100) (2,000 - 18,100)
  • Page 5 MUZ- MUY- MUZ- MUY- MUZ- MUY- Outdoor unit model GL15NA GL18NA GL24NA GL15NA GL18NA GL24NA GL15NAH GL18NAH GL24NAH Btu/h 14,000 (3,100 - 18,200) 18,000 (5,800 ~ 22,000) 22,500 (8,200 ~ 31,400) Cooling 1 Capacity 18,000 21,600 27,600 Btu/h Rated (Minimum~Maximum) Heating 47 1 (MUZ) (4,800 - 20,900) (5,400 ~ 25,000)
  • Page 6 Test condition 3, 4 Indoor air condition (°F) Outdoor air condition (°F) Mode Test Dry bulb Wet bulb Dry bulb Wet bulb "A-2" Cooling Steady State (75) at rated compressor Speed "B-2" Cooling Steady State (65) at rated compressor Speed SEER "B-1"...
  • Page 7 OUTLINES AND DIMENSIONS Unit: inch MUZ-GL09NA MUZ-GL09NAH MUY-GL09NA MUZ-GL12NA MUZ-GL12NAH MUY-GL12NA MUZ-GL15NA MUZ-GL15NAH MUY-GL15NA REQUIRED SPACE 4 in. (100 mm) or more when front and sides of the unit are clear (GL09/12/15NA) (GL09/12/15NAH) When any 2 sides of left, right and rear of the unit are clear holes Liquid refrigerant pipe joint...
  • Page 8 MUZ-GL18NA MUZ-GL18NAH MUY-GL18NA Unit: inch MUZ-GL24NA MUZ-GL24NAH MUY-GL24NA REQUIRED SPACE *1 20 in. (500 mm) or more when front and sides of the unit are clear 16-7/16 Air in 1-9/16 Air in Air out 2-holes 13/32 13/16 6-7/8 19-11/16 *2 When any 2 sides of left, right and rear of the unit are clear 3-3/16 33-1/16...
  • Page 9 WIRING DIAGRAM MUZ-GL09NA- MUZ-GL12NA- MUZ-GL09NA- MUZ-GL12NA- OBH733G...
  • Page 10 MUZ-GL09NAH- MUZ-GL12NAH- MUZ-GL09NAH- MUZ-GL12NAH- OBH733G...
  • Page 11 MUY-GL09NA- MUY-GL12NA- MUY-GL09NA- MUY-GL12NA- OBH733G...
  • Page 12 MUZ-GL15NA- MUZ-GL15NA- OBH733G...
  • Page 13 MUZ-GL15NAH- MUZ-GL15NAH- OBH733G...
  • Page 14 MUY-GL15NA- MUY-GL15NA- OBH733G...
  • Page 15 MUZ-GL18NA OBH733G...
  • Page 16 MUZ-GL18NAH OBH733G...
  • Page 17 MUY-GL18NA OBH733G...
  • Page 18 MUZ-GL24NA OBH733G...
  • Page 19 MUZ-GL24NAH OBH733G...
  • Page 20 MUY-GL24NA OBH733G...
  • Page 21 REFRIGERANT SYSTEM DIAGRAM MUZ-GL09NA MUZ-GL09NAH MUY-GL09NA Unit: Inch (mm) MUZ-GL12NA MUZ-GL12NAH MUY-GL12NA MUZ-GL15NA MUZ-GL15NAH MUY-GL15NA Refrigerant pipe ø3/8 (ø9.52) (GL09/12) ø1/2 (ø12.7) (GL15) 4-way valve (with heat insulator) Muffler Outdoor heat exchanger Stop valve temperature (with service port) thermistor Outdoor Muffler Discharge heat...
  • Page 22 MUZ-GL24NA - MUY-GL24NA Unit: inch Muffler Refrigerant pipe ø 5/8 ( ø15.88) with #100 mesh strainer 4-way valve (with heat insulator) Service port Stop valve (with service port) Outdoor Flared connection Discharge heat Ambient temperature exchanger temperature thermistor Defrost Service thermistor RT62 thermistor...
  • Page 23: Table Of Contents

    MAX. REFRIGERANT PIPING LENGTH and MAX. HEIGHT DIFFERENCE Refrigerant piping: ft. Piping size O.D: in. Model Max. Length Max. Height difference Liquid MUZ-GL09NA MUZ-GL09NAH MUY-GL09NA MUZ-GL12NA MUZ-GL12NAH MUY-GL12NA MUZ-GL15NA MUZ-GL15NAH MUY-GL15NA MUZ-GL18NA MUZ-GL18NAH MUY-GL18NA MUZ-GL24NA MUZ-GL24NAH MUY-GL24NA Indoor unit Max. Height difference Max.
  • Page 24 NOTE: Refrigerant piping exceeding 25 ft. requires additional refrigerant charge according to the calculation. Refrigerant piping length (one way): ft. Outdoor unit Model precharged MUZ-GL18NA MUZ-GL18NAH 3 lb. 9 oz. 1.08 3.24 5.40 7.56 9.72 11.88 14.04 16.20 MUY-GL18NA Calculation: X oz. = 1.08/5 oz./ft. × (Refrigerant piping length (ft.) - 25) NOTE: Refrigerant piping exceeding 33 ft.
  • Page 25: Muz-Gl09Na

    2) COOLING CAPACITY CORRECTIONS Refrigerant piping length (one way: ft.) 25 (std.) MUZ-GL09NA MUZ-GL09NAH MUY-GL09NA MUZ-GL12NA MUZ-GL12NAH 0.988 0.967 MUY-GL12NA MUZ-GL15NA MUZ-GL15NAH MUY-GL15NA MUZ-GL18NA MUZ-GL18NAH 0.985 0.963 0.933 MUY-GL18NA MUZ-GL24NA MUZ-GL24NAH 0.983 0.956 0.921 MUY-GL24NA 3) HEATING CAPACITY CORRECTIONS Refrigerant piping length (one way: ft.) 25 (std.) MUZ-GL09NA MUZ-GL09NAH...
  • Page 26 4) HEATING CAPACITY (MUZ) Indoor air Outdoor intake air WB temperature (˚F) Model IDB (˚F) 0.42 0.54 0.63 0.70 10.6 0.74 11.0 0.75 12.4 0.78 MUZ-GL09NA 0.41 0.52 0.62 0.68 10.9 0.72 11.2 0.73 12.7 0.76 0.39 0.50 0.59 10.0 0.67 11.2 0.70...
  • Page 27: Muz-Gl24Na Muz-Gl24Nah Muy-Gl24Na

    7-2. PERFORMANCE CURVE Cooling Cooling capacity (at Rated frequency) Indoor intake air Wet-bulb temperature( F) Outdoor intake air DB temperature(°F) MUZ-GL09NA MUZ-GL09NAH MUY-GL09NA SHF at rating condition = 0.82 = 399 CFM Airflow Outdoor intake air DB temperature (°F) MUZ-GL12NA MUZ-GL12NAH MUY-GL12NA MUZ-GL15NA MUZ-GL15NAH MUY-GL15NA SHF at rating condition = 0.77 SHF at rating condition = 0.78...
  • Page 28 Heating Heating capacity (at Rated frequency) Outdoor intake air WB temperature (°F) MUZ-GL09NA MUZ-GL09NAH Airflow = 406 CFM Airflow = 406 CFM Outdoor intake air WB temperature (°F) Outdoor intake air WB temperature (°F) MUZ-GL12NA MUZ-GL12NAH Airflow = 406 CFM Airflow = 406 CFM Outdoor intake air WB temperature (°F)
  • Page 29 MUZ-GL18NA MUZ-GL18NAH = 646 CFM = 646 CFM Airflow Airflow Outdoor intake air WB temperature (°F) Outdoor intake air WB temperature (°F) MUZ-GL24NA MUZ-GL24NAH Airflow = 738 CFM = 738 CFM Airflow Outdoor intake air WB temperature (°F) Outdoor intake air WB temperature (°F) This value of frequency is not the same as the actual frequency in operating.
  • Page 30 7-3. CONDENSING PRESSURE Cooling Data are based on the condition of indoor humidity 50 %. Airflow should be set to High speed. MUZ-GL09NA MUZ-GL09NAH MUY-GL09NA (PSIG) (PSIG) 100 105 (°F) (°F) Outdoor ambient temperature Outdoor ambient temperature MUZ-GL12NA MUZ-GL12NAH MUY-GL12NA (PSIG) (PSIG) 100 105...
  • Page 31 MUZ-GL18NA MUZ-GL18NAH MUY-GL18NA (PSIG) (PSIG) 100 105 (°F) (°F) Outdoor ambient temperature Outdoor ambient temperature MUZ-GL24NA MUZ-GL24NAH MUY-GL24NA (PSIG) (PSIG) 68 70 100 105 (°F) 68 70 100 105 (°F) Outdoor ambient temperature Outdoor ambient temperature OBH733G...
  • Page 32 Heating Data are based on the condition of outdoor humidity 75%. Airflow should be set to High speed. Data are for heating operation without any frost. MUZ-GL09NA - MUZ-GL09NAH - (PSIG) (PSIG) 58Hz 58Hz (°F) (°F) Outdoor ambient temperature Outdoor ambient temperature MUZ-GL09NA - MUZ-GL09NAH - MUZ-GL12NA MUZ-GL12NAH...
  • Page 33 MUZ-GL15NA MUZ-GL15NAH (PSIG) (PSIG) 58Hz 58Hz (°F) (°F) Outdoor ambient temperature Outdoor ambient temperature MUZ-GL18NA MUZ-GL18NAH (PSIG) (PSIG) 81Hz 81Hz (°F) (°F) Outdoor ambient temperature Outdoor ambient temperature MUZ-GL24NA MUZ-GL24NAH (PSIG) (PSIG) 58Hz 58Hz (°F) (°F) Outdoor ambient temperature Outdoor ambient temperature OBH733G...
  • Page 34: Indoor Unit

    7-4. STANDARD OPERATION DATA MSZ-GL09NA - MSY-GL09NA - Model MSZ-GL09NA - MSZ-GL09NA - MSY-GL09NA - Item Unit Cooling Heating Cooling Heating Cooling Capacity Btu/h 9,000 10,900 9,000 10,900 9,000 — 0.82 — 0.82 — 0.82 Input 0.585 0.72 0.585 0.72 0.585 Rated 59.5...
  • Page 35: Outdoor Unit

    Model MSZ-GL12NA MSY-GL12NA MSZ-GL15NA MSY-GL15NA Item Unit Cooling Heating Cooling Cooling Heating Cooling Capacity Btu/h 12,000 14,400 12,000 14,000 18,000 14,000 — 0.77 — 0.77 0.78 — 0.78 Input 0.920 1.10 0.920 1.080 1.60 1.080 Rated 56.5 56.5 Indoor unit MSZ-GL12NA MSY-GL12NA MSZ-GL15NA...
  • Page 36 Model MSZ-GL18NA MSY-GL18NA MSZ-GL24NA MSY-GL24NA Item Unit Cooling Heating Cooling Cooling Heating Cooling Capacity Btu/h 18,000 21,600 18,000 22,500 27,600 22,500 — 0.87 — 0.87 0.75 — 0.75 Input 1.34 1.68 1.34 1.80 2.34 1.80 Rated 67.5 82.0 67.5 Indoor unit MSZ-GL18NA MSY-GL18NA MSZ-GL24NA...
  • Page 37: Muz-Gl09Na - U1

    7-5. CAPACITY AND INPUT CORRECTION BY INVERTER OUTPUT FREQUENCY MUZ-GL09NA - MUZ-GL09NAH- Correction of Cooling capacity Correction of Cooling total input Correction of Heating capacity Correction of Heating total input (Hz) (Hz) (Hz) (Hz) The operational frequency of compressor The operational frequency of compressor The operational frequency of compressor The operational frequency of compressor MUY-GL09NA...
  • Page 38: Muz-Gl12Na Muz-Gl12Nah

    MUZ-GL15NA MUZ-GL15NAH MUY-GL15NA MUZ-GL15NA MUZ-GL15NAH Correction of Cooling capacity Correction of Cooling total input Correction of Heating capacity Correction of Heating total input (Hz) (Hz) (Hz) (Hz) The operational frequency of compressor The operational frequency of compressor The operational frequency of compressor The operational frequency of compressor MUZ-GL18NA MUZ-GL18NAH MUY-GL18NA MUZ-GL18NA MUZ-GL18NAH...
  • Page 39 ACTUATOR CONTROL MUZ-GL09NA MUZ-GL09NAH MUY-GL09NA MUZ-GL12NA MUZ-GL12NAH MUY-GL12NA MUZ-GL15NA MUZ-GL15NAH MUY-GL15NA MUZ-GL18NA MUZ-GL18NAH MUY-GL18NA MUZ-GL24NA MUZ-GL24NAH MUY-GL24NA 8-1. 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 40 SERVICE FUNCTIONS MUZ-GL09NA MUZ-GL09NAH MUY-GL09NA MUZ-GL12NA MUZ-GL12NAH MUY-GL12NA MUZ-GL15NA MUZ-GL15NAH MUY-GL15NA MUZ-GL18NA MUZ-GL18NAH MUY-GL18NA MUZ-GL24NA MUZ-GL24NAH MUY-GL24NA 9-1. CHANGE IN DEFROST SETTING (MUZ) 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 10-6.1.). Defrost finish temperature Jumper MUZ-GL09/12/15NA...
  • Page 41 TROUBLESHOOTING MUZ-GL09NA MUZ-GL09NAH MUY-GL09NA MUZ-GL12NA MUZ-GL12NAH MUY-GL12NA MUZ-GL15NA MUZ-GL15NAH MUY-GL15NA MUZ-GL18NA MUZ-GL18NAH MUY-GL18NA MUZ-GL24NA MUZ-GL24NAH MUY-GL24NA 10-1. 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.
  • Page 42 10-2. 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 (10-3.) disappears, the memorized failure details can be recalled. 1.
  • Page 43 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 44 NOTE: Blinking patterns of this mode differ from the ones of TROUBLESHOOTING CHECK TABLE (10-3.). 3. Table of outdoor unit failure mode recall function The upper lamp of the Indoor/outdoor Outdoor unit OPERATION Abnormal point LED indication unit failure Condition Remedy failure mode INDICATOR...
  • Page 45 NOTE: Blinking patterns of this mode differ from the ones of TROUBLESHOOTING CHECK TABLE (10-3.). The upper lamp of the Indoor/outdoor Outdoor unit OPERATION Abnormal point LED indication unit failure Condition Remedy failure mode INDICATOR (Failure mode/protection) (Outdoor P.C. board) mode recall recall function lamp...
  • Page 46 10-3. TROUBLESHOOTING CHECK TABLE Abnormal point/ Symptom LED indication Condition Remedy Condition 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 47 Abnormal point/ Symptom LED indication Condition Remedy Condition Outdoor unit 1-time blink Frequency drop by MUZ-GL09/12/15/18 When the input current exceeds ap- The unit is normal, but check the operates. 2.5 seconds OFF current protection MUY-GL09/12/15/18 proximately 10.5A, compressor fre- following.
  • Page 48 10-4. TROUBLE CRITERION OF MAIN PARTS MUZ-GL09NA MUZ-GL09NAH MUY-GL09NA MUZ-GL12NA MUZ-GL12NAH MUY-GL12NA MUZ-GL15NA MUZ-GL15NAH MUY-GL15NA MUZ-GL18NA MUZ-GL18NAH MUY-GL18NA MUZ-GL24NA MUZ-GL24NAH MUY-GL24NA Part name Check method and criterion Figure Measure the resistance with a tester. Defrost thermistor (RT61) (MUZ) Refer to 10-6. “Test point diagram and voltage”, 1. “Inverter P.C. board”, Fin temperature for the chart of thermistor.
  • Page 49 10-5. TROUBLESHOOTING FLOW A How to check inverter/compressor Disconnect the connector between the compressor and the power module (IC700) (MUZ-GL09/12/15/18, MUY-GL09/12/15/18)/IGBT module (IC700) (MUZ- GL24, MUY-GL24). See 10-5. “Check of open phase”. Check the voltage between terminals. Replace the inverter P.C. board. Are the voltages balanced? Check the compressor.
  • Page 50 D Check of compressor winding ●Disconnect the connector between the compressor and the power module (IC700) (MUZ-GL09/12/15/18, MUY-GL09/12/15/18)/ IGBT module (IC700) (MUZ-GL24, MUY-GL24), 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 51 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 10-6.1.) board.
  • Page 52 H Check of R.V. coil (MUZ) MUZ-GL09/12/15/18NA MUZ-GL09/12/15/18NAH First of all, measure the resistance of R.V. coil to check if the coil is defective. Refer to 10-4. 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 53 I Check of outdoor fan motor Check the connection between the connector CN931 and CN932. Disconnect the connectors CN931 and CN932 from the inverter P.C. board. Is the resistance between each ter- minal of outdoor fan motor normal? (Refer to 10-4.) Disconnect CN932 from the inverter P.C.
  • Page 54 J Check of power supply Disconnect the connector between the compressor and the power module (IC700) (MUZ-GL09/12/15/18, MUY- GL09/12/15/18)/IGBT module (IC700) (MUZ-GL24, MUY-GL24). Rectify indoor/outdoor Turn ON power supply and press connecting wire. EMERGENCY OPERATION switch. Does the upper lamp of the Is there voltage 208/230 V AC Replace the indoor OPERATION INDICATOR lamp on...
  • Page 55 K Check of LEV (Expansion valve) MSZ-GL06/09/12/15NA MSZ-GL18NA MSZ-GL24NA MSY-GL09/12/15NA MSY-GL18NA MSY-GL24NA Turn ON the power supply. <Preparation of the remote controller> While pressing both OPERATION SELECT button and TOO COOL button on the remote controller at the same time, press RESET button. First, release RESET button.
  • Page 56 L Check of inverter P.C. board Check the outdoor fan motor. (Refer to 10-5. .) 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 57 M How to check miswiring and serial signal error MUZ-GL09/12/15NA Turn OFF the power supply. MUZ-GL09/12/15NAH Is there rated voltage in the power supply? Check the power supply. MUY-GL09/12/15NA Turn ON the power supply. Is there rated voltage between the outdoor terminal block S1 and S2? Check the wiring.
  • Page 58 MUZ-GL18/24NA MUZ-GL18/24NAH Turn OFF the power supply. MUY-GL18/24NA Is there rated voltage in the power supply? Check the power supply. Turn ON the power supply. Check the wiring. Is there rated voltage between outdoor terminal block S1 and S2? Press EMERGENCY OPERATION switch once. Does the OPERATION INDICATOR lamp light up? <Confirmation of the power to the indoor unit>...
  • Page 59 N Check of defrost heater (base pan heater) (MUZ-GL•NAH) MUZ-GL09/12/15/18/24NAH Check the following points before checking electric continuity. 1. Does the resistance of ambient temperature thermistor have the characteristics? Refer to 10-6.1. 2. Is the resistance of defrost heater normal? Refer to 10-4. 3.
  • Page 60 P Electromagnetic noise enters into TV sets or radios Is the unit grounded? Ground the unit. Is the distance between the antennas Extend the distance between the antennas and and the indoor unit within 9.91 ft. (3m), the indoor unit, and/or the antennas and the or is the distance between the antennas outdoor unit.
  • Page 61 10-6. TEST POINT DIAGRAM AND VOLTAGE 1. Inverter P.C. board MUZ-GL09NA - MUZ-GL12/15NA - MUZ-GL09NAH- MUZ-GL12/15NAH- MUY-GL09/12/15NA- Smoothing R.V.coil/21S4 Heater connector capacitor (C63) (CN721) (CN722) (MUZ) Smoothing Smoothing DB61 (MUZ-GL09/ Back side of unit capacitor (C61) 208/230 V AC capacitor (C62) 260 - 370 V DC 12/15NAH) Fuse (F701)
  • Page 62 MUZ-GL09/12/15NA - MUZ-GL09/12/15NAH - MUY-GL09/12/15NA- R.V.coil Smoothing Smoothing DB61 Back side of unit (CN721) capacitor (C62) capacitor (C61) 260 - 370 V DC 115 V AC Fuse (F801) Fuse (F701) 115 V AC T3.15AL250V T3.15AL250V Output to drive compressor (LDU, LDV, LDW) Fuse (F901)
  • Page 63 MUZ-GL18NA MUZ-GL18NAH R.V.coil/21S4 Smoothing MUY-GL18NA (CN721) capacitor (C63) Smoothing (MUZ) Smoothing capacitor Heater connector 208/230 V AC DB61 Back side of unit (CN722) capacitor (C62) (C61) 260 - 370 V DC (MUZ-GL18NAH) Fuse (F701) Fuse (F801) 208/230 V AC T3.15AL250V T3.15AL250V Fuse (F901) T3.15AL250V...
  • Page 64 MUZ-GL24NA MUZ-GL24NAH MUY-GL24NA Fuse (F601) T3.15AL250V R.V. coil/21S4 (CN602) 208/230 V AC (MUZ) Heater connector (CN601) (MUZ-GL24NAH) Signal of out- door fan motor (CN931) Expansion valve/LEV (CN724) Defrost thermistor /RT61 (CN671) (MUZ) Fuse (F901) Discharge temperature T3.15AL250V thermistor/RT62 (CN671) Output to Outdoor heat exchanger drive outdoor temperature thermistor...
  • Page 65 DISASSEMBLY INSTRUCTIONS <Detaching method of the terminals with locking mechanism> The terminal which has the locking mechanism can be detached as shown below. There are 2 types of the terminals with locking mechanism. The terminal without locking mechanism can be detached by pulling it out. Check the shape of the terminal before detaching.
  • Page 66 OPERATING PROCEDURE PHOTOS/FIGURES Screws of the Screw of the Photo 4 Photo 5 conduit cover conduit plate 2. Removing the inverter assembly, inverter P.C. board Photo 6 (1) Remove the cabinet and panels. (Refer to section 1.) (2) Disconnect the lead wire to the reactor and the following Screws of the heat sink *U2 model does not connectors:...
  • Page 67 OPERATING PROCEDURE PHOTOS/FIGURES 4. Removing the discharge temperature thermistor, Photo 8 Screw of the defrost thermistor, outdoor heat exchanger tempera- R.V. coil (MUZ) 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 con- nectors: <Inverter P.C.
  • Page 68 OPERATING PROCEDURE PHOTOS/FIGURES 5. Removing outdoor fan motor Photo 10 Screws of the outdoor fan motor (1) Remove the cabinet and panels. (Refer to section 1.) (2) Disconnect the following connectors: <Inverter P.C. board> CN931, CN932 (Fan motor) (3) Remove the propeller fan nut. (4) Remove the propeller fan.
  • Page 69 11-2. MUZ-GL18NA MUZ-GL18NAH MUY-GL18NA 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 70 OPERATING PROCEDURE PHOTOS/FIGURES 2. Removing the inverter assembly, inverter P.C. board Photo 5 Screws of the terminal (1) Remove the cabinet and panels. (Refer to section 1.) Screw of the heat sink block support and the (2) Disconnect the lead wire to the reactor and the following con- support and the separator back panel nectors:...
  • Page 71 OPERATING PROCEDURE PHOTOS/FIGURES 4. Removing the discharge temperature thermistor, Photo 8 Outdoor heat exchanger tempera- Ambient tem- defrost thermistor (MUZ), outdoor heat exchanger ture thermistor perature temperature thermistor and ambient temperature thermistor 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 72 11-3. MUZ-GL24NA MUZ-GL24NAH MUY-GL24NA 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 73 OPERATING PROCEDURE PHOTOS/FIGURES 2. Removing the inverter assembly, inverter P.C. board Photo 5 Screw of the relay panel and relay P.C. board Screws of the (1) Remove the cabinet and panels. (Refer to section 1.) P.B. support Inverter P.C. (2) Disconnect the lead wire to the reactor and the following con- Ground wires board nectors:...
  • Page 74 OPERATING PROCEDURE PHOTOS/FIGURES 4. Removing the discharge temperature thermistor, Photo 7 Ambient temperature defrost thermistor (MUZ), outdoor heat exchanger Outdoor heat exchanger thermistor temperature thermistor and ambient temperature temperature thermistor 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 75 OBH733G...
  • Page 76 HEAD OFFICE: TOKYO BUILDING, 2-7-3, MARUNOUCHI, CHIYODA-KU, TOKYO 100-8310, JAPAN © Copyright 2015 MITSUBISHI ELECTRIC CORPORATION Issued: Apr. 2019. No. OBH733 REVISED EDITION-G Issued: Nov. 2018. No. OBH733 REVISED EDITION-F Issued: Jul. 2017. No. OBH733 REVISED EDITION-E Issued: Mar. 2017. No. OBH733 REVISED EDITION-D Issued: Sep.

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