Mitsubishi Electric NTXSMT09A112AA Service Manual
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Mitsubishi Electric NTXSMT09A112AA Service Manual

Mitsubishi Electric NTXSMT09A112AA Service Manual

Outdoor unit, hfc utilized r410a, indoor unit
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OUTDOOR UNIT
SERVICE MANUAL
Models
NTXSMT09A112AA
NTXSMT12A112AA
NTXSMT15A112AA
NTXSMT18A112AA
NTXSMT24A112AA
NTXSMT24A112AA
Revision B:
• Some descriptions have been modified.
OBHT747 REVISED EDITION-A is void.
HFC
utilized
R410A
NTXSMT09A112AB
NTXSMT12A112AB
NTXSMT15A112AB
NTXSMT18A112AB
Indoor unit service manual
NTXWMT•A112AA Series (OBHT746)
CONTENTS
1. TECHNICAL CHANGES ······························3
2. PART NAMES AND FUNCTIONS ··················4
3. SPECIFICATION ········································5
4. OUTLINES AND DIMENSIONS ··················· 10
5. WIRING DIAGRAM ··································· 12
6. REFRIGERANT SYSTEM DIAGRAM ··········· 15
7. DATA ······················································ 18
8. ACTUATOR CONTROL ····························· 31
9. SERVICE FUNCTIONS ······························ 32
10. TROUBLESHOOTING ······························· 33
11. DISASSEMBLY INSTRUCTIONS ················· 58
PARTS CATALOG (OBBT747)
No. OBHT747
REVISED EDITION-B

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Summary of Contents for Mitsubishi Electric NTXSMT09A112AA

  • Page 1: Table Of Contents

    Revision B: • Some descriptions have been modified. OBHT747 REVISED EDITION-A is void. OUTDOOR UNIT No. OBHT747 utilized REVISED EDITION-B R410A SERVICE MANUAL Models NTXSMT09A112AA NTXSMT09A112AB NTXSMT12A112AA NTXSMT12A112AB NTXSMT15A112AA NTXSMT15A112AB NTXSMT18A112AA NTXSMT18A112AB NTXSMT24A112AA Indoor unit service manual NTXWMT•A112AA Series (OBHT746) CONTENTS 1.
  • 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 NTXSMT09A112AA NTXSMT12A112AA NTXSMT15A112AA NTXSMT18A112AA NTXSMT24A112AA 1. New model NTXSMT09A112AA NTXSMT09A112AB NTXSMT12A112AA NTXSMT12A112AB 1. Fan motor has been changed. 2. Inverter P.C. board has been changed. 3. R.V. coil has been changed. 4. LEV has been changed. 5. Outdoor heat exchanger has been changed.

  • Page 4: Part Names And Functions

    PART NAMES AND FUNCTIONS NTXSMT09A112AA NTXSMT12A112AA NTXSMT15A112AA NTXSMT18A112AA NTXSMT09A112AB NTXSMT12A112AB NTXSMT15A112AB NTXSMT18A112AB Air inlet (back and side) Piping Air outlet Drain hose Drain outlet NTXSMT24A112AA Air inlet (back and side) Piping Drain hose Air outlet Drain outlet OBHT747B...

  • Page 5: Specification

    SPECIFICATION Outdoor unit model NTXSMT09A112AA NTXSMT09A112AB Btu/h 9,000 ( 3,800 ~ 10,000 ) Cooling 1 Capacity Rated (Minimum~Maximum) Btu/h 10,900 ( 4,500 ~ 11,800 ) Heating 47 1 Capacity Btu/h 6,700 (7,200) Heating 17 2 Rated (Maximum) 750 (240 - 850)
  • Page 6 Outdoor unit model NTXSMT12A112AA NTXSMT12A112AB Btu/h 12,000 ( 3,800 ~ 12,200 ) Cooling 1 Capacity Rated (Minimum~Maximum) Btu/h 12,200 ( 4,500 ~ 14,500 ) Heating 47 1 Capacity Btu/h 7,600 (9,000) Heating 17 2 Rated (Maximum) 1,210 (240 - 1,300) Cooling 1 Power consumption Rated (Minimum~Maximum)
  • Page 7 NTXSMT15A112AA NTXSMT18A112AA Outdoor unit model NTXSMT15A112AB NTXSMT18A112AB Btu/h 14,000 (3,100 - 16,000) 17,200 (5,800 - 18,000) Cooling 1 Capacity Rated (Minimum~Maximum) Btu/h 18,000 (4,800 - 18,500) 18,000 (5,400 - 20,900) Heating 47 1 Capacity Btu/h 11,500 (14,000) 11,500 (15,000) Heating 17 2 Rated (Maximum) 1,127 (187 - 1,957) 1,598 (308 - 2,028)
  • Page 8 Outdoor unit model NTXSMT24A112AA Cooling 1 Btu/h 22,500 (5,800 ~ 22,500) Capacity Rated (Minimum~Maximum) Heating 47 1 Btu/h 26,000 (5,400 ~ 26,000) Capacity Heating 17 2 Btu/h 18,500 (18,500) Rated (Maximum) Cooling 1 2,575 (275 ~ 2,575) Power consumption Rated (Minimum~Maximum) Heating 47 1 2,445 (265 ~ 2,445) Power consumption...

  • Page 9: Operation

    3-1. 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 10: Outlines And Dimensions

    OUTLINES AND DIMENSIONS Unit: inch NTXSMT09A112AA NTXSMT12A112AA NTXSMT15A112AA NTXSMT18A112AA NTXSMT09A112AB NTXSMT12A112AB NTXSMT15A112AB NTXSMT18A112AB REQUIRED SPACE 4 in. (100 mm) or more when front and sides of the unit are clear When any 2 sides of left, right and rear of the unit are clear...
  • Page 11 Unit: inch NTXSMT24A112AA 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 12: Wiring Diagram

    WIRING DIAGRAM NTXSMT09A112AA NTXSMT12A112AA NTXSMT09A112AB NTXSMT12A112AB OBHT747B...
  • Page 13 NTXSMT15A112AA NTXSMT18A112AA NTXSMT15A112AB NTXSMT18A112AB OBHT747B...
  • Page 14 NTXSMT24A112AA OBHT747B...

  • Page 15: Refrigerant System Diagram

    REFRIGERANT SYSTEM DIAGRAM NTXSMT09A112AA NTXSMT12A112AA Unit: Inch (mm) NTXSMT09A112AB NTXSMT12A112AB Refrigerant pipe ø3/8 (ø9.52) 4-way valve (with heat insulator) Muffler Outdoor heat exchanger Stop valve temperature (with service port) thermistor Outdoor Muffler Discharge RT68 heat Flared connection temperature exchanger thermistor...
  • Page 16 Unit: Inch (mm) NTXSMT24A112AA Muffler 4-way with #100 mesh strainer Refrigerant pipe ø5/8 ( ø 15.88) valve (with heat insulator) Service port Stop valve (with service port) Outdoor Flared connection Discharge heat Defrost temperature exchanger Service thermistor thermistor port RT62 RT61 Compressor Outdoor heat...

  • Page 17: Additional Refrigerant Charge (R410A: Oz.)

    MAX. REFRIGERANT PIPING LENGTH and MAX. HEIGHT DIFFERENCE Refrigerant piping: ft. Piping size O.D: in. Model Max. Length Max. Height difference Liquid NTXSMT09A112AA NTXSMT09A112AB NTXSMT12A112AA NTXSMT12A112AB NTXSMT15A112AA NTXSMT15A112AB NTXSMT18A112AA NTXSMT18A112AB NTXSMT24A112AA Indoor unit Max. Height difference Max. Length Outdoor unit ADDITIONAL REFRIGERANT CHARGE (R410A: oz.)

  • Page 18: Data

    DATA NTXSMT09A112AA NTXSMT12A112AA NTXSMT15A112AA NTXSMT18A112AA NTXSMT09A112AB NTXSMT12A112AB NTXSMT15A112AB NTXSMT18A112AB NTXSMT24A112AA 7-1. PERFORMANCE DATA 1) COOLING CAPACITY Indoor air Outdoor intake air DB temperature (˚F) Model IWB (˚F) SHC TPC SHC TPC SHC TPC SHC TPC SHC TPC 11.0 0.67 10.3 0.73...

  • Page 19: Heating Capacity

    3) HEATING CAPACITY CORRECTIONS Refrigerant piping length (one way: ft.) Model 25 (std.) NTXSMT09A112AA NTXSMT09A112AB NTXSMT12A112AA NTXSMT12A112AB 0.997 0.993 — NTXSMT15A112AA NTXSMT15A112AB NTXSMT18A112AA NTXSMT18A112AB 0.997 0.993 0.987 NTXSMT24A112AA 4) HEATING CAPACITY Indoor air Outdoor intake air WB temperature (˚F) Model IDB (˚F)

  • Page 20: Performance Curve

    7-2. PERFORMANCE CURVE Cooling Cooling capacity (at Rated frequency) Indoor intake air Wet-bulb temperature( F) Outdoor intake air DB temperature(°F) NTXSMT09A112AA NTXSMT12A112AA NTXSMT09A112AB NTXSMT12A112AB SHF at rating condition = 0.82 SHF at rating condition = 0.77 = 399 CFM Airflow...
  • Page 21 Heating Heating capacity (at Rated frequency) Outdoor intake air WB temperature (°F) NTXSMT09A112AA NTXSMT12A112AA NTXSMT09A112AB NTXSMT12A112AB = 406 CFM = 406 CFM Airflow Airflow Outdoor intake air WB temperature (°F) Outdoor intake air WB temperature (°F) NTXSMT15A112AA NTXSMT18A112AA NTXSMT15A112AB NTXSMT18A112AB...
  • Page 22 7-3. CONDENSING PRESSURE Cooling Data are based on the condition of indoor humidity 50 %. Airflow should be set to High speed. NTXSMT09A112AA NTXSMT09A112AB (PSIG) (PSIG) 100 105 (°F) Outdoor ambient temperature Outdoor ambient temperature NTXSMT12A112AA NTXSMT12A112AB (PSIG) (PSIG) Outdoor ambient temperature...
  • Page 23 NTXSMT15A112AA NTXSMT15A112AB (PSIG) (PSIG) (°F) 100 105 100 105 (°F) Outdoor ambient temperature Outdoor ambient temperature NTXSMT18A112AA NTXSMT18A112AB (PSIG) (PSIG) 100 105 (°F) (°F) 100 105 Outdoor ambient temperature Outdoor ambient temperature NTXSMT24A112AA (PSIG) (PSIG) (°F) (°F) Outdoor ambient temperature Outdoor ambient temperature Heating Data are based on the condition of outdoor humidity 75%.
  • Page 24 NTXSMT09A112AA NTXSMT12A112AA NTXSMT09A112AB NTXSMT12A112AB (PSIG) (PSIG) 58Hz 58Hz 75 (°F) 75 (°F) Outdoor ambient temperature Outdoor ambient temperature NTXSMT15A112AA NTXSMT15A112AB (PSIG) (PSIG) 58Hz 58Hz (°F) (°F) Outdoor ambient temperature Outdoor ambient temperature OBHT747B...
  • Page 25 NTXSMT18A112AA NTXSMT18A112AB (PSIG) (PSIG) 58Hz 58Hz (°F) (°F) Outdoor ambient temperature Outdoor ambient temperature NTXSMT24A112AA (PSIG) (PSIG) 81Hz 81Hz (°F) (°F) Outdoor ambient temperature Outdoor ambient temperature OBHT747B...

  • Page 26: Standard Operation Data

    Power supply phase, 208/230, 1, 60 208/230, 1, 60 Input 0.022 0.023 0.022 0.023 Fan motor current 0.24/0.22 0.25/0.23 0.24/0.22 0.25/0.23 NTXSMT09A112AA NTXSMT12A112AA Outdoor unit NTXSMT09A112AB NTXSMT12A112AB Power supply phase, 208/230, 1, 60 208/230, 1, 60 Input 0.728 0.877 1.188 0.967 Comp.
  • Page 27 7-4. STANDARD OPERATION DATA NTXWMT15A112AA NTXWMT18A112AA Model NTXWMT15A112AB NTXWMT18A112AB Item Unit Cooling Heating Cooling Heating Capacity Btu/h 14,000 18,000 17,200 18,000 — 0.78 — 0.86 — Input 1.17 1.60 1.64 1.59 Rated frequency 56.5 NTXWMT15A112AA NTXWMT18A112AA Indoor unit NTXWMT15A112AB NTXWMT18A112AB Power supply phase, 208/230, 1, 60...
  • Page 28 7-4. STANDARD OPERATION DATA Model NTXWMT24A112AA Item Unit Cooling Heating Capacity Btu/h 22,500 26,000 — 0.89 — Input 2.63 Rated frequency Indoor unit NTXWMT24A112AA Power supply phase, 208/230, 1, 60 Input 0.055 Fan motor current 0.55/0.50 Outdoor unit NTXSMT24A112AA Power supply phase, 208/230, 1, 60 Input...
  • Page 29 7-5. CAPACITY AND INPUT CORRECTION BY INVERTER OUTPUT FREQUENCY NTXSMT09A112AA NTXSMT09A112AB Correction of Cooling capacity Correction of Cooling total input Correction of Heating total input Correction of Heating capacity The operational frequency of compressor The operational frequency of compressor The operational frequency of compressor...
  • Page 30 NTXSMT15A112AA NTXSMT15A112AB 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 NTXSMT18A112AA NTXSMT18A112AB Correction of Heating total input...

  • Page 31: Actuator Control

    ACTUATOR CONTROL NTXSMT09A112AA NTXSMT12A112AA NTXSMT15A112AA NTXSMT18A112AA NTXSMT09A112AB NTXSMT12A112AB NTXSMT15A112AB NTXSMT18A112AB NTXSMT24A112AA 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 32: Service Functions

    SERVICE FUNCTIONS NTXSMT09A112AA NTXSMT12A112AA NTXSMT15A112AA NTXSMT18A112AA NTXSMT09A112AB NTXSMT12A112AB NTXSMT15A112AB NTXSMT18A112AB NTXSMT24A112AA 9-1. 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 10-6.1.).

  • Page 33: Troubleshooting

    TROUBLESHOOTING NTXSMT09A112AA NTXSMT12A112AA NTXSMT15A112AA NTXSMT18A112AA NTXSMT09A112AB NTXSMT12A112AB NTXSMT15A112AB NTXSMT18A112AB NTXSMT24A112AA 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. 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, then after con- firming the horizontal vane is closed, turn off the breaker and/or disconnect the power plug.
  • Page 34 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 35 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 36 3. Table of outdoor unit failure mode recall function NOTE: Blinking patterns of this mode differ from the ones of TROUBLESHOOTING CHECK TABLE (10-3.). NTXSMT09A112AA NTXSMT09A112AB NTXSMT12A112AA NTXSMT12A112AB OPERATION Indoor/ Outdoor unit INDICATOR Abnormal point LED indication outdoor unit Condition...
  • Page 37 NOTE: Blinking patterns of this mode differ from the ones of TROUBLESHOOTING CHECK TABLE (10-3.). OPERATION Indoor/ Outdoor unit INDICATOR Abnormal point LED indication outdoor unit Condition Remedy failure mode upper lamp (Failure mode / protection) (Outdoor P.C. board) failure mode recall function (Indoor unit) recall function...

  • Page 38: Operation

    NTXSMT15A112AA NTXSMT15A112AB NTXSMT18A112AA NTXSMT18A112AB NOTE: Blinking patterns of this mode differ from the ones of TROUBLESHOOTING CHECK TABLE (10-3.). NTXSMT24A112AA 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.
  • Page 39 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 40 10-3. TROUBLESHOOTING CHECK TABLE Abnormal point/ Symptom LED indication Condition Remedy Condition Outdoor unit 1-time blink every Outdoor power Overcurrent protection cut-out operates 3 consecutive times • Reconnect connector of does not 2.5 seconds system within 1 minute after the compressor gets started. compressor.
  • Page 41 Abnormal point/ Symptom LED indication Condition Remedy Condition Outdoor unit 1-time blink Frequency drop by Current from power outlet is nearing Max. fuse size. The unit is normal, but check the operates. 2.5 seconds OFF current protection following. • Check if indoor filters are clogged. •...

  • Page 42: Trouble Criterion Of Main Parts

    10-4. TROUBLE CRITERION OF MAIN PARTS NTXSMT09A112AA NTXSMT12A112AA NTXSMT15A112AA NTXSMT18A112AA NTXSMT09A112AB NTXSMT12A112AB NTXSMT15A112AB NTXSMT18A112AB NTXSMT24A112AA Part name Check method and criterion Figure Measure the resistance with a multimeter. Defrost thermistor (RT61) Refer to 10-6. “TEST POINT DIAGRAM AND VOLTAGE”, 1. “Inverter Fin temperature P.C.
  • Page 43 10-5. 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 10-5. “Check of open phase”. Replace the inverter P.C. board. Are the voltages balanced? Check the compressor. See 10-5.
  • Page 44 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 45 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 46 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 termi- nal of outdoor fan motor normal? (Refer to 10-4.) Disconnect CN932 from the inverter P.C.
  • Page 47 J Check of power supply Disconnect the connector between the compressor and the power module (IC700) 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 between the indoor terminal...
  • Page 48 K Check of LEV (Expansion valve) 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. Hold down the other 2 buttons for another 3 seconds.

  • Page 49: Emergency Operation

    L Check of inverter P.C. board Check the outdoor fan motor. (Refer to 10-5. .) Is the fuse (F901) blown on the inverter 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 50 M How to check miswiring and serial signal error NTXSMT09/12A112AA Turn OFF the power supply. NTXSMT09/12A112AB Is there rated voltage in the power supply? Check the power supply. Turn ON the power supply. Is there rated voltage between outdoor terminal block S1 and S2? Check the wiring.
  • Page 51 Turn OFF the power supply. NTXSMT15/18/24A112AA NOTE: Refer to the indoor unit service manual. NTXSMT15/18A112AB Is there rated voltage in the power supply? Check the power supply. Turn ON the power supply. Is there rated voltage between outdoor terminal block S1 and S2? Check the wiring.
  • Page 52 N Check of defrost heater (Optional parts) 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 53 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 54 10-6. TEST POINT DIAGRAM AND VOLTAGE 1. Inverter P.C. board NTXSMT09A112AA NTXSMT12A112AA R.V.coil/21S4 (CN721) Smoothing Smoothing DB61 Back side of unit 208/230 V AC capacitor (C62) capacitor (C61) 260 - 370 V DC Fuse (F701) Fuse (F801) 208/230 V AC T3.15AL250V...
  • Page 55 1. Inverter P.C. board NTXSMT15A112AA NTXSMT18A112AA Smoothing capacitor (C63) Smoothing DB61 Back side of unit Smoothing R.V.coil/21S4 capacitor (C62) 260 - 370 V DC capacitor (C61) (CN721) 208/230 V AC Fuse (F701) Fuse (F801) 208/230 V AC T3.15AL250V T3.15AL250V Fuse (F901) T3.15AL250V Output to drive outdoor...
  • Page 56 1. Inverter P.C. board NTXSMT09A112AB NTXSMT12A112AB NTXSMT15A112AB NTXSMT18A112AB Smoothing DB61 Smoothing Back side of unit R.V.coil (CN721) capacitor (C61) 260 - 370 V DC capacitor (C63) *1 208/230 V AC Smoothing Fuse (F801) Fuse (F701) 208/230 V AC capacitor (C62) T3.15AL250V T3.15AL250V Output to...
  • Page 57 1. Inverter P.C. board NTXSMT24A112AA Smoothing R.V.coil/21S4 capacitor (C63) (CN721) Smoothing Smoothing Back side of unit DB61 Heater connector 208/230 V AC capacitor (C62) capacitor (C61) 260 - 370 V DC (CN722) (Optional parts) Fuse (F701) Fuse (F801) 208/230 V AC T3.15AL250V T3.15AL250V Fuse (F901)

  • Page 58: Disassembly Instructions

    Locking lever lever. Connector 11-1. NTXSMT09A112AA NTXSMT12A112AA NTXSMT15A112AA NTXSMT18A112AA NTXSMT09A112AB NTXSMT12A112AB NTXSMT15A112AB NTXSMT18A112AB : Indicates the visible parts in the photos/figures. NOTE: Turn OFF the power supply before disassembly. : Indicates the invisible parts in the photos/figures.
  • Page 59 OPERATING PROCEDURE PHOTOS/FIGURES Photo 4 Photo 5 Screws of the Screw of the conduit cover conduit plate 2. Removing the inverter assembly, inverter P.C. board Photo 6 NTXSMT09/12/15/18A112AA (1) Remove the cabinet and panels. (Refer to section 1.) Screws of the heat sink support and the separator (2) Disconnect the lead wire to the reactor and the following connectors: <Inverter P.C.
  • Page 60 OPERATING PROCEDURE PHOTOS/FIGURES 3. Removing R.V. coil Photo 8 NTXSMT09/12/15/18A112AA (1) Remove the cabinet and panels. (Refer to section 1.) Screw of the (2) Disconnect the following connectors: Heat sink Heat sink support Terminal block <Inverter P.C. board> support P.C. board CN721 (R.V.
  • Page 61 OPERATING PROCEDURE PHOTOS/FIGURES 4. Removing the discharge temperature thermistor, Photo 10 defrost thermistor, outdoor heat exchanger tempera- 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 62 OPERATING PROCEDURE PHOTOS/FIGURES 5. Removing outdoor fan motor Photo 14 (1) Remove the cabinet and panels. (Refer to section 1.) Screws of the outdoor fan motor (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 63 11-2. NTXSMT24A112AA NOTE: Turn OFF the power supply before disassembly. OPERATING PROCEDURE PHOTOS/FIGURES 1. Removing the cabinet Photo 1 Screws of the top panel (1) Remove the screws of the service panel. (2) Remove the screws of the top panel. (3) Remove the screw of the valve cover.
  • Page 64 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 support and the separator back panel connectors:...
  • Page 65 OPERATING PROCEDURE PHOTOS/FIGURES 4. Removing the discharge temperature thermistor, Outdoor heat Photo 8 exchanger tempera- defrost thermistor, outdoor heat exchanger tempera- Ambient ture thermistor temperature ture 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 66 MITSUBISHI ELECTRIC TRANE HVAC US LLC HEAD OFFICE: 1340 SATELLITE BOULEVARD, SUWANEE, GA 30024, USA © Copyright 2018 MITSUBISHI ELECTRIC CORPORATION Issued: Mar. 2022. No. OBHT747 REVISED EDITION-B Issued: Sep. 2019. No. OBHT747 REVISED EDITION-A Published: Dec. 2018. No. OBHT747 Specifications are subject to change without notice.

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