Midea MCH2U-18PHH2 Service Manual
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Midea MCH2U-18PHH2 Service Manual

Multi outdoor/ condensing units multi zone
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CONDENSING UNITS
Revision C:
Model Numbers:
MCH2U-18PHH2
MCH5U-48PHH2

Table of Contents

1.
2.
Suggested Indoor Unit Model Numbers
3.
4.
5.
6.
7.
8.
9.
WARNING
Installation MUST conform with local building codes or, in the absence of local
codes, with the National Electrical Code NFPA70/ANSI C1-1993 or current edition
and Canadian Electrical Code Part1 CSA C.22.1.
The information contained in the manual is intended for use by a qualified service
technician familiar with safety procedures and equipped with the proper tools and
test instruments
Installation or repairs made by unqualified persons can result in hazards to you
and others.
Failure to carefully read and follow all instructions in this manual can result in
equipment malfunction, property damage, personal injury and/or death.
MULTI OUTDOOR UNITS
SERVICE MANUAL
ODMI-E-1606
MCH3U-27PHH2 MCH4U-36PHH2
1
Multi zone

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Summary of Contents for Midea MCH2U-18PHH2

  • Page 1: Table Of Contents

    MULTI OUTDOOR UNITS Multi zone SERVICE MANUAL CONDENSING UNITS Revision C: ODMI-E-1606 Model Numbers: MCH2U-18PHH2 MCH3U-27PHH2 MCH4U-36PHH2 MCH5U-48PHH2 Table of Contents Indoor Unit Combination Suggested Indoor Unit Model Numbers Dimension Of Outdoor Unit Refrigerant Cycle Diagram Installation Details Electronic Function...
  • Page 2 8.2 Indoor Unit Error Display ..........................34 8.3 Outdoor Unit Display ..........................37 8.4 Diagnosis and Solution ..........................42 8.5 Trouble Criterion Of Main Parts........................91 Disassembly Instructions ..........................103  MCH2U-18PHH2 (WCA30 metal plate) ....................103  MCH3U-27PHH2 (WD30 metal plate) ....................110...
  • Page 3  MCH4U-36PHH2 (WD30 metal plate) ....................118  MCH5U-48PHH2 (WE30 metal plate) ....................125...

  • Page 4: Indoor Unit Combination

    1. Indoor Unit Combination Multi DC Nominal Suggested Outdoor Limit capacity Combination Unit 1drive 2 5.2kW None 9+12 12+12 Multi DC Nominal Suggested Outdoor Limit capacity Combination Multi DC Unit Nominal Suggested Outdoor Limit capacity Combination Unit 9+12 9+18 9+18 12+12 12+12 12+18...
  • Page 5 9+9+12+18 9+9+12+24 9+9+18+18 9+9+18+24 9+12+12+12 9+12+12+18 9+12+12+24 9+12+18+18 9+18+18+18 12+12+12+12 12+12+12+18 12+12+12+24 12+12+18+18 9+9+9+9+9 9+9+9+9+12 9+9+9+9+18 9+9+9+9+24 9+9+9+12+12 9+9+9+12+18 9+9+9+18+18 9+9+12+12+12 9+9+12+12+18 9+12+12+12+12 9+12+12+12+18 12+12+12+12+12...

  • Page 6: Dimension Of Outdoor Unit

    2. Dimension Of Outdoor Unit Model Unit： MCH2U-18PHH2 33.3 14.3 27.6 36.0 21.3 13.8 inch 1034 MCH3U-27PHH2 inch 37.2 16.5 31.9 40.6 26.5 15.9 1034 MCH4U-36PHH2 inch 37.2 16.5 31.9 40.6 26.5 15.9 1333 1060 MCH5U-48PHH2 inch 37.5 16.3 52.5 41.7...

  • Page 7: Refrigerant Cycle Diagram

    3. Refrigerant Cycle Diagram 3.1 Refrigeration circuit drawing of inverter 1 drive 2 type INDOOR OUTDOOR EXV A CAPILIARY A LIQUID VALVE A CHECK VALVE EXV B CAPILIARY B LIQUID VALVE B Condenser temp. sensor CAPILIARY TUBE HEAT HEAT EXCHANGE T4 Ambient T1 Room EXCHANGE...
  • Page 8 3.3 Refrigeration circuit drawing of inverter 1 drive 4 type INDOOR OUTDOOR EXV A CAPILIARY A LIQUID VALVE A EXV B CAPILIARY B LIQUID VALVE B CHECK VALVE EXV C CAPILIARY C LIQUID VALVE C Condenser temp. sensor EXV D CAPILIARY D CAPILIARY TUBE LIQUID VALVE D HEAT...
  • Page 9 INDOOR OUTDOOR EXV A CAPILIARY A LIQUID VALVE A EXV B CAPILIARY B LIQUID VALVE B EXV C CAPILIARY C CHECK VALVE LIQUID VALVE C EXV D CAPILIARY D LIQUID VALVE D Condenser temp. sensor CAPILIARY TUBE EXV E CAPILIARY E LIQUID VALVE E HEAT EXCHANGE...

  • Page 10: Installation Details

    Additional refrigerant charge 4. Installation Details 1 drive 1 drive 1 drive 1 drive 4.1 Wrench torque sheet for Pre-charge 22.5 37.5 installation pipe length (98.4ft) (49.2ft) (73.8ft) (123ft) Additio 15 x 15 x 15 x 15 x Outside Additional (length (length (length...

  • Page 11: First-Time Installation

    4.4 First-Time Installation pin of the Handle Lo to the 3-way valve gas service port. 3. Connect the charge hose of the Handle Air and moisture in the refrigerant system Hi to the vacuum pump. cause the following problems: 4. Fully open the Handle Lo of the manifold valve.

  • Page 12: Adding Refrigerant After Long-Term System Operation

    1) Connect the charge hose to the charging 1) Connect the charge hose to the 3-way cylinder and open the 2-way and 3-way service port and open the 2-way and 3-way valves. valve. With the charge hose you disconnected Connect the charge hose to the valve at the from the vacuum pump, connect it to the bottom of the cylinder.
  • Page 13 Procedure 1). Confirm that both the 2-way and 3-way valves are set to the opened position 1) Completely tighten the flare nuts of the Remove the valve stem caps and confirm that indoor and outdoor units, confirm that the valve stems are in the opened position. both the 2-way and 3-way valves are set Be sure to use a hexagonal wrench to operate to the closed position.

  • Page 14: Evacuation After Servicing The Outdoor Unit Refrigeration Circuit

    pressure indicator is a little higher than the atmosphere pressure. Then remove the charge hose from the 3 way valve. 8) Fully open the 2 way valve and 3 way valve and securely tighten the cap of the 3 way valve. 4.7 Evacuation after servicing the outdoor unit refrigeration circuit Procedure:...

  • Page 15: Electronic Function

    refrigerant system. 6. Electronic Function For MCH3U-27PHH2/MCH4U- 6.1 Abbreviation 36PHH2/MCH5U-48PHH2 There are one low-pressure centralized valve T1: Indoor ambient temperature and one high-pressure centralized valve, it will be more time saving when vacuum and T2: Middle indoor heat exchanger coil recycle refrigerant.
  • Page 16 The temperature interval for the current limit ----If the temperature increase and T5≧110℃ is the same as the range of the T4 ℉), decrease the frequency to a lower (230 frequency limit. level every 2 minutes till to F1. Cooling mode: ℉) for 10 seconds, the ---If T5≧115℃...

  • Page 17: Control And Functions

    6.3.9 Outdoor Unit Anti-Freezing Protection ℃ When T2<4℃ for 250seconds or T2<0℃, the indoor unit capacity demand is zero and HeatT4Zone4I resumes normal operation when T2>8℃ and the protection time is no less than 3 HeatT4Zone3I minutes. HeatT4Zone2I 6.3.10 Oil Return HeatT4Zone1I Rules for Operation 1.

  • Page 18: Heating Mode

    temperature T1 Ts ℃ Fmax= T4FREMAXC0 51.5 50.5 Fmax= T4FREMAXC1 45.5 44.5 Fmax= T4FREMAXC2 Fmax= T4FREMAXC3 Capacity area Fmax= T4FREMAXC4 Norm code 2 1.5 1 0.5 0 Fmax= T4FREMAXC5 Fmax= T4FREMAXC6 Model Fmax= T4FREMAXC7 Fmax= T4FREMAXC8 Note: The final result is an integer. Fmax= T4FREMAXC9 Use the following table and final capacity request to confirm the operating...
  • Page 19 Then modify it according to a T2 average (correction): ℃ Note:Average value of T2：Sum T2 value of all indoor units)/ (indoor units number Standby ℃ T2 average Fmax=T4FREHEATMAX1 Decrease frequency Fmax=T4FREHEATMAX2 Fmax=T4FREHEATMAX3 Keep frequency Fmax=T4FREHEATMAX4 Increase frequency Fmax=T4FREHEATMAX5 Fmax=T4FREHEATMAX6 Fmax=T4FREHEATMAX7 Fmax=T4FREHEATMAX8 Use the following table and final capacity request...
  • Page 20 2) If the compressor cumulative running time reaches 35 minutes and T3< TCDI2 6.4.3 Outdoor Fan Control and T3＋T30SUBT3TWO≦T30. 6.4.3.1 Cooling Mode 3) If the compressor cumulative running time reaches 40 minutes and T3< -24C for 3 Under normal operating conditions, the minutes.
  • Page 21 Outdoor temperature℃ Exit low ambient cooling mode run with high fan for 1 minute Breeze fan speed Supper low fan speed Low fan speed Middle fan speed High fan speed Increase fan speed increase LowCoolT3_ON Supper high fan speed Keep current fan speed LowCoolT3_Down Decrease fan speed LowCoolT3_OFF...
  • Page 22 average, the outdoor gives the following In other modes, a four-way valve is closed. modification commands: When the unit is switched from heating to other modes, the four-way valve turns off ---- If the T2B＞average, the relevant valve after the compressor has been off for 2 needs to open 16p more consecutive minutes.

  • Page 23: Wiring Diagrams

    7. Wiring Diagrams 7.1 Wiring diagram of 1 drive 2 outdoor MCH2U-18PHH2...
  • Page 24 7.2 Wiring diagram of 1 drive 3 outdoor MCH3U-27PHH2...
  • Page 25 7.3 Wiring diagram of 1 drive 4 outdoor MCH4U-36PHH2...
  • Page 26 7.4 Wiring diagram of MCH5U-48PHH2...
  • Page 27 PCB board of MCH2U-18PHH2, MCH3U-27PHH2 LED1 status light, by which you can judge the unit Normal or Error (standby) Flashing once per second(low speed flashing) (error) Flashing once per half second (high speed flashing) (running) aways on CN21 Low VOL supply...
  • Page 28 IPM board of MCH2U-18PHH2, MCH3U-27PHH2 CN4(L)-CN5(N) power supply connect to the main board no use fuse1 T/3.15A 17122000018251 CN11 F US E1 T /3 .15A 250 VAC CAUTION HIGH VOLTAGE PTC1 ZR3 ZR2 PTC2 R11_1 R10_1 J 7 J6 CN_Reactor...
  • Page 29 PCB board of MCH4U-36PHH2 Connect to the Indoor evap.pipe out temp. sensor T2B-A、T2B-B、T2B-C、T2B-D、T2B-E external drive DC fan 6 5 4 3 2 1 motor connector Electric Expansion Electric Expansion Electric Expansion testPort Electric Expansion Electric Expansion external drive DC fan Value C external drive DC fan Value E...
  • Page 30 IPM board of MCH4U-36PHH2 connect to DC fan motor TO MAIN 0VAC (standby) CN19 CN55 10-200VAC (running) EU-KFR105W/BP2T3N1-350(767).D.13.MP2-1 202302141237 IC17 IC11 R114 R107 IC12 IPM2 R111 IC16 CN57 R174 C103 C102 R144 R147 R182 R179 C101 CN57 R184 C106 R180 C105 Debug R104...
  • Page 31 PCB board of MCH5U-48PHH2...
  • Page 32 IPM board of MCH5U-48PHH2...

  • Page 33: Troubleshooting

    8. Troubleshooting 8.1Safety Electricity is stored in capacitors, even when the power supply is shut off. Do not forget to discharge the electricity in the capacitors. The value of resistance is about 1500 ohm to 2000 ohm Electrolytic Capacitors (HIGH VOLTAGE! CAUTION!) Bulb (25-40W) The voltage in P3 and P4 in outdoor PCB is high voltage about 310V The voltage in P5 and P6 in outdoor PCB is high voltage about 310V...

  • Page 34: Indoor Unit Error Display

    8.2 Indoor Unit Error Display For Old Console series Operation Timer Failure frost ★ Indoor room temperature sensor (T1 ) malfunction ★ Evaporator coil temperature sensor (T2) malfunction ★ Communication malfunction between indoor and outdoor units  ★ Low ambient temperature cut off in heating ★...
  • Page 35 Outdoor temperature sensor(coil sensor T3 or ambient temperature ★  E0,E4 sensor T4) malfunction or Outdoor unit EEPROM parameter error ★  ★ Outdoor fan speed malfunction ★   Indoor fan speed malfunction —— Over-voltage or under-voltage ★  ...
  • Page 36 ★ 6 times ★ —— Indoor units mode conflict ★ flash ,  light, X extinguished Outdoor unit error display MCH2U-18PHH2, MCH3U-27PHH2, MCH4U-36PHH2, MCH5U-48PHH2; New indoor Display LED STATUS Error Outdoor unit EEPROM parameter error Communication malfunction between indoor and outdoor units Communication malfunction between IPM board and outdoor main ——...

  • Page 37: Outdoor Unit Display

    Over-voltage or under-voltage protection —— PFC module protection Outdoor fan speed malfunction —— No. A Indoor unit coil outlet temp. sensor malfunction —— No. B Indoor unit coil outlet temp. sensor malfunction —— No. C Indoor unit coil outlet temp. sensor malfunction ——...
  • Page 38 Display Remark Number Presses Normal display Displays running frequency, running state, or malfunction code Quantity of indoor units with working Actual data connection Display Number of indoor unit Outdoor unit running mode code Off: 0,Fan only: 1, Cooling: 2, Heating: 3, Forced cooling: 4. Forced defrost:A Indoor unit A capacity Indoor unit B capacity...
  • Page 39 Indoor unit D capacity demand code Indoor unit E capacity demand code Outdoor unit amendatory capacity demand code The frequency corresponding to the total indoor units' amendatory capacity demand The frequency after the frequency limit The frequency sending to compressor control chip Indoor unit A evaporator outlet temperature Indoor unit B evaporator outlet temperature...
  • Page 40 Bit2 Bit5=1, Bit3=1, Frequency limit caused by T5. and Bit1=1. Bit1 This means Frequency limit caused by current that a Bit0 frequency limit may be caused Frequency limit caused by voltage by T4, T3, or the current. Average value of T2 (Sum T2 value of all indoor units)/(number of indoor units in good connection) Outdoor unit fan motor state...
  • Page 41 8.3.3 Outdoor unit error display New indoor Display LED STATUS Error Outdoor unit EEPROM parameter error Communication malfunction between indoor and outdoor units Communication malfunction between IPM board and outdoor main —— control board Outdoor temperature sensor (coil sensor T3,ambient sensor T4, F2/F1/F3/F6 Compressor discharge sensor T5、indoor coil outlet pipe sensor T2B) malfunction...

  • Page 42: Diagnosis And Solution

    8.4 Diagnosis and Solution 8.4.1 Indoor unit trouble shooting 8.4.1.1 Indoor unit EEPROM parameter error diagnosis and solution. Malfunction conditions Indoor or outdoor PCB main chip does not receive feedback from EEPROM chip. Potential causes Installation mistake ● Faulty PCB ●...
  • Page 43 8.4.1.2 Communication malfunction between indoor and outdoor units diagnosis and solution. Malfunction conditions If indoor unit does not receive the feedback from outdoor unit during 120 seconds. ● Wiring mistake Potential causes ● Faulty indoor or outdoor PCB Trouble shooting:...
  • Page 45 Pic 1: Use a multimeter to test the DC voltage between 2(old: L2) port and S port of outdoor unit. The red pin of multimeter connects with 2 (old: L2) port while the black pin is for S port. When AC is normal running, the voltage will move alternately between positive value and negative value.
  • Page 46 Pic 2: IPM (for 2 zone/ 3-zone) Operating Standby...
  • Page 47 Pic 2: IPM (for5 zone) Operating Standby Power PIC3: Main board LED when power on and unit standby.
  • Page 48 PIC 4: Check point button, press 1 time for check how many indoor units are connected. 8.4.1.3 Zero-crossing signal detection error diagnosis and solution. Malfunction conditions When PCB does not receive zero crossing signal feedback for 4 minutes or the zero crossing signal time interval is abnormal. ●...
  • Page 49 8.4.1.4 Indoor fan speed malfunction diagnosis and solution. When indoor fan speed is too low (300RPM) for a certain period of time, Malfunction conditions the unit ceases operation and the LED displays a failure code. Potential causes Wiring mistake ● Faulty fan assembly ●...
  • Page 50 Index 1: 1: Indoor AC fan motor Power on and set the unit running in fan mode at high fan speed. After running for 15 seconds, measure the voltage of pin1 and pin2. If the value of the voltage is less than 100V (208~240V power supply)or 50V(115V power supply), the PCB must have problems and need to be replaced.
  • Page 51 8.4.1.5 Temperature sensor malfunction diagnosis and solution. If the sampling voltage is lower than 0.06V or higher than 4.94V, Malfunction conditions the LED displays a failure. Potential causes Wiring mistake ● Faulty sensor ● Faulty PCB ● Trouble shooting: Check the connections between temperature Correct the connections.
  • Page 52 8.4.1.6 Inverter module (IPM) malfunction diagnosis and solution. Malfunction conditions When the voltage signal that IPM send to compressor drive chip is abnormal, the display LED will show “P6” and AC will turn off. ● Wiring mistake Potential causes ● IPM malfunction ●...
  • Page 53 IPM module protection Check whether the voltage range Check whether the input Regulate it to correct, then of P-N on IPM module is normal? power supply is correct? check whether the system DC277-356V for 18-27KBtu/h; 208-230V, 1N, 60Hz can work normally? DC277-410V for 36K-48KBtu/h Check whether the connecting line between main board and...
  • Page 54 8.4.1.7 Over-voltage or under-voltage protection diagnosis and solution.
  • Page 55 8.4.1.8 Compressor drive malfunction diagnosis and solution The trouble shooting is same with one of IPM module protection. Water-level alarm malfunction 8.4.1.9 diagnosis and solution Malfunction conditions If the sampling voltage is not 5V, the LED will display the failure code. Potential causes ●...
  • Page 56 8.4.1.10 Indoor units mode conflict Error Code P5(old model) or - -(new model) Malfunction conditions The indoor units cannot work cooling mode and heating at same time. Heating mode has a priority. ● Suppose Indoor unit A working in cooling mode or fan mode, and Potential causes indoor unit B is set to heating mode, then A will change to off and B will work in heating mode.
  • Page 57 8.4.2 Outdoor unit trouble shooting 8.4.2.1 E0 (Outdoor unit EEPROM parameter error) diagnosis and solution Error Code Malfunction PCB main chip does not receive feedback from EEPROM chip conditions ● Installation mistake Potential causes ● Faulty PCB Trouble shooting: Outdoor EEPROM malfunction Outdoor EEPROM malfunction Power off, then restart the Power off, then restart the...
  • Page 58 8.4.2.2 E2(Communication malfunction between indoor and outdoor units) diagnosis and solution. Error Code Malfunction Indoor unit does not receive the feedback from outdoor unit during 120 seconds or outdoor unit does not receive the conditions feedback from any one indoor unit during 180 seconds. ●...
  • Page 60 Pic 1: Use a multimeter to test the DC voltage between 2(old: L2) port and 3 port of outdoor unit. The red pin of multimeter connects with 2 (old: L2) port while the black pin is for 3 port. When AC is normal running, the voltage will move alternately between positive value and negative value.
  • Page 61 Pic 2: IPM board (for 2 zone/ 3-zone) Operating Standby...
  • Page 62 Pic 2: IPM (for5 zone) Operating Standby Power PIC3: Main board LED when power on and unit standby.
  • Page 63 PIC 4: Check point button, press 1 time for check how many indoor units are connected. 8.4.2.3 E3 (Communication malfunction between IPM board and outdoor main control board) diagnosis Error Code Malfunction PCB main chip does not receive feedback from IPM module during 60 seconds.
  • Page 65 Remark: Use a multimeter to test the DC voltage between black pin and white pin of signal wire The normal value should be around 5V. Use a multimeter to test the DC voltage between black pin and red pin of signal wire. The normal value should be around 12V.
  • Page 66 8.4.2.4 E4 (Outdoor temperature sensor (coil sensor T3,ambient sensor T4, Compressor discharge sensor T5、indoor coil outlet pipe sensor T2B) malfunction) diagnosis and solution F1/F2/F3/F4/F5 (No.A,B,C,D,E Indoor unit coil outlet temp. sensor malfunction) diagnosis and solution. Error Code E4/F1/F2/F3/F4/F5 Malfunction If the sampling voltage is lower than 0.06V or higher than 4.94V, the LED will display the failure.
  • Page 67 8.4.2.5 E5 (Over-voltage or under-voltage protection) diagnosis and solution. Error Code Malfunction conditions An abnormal voltage rise or drop is detected by checking the specified voltage detection circuit. ● Power supply problems. Potential causes ● System leakage or block ● Faulty PCB Trouble shooting: Voltage protection Check the voltage of...
  • Page 68 IPM board (for 2-zone /3-zone)
  • Page 69 Bridge rectifier (for 2-zone/3-zone) Remark: Measure the DC voltage between + and - port. The normal value should be 190V~250V. P(or E1/E2/E3)-N(GND) (for 2-zone/3-zone) Bridge rectifier (for 2-zone/3-zone) IPM Module (for 2-zone/3-zone)
  • Page 70 IPM board (for 4-zone)
  • Page 71 Bridge rectifier (for 5-zone) Remark: Measure the DC voltage between + and - port. The normal value should be 190V~250V. IPM board (for 5-zone) IPM Module (for 5-zone)
  • Page 72 8.4.2.6 E6 (PFC module protection) error diagnosis and solution. Error Code Malfunction When the voltage signal that PFC sends to main control board is abnormal, the display LED will show “E6” and AC will turn conditions off. ● Wiring mistake Potential causes ●...
  • Page 73 Inductance Two ports of the inductance...
  • Page 74 8.4.2.7 E8 (Outdoor fan speed malfunction) diagnosis and solution Error Code Malfunction conditions When outdoor fan speed keeps too low (300RPM) or too high(2400RPM) for certain time, the unit will stop and the LED will display the failure. ● Wiring mistake Potential causes ●...
  • Page 75 Index 1:  1. DC fan motor(control chip is inside fan motor) Power on and when the unit is in standby, measure the voltage of pin1-pin3, pin4-pin3 in fan motor connector. If the value of the voltage is not in the range showing in below table, the PCB must have problems and need to be replaced.
  • Page 77 8.4.2.8 P1 (High pressure protection) diagnosis and solution. Error Code Malfunction conditions If the sampling voltage is not 5V, the LED will display the failure. ● Wiring mistake Potential causes ● Faulty over load protector ● System block ● Faulty outdoor PCB Trouble shooting:...
  • Page 80 8.4.2.9 P2 (Low pressure protection) diagnosis and solution. Error Code Malfunction conditions If the sampling voltage is not 5V, the LED will display the failure. ● Wiring mistake Potential causes ● Faulty over load protector ● System block ● Faulty outdoor PCB Trouble shooting:...
  • Page 83 8.4.2.10 P3 (Current overload protection) diagnosis and solution. Error Code Malfunction conditions If the outdoor current exceeds the current limit value, the LED will display the failure. ● Wiring mistake Potential causes ● Faulty over load protector ● System block ●...
  • Page 86 8.4.2.11 P4 (Temperature protection of compressor discharge) diagnosis and solution. Error Code Malfunction conditions When the compressor discharge temperature(T5) is more than 115℃ for 10 seconds, the compressor will stop restart till T5 is less than 90℃. Potential causes ● Refrigerant leakage ●...
  • Page 88 8.4.2.12 P5 (High temperature protection of condenser) diagnosis and solution. Error Code Malfunction conditions When outdoor pipe temperature is more than 65°C, the unit will stop, and unit runs again when outdoor pipe temperature is less than 52°C Potential causes ●...
  • Page 89 8.4.2.13 P6 (Inverter module (IPM) malfunction) diagnosis and solution. Error Code Malfunction conditions When the voltage signal that IPM send to compressor drive chip is abnormal, the display LED will show “P6” and AC will turn off. Potential causes ● Wiring mistake ●...
  • Page 90 IPM module protection Check whether the voltage range Check whether the input Regulate it to correct, then of P-N on IPM module is normal? power supply is correct? check whether the system DC277-356V for 18-27KBtu/h; 208-230V, 1N, 60Hz can work normally? DC277-410V for 36KBtu/h Check whether the connecting line between main board and...

  • Page 91: Trouble Criterion Of Main Parts

    MEHSU-24CHC2 Model Indoor fan motor WZDK46-38G WZDK46-38G WZDK46-38G ZKFP-42-8-1 MEHSU-09CHN2 MEHSU-12CHN2 MEHSU-18CHF2 MEHSU-24CHF2 Model Indoor fan motor RD-280-20-8A RD-280-20-8A ZKFN-55-8-1 ZKFN-55-8-1 Outdoor unit Model MCH2U-18PHH2 MCH3U-27PHH2 MCH4U-36PHH2 MCH5U-48PHH2 Compressor ATM150D23UFZ ATF235D22UMT ATF310D43UMT ATQ360D1UMU Outdoor fan motor ZKFN-50-8-2 ZKFN-120-8-2 ZKFN-120-8-2 ZKFN-85-8-22...
  • Page 92 1.Temperature sensor checking Disconnect the temperature sensor from PCB, measure the resistance value with a tester. Temperature Sensors. Room temp.(T1) sensor, Indoor coil temp.(T2) sensor, Outdoor coil temp.(T3) sensor, Outdoor ambient temp.(T4) sensor, Compressor discharge temp.(T5) sensor. Measure the resistance value of each winding by using the multi-meter.
  • Page 93 Appendix 1 Temperature Sensor Resistance Value Table (℃--K) ℃ K Ohm ℃ K Ohm ℃ K Ohm ℃ K Ohm 115.266 12.6431 2.35774 0.62973 108.146 12.0561 2.27249 0.61148 101.517 11.5000 2.19073 0.59386 96.3423 10.9731 2.11241 0.57683 89.5865 10.4736 2.03732 0.56038 84.2190 10.000 1.96532...
  • Page 94 Appendix 2 Unit: ℃---K Discharge temp. sensor table 542.7 68.66 13.59 3.702 511.9 65.62 13.11 3.595 62.73 12.65 3.492 455.9 59.98 12.21 3.392 430.5 57.37 11.79 3.296 406.7 54.89 11.38 3.203 384.3 52.53 10.99 3.113 363.3 50.28 10.61 3.025 343.6 48.14 10.25 2.941...
  • Page 95 Appendix 3: ℃ 10 11 12 13 14 15 16 17 18 19 20 21 22 ℉ 48 50 52 54 56 58 60 62 64 66 68 70 72 ℃ 23 24 25 26 27 28 29 30 31 32 33 34 35 ℉...
  • Page 96 3. IPM continuity check Turn off the power, let the large capacity electrolytic capacitors discharge completely, and dismount the IPM. Use a digital tester to measure the resistance between P and UVWN; UVW and N. Normal Normal resistance Digital tester Digital tester resistance value...
  • Page 97 Position Resistance Value YDK70- YDK53- YDK180-8GB YSK27-4G YSK68-4B YDK45-6B YSK25-6L 6FB(B) 56Ω±8% 24.5Ω±8% 317Ω±8% 145Ω±8% 345Ω±8% 627Ω±8% 88.5Ω±8% Black - (20℃) (20℃) (20℃) (20℃) (20℃) (20℃) (20℃) 76Ω±8% 19Ω±8% 252Ω±8% 88Ω±8% 150Ω±8% 374.3Ω±8% 138Ω±8% Red - Yellow (20℃) (20℃) (20℃) (20℃) (20℃) (20℃)
  • Page 98 6.EXV check Disconnect the connectors.
  • Page 99 Resistance to EXV coil Color of lead wire Normal Value Red- Blue Red - Yellow About 50Ω Brown-Orange Brown-White...
  • Page 100 Red- Blue Red - Yellow...
  • Page 101 Brown-Orange...
  • Page 102 Brown-White...

  • Page 103: Disassembly Instructions

    9. Disassembly Instructions Note: This part is for reference, the photos may have slight difference with your machine.  MCH2U-18PHH2 (WCA30 metal plate) Part name Procedures Remarks How to remove the fan assembly assembly. 1) Turn off the air conditioner ②...
  • Page 104 cover. (3 screws) 6) Remove the cover of electrical control box. ⑦ 7) Disconnect the fan motor connector CN14(3p,white) from the IPM board. ⑧ 8) Remove the fan motor after unfastening four fixing screws. Panel plate How to remove the panel plate.
  • Page 105 Screws of front panel 2) Remove the screws of big handle, and remove the big handle.(4 screws) 3) Remove two screws of terminal board and seven Screws of big handle screws of right-rear panel, and remove the right-rear panel. Screws of terminal board Screws of right- rear panel...
  • Page 106 Screws of right- rear panel Electrical How to remove the electrical parts parts. 1) Perform work of item 1,2. 2) Remove the four screws fixing the IPM board. PCB board IPM board Unfasten the connector ④ of the reactor. Unfasten the connector of the compressor.
  • Page 107 Remove the IPM board. Disconnect the connectors and wires connected from PCB and other parts. Connectors: CN17:T3/T4 temperature sensor CN15 CN17 CN18/CN19 CN25/CN23 (2p/2p,white) CN7: Discharge temperature sensor (2p,white) CN15:T2B-A,B temperature sensor (2p/2p,white) CN18/CN19: Electronic expansive valve A,B (6p/6p,red/red) CN25/CN23: S-A,S-B (3p/3p,white/white) Wires: CN1/CN2: 4-way valve (blue-blue)
  • Page 108 Compressor How to remove the compressor. 1) Perform work of item 1,2. 2) Remove the cover of electrical control box. 3) Extract refrigerant gas. 4) Remove the sound insulation material and crankcase heating cable. 5) Remove terminal cover of compressor, and disconnect wires of ⑥...
  • Page 109 ⑦ Reactor How to remove the reactor 1) Perform work of item 2 2) Unfasten the connector between IPM and reactor. ② 3) Remove three screws of reactor, and remove the reactor. Screws of cover of inductance...

  • Page 110: Mch3U-27Phh2 (Wd30 Metal Plate)

    The 4-way How to remove the 4-way valve valve 1) Perform work of item 2. 2) Extract refrigerant gas. Coil 3) Remove the electrical parts Welded parts from item 3. 4) Remove fixing screw of the coil, and remove the coil. 5) Detach the welded parts of 4-way valve and pipe.
  • Page 111 2) Remove the screws of big handle, and remove the big handle.(4 screws) 3) Remove the screws of top cover, and remove the top cover. (4 screws) 4) Remove the screws of right front side panel, and Screws of top cover remove the right front side panel (1 screws) 5) Remove the screws of front...
  • Page 112 Screws of front panel Screws of front panel Screws of right-rear panel...
  • Page 113 Screws of terminal board How to remove the fan assembly. assembly 1) Remove the top cover, right front side panel and ② front panel from item 1.step 2) Remove the hex nut fixing the fan. ④ 3) Remove the fan. 4) Remove the cover of electrical control box cover.
  • Page 114 connector CN14(5p,white) from the IPM board. ⑤ Remove the fan motor after unfastening four fixing screws. How to remove the electrical ③ parts. Electrical parts 1) Perform work of item 1,2. 2) Remove the four screws fixing the IPM board. Unfasten the connector of the reactor.
  • Page 115 CN1(5p,white) CN14(3p,white) CN3(red or brown) CN5(blue) ⑥ Remove the IPM board. Disconnect the CN15 CN7 CN17 connectors and wires CN18/CN19/CN22 connected from PCB and other parts. Connectors: CN17:T3/T4 temperature sensor (2p/2p,white) CN20 CN7: Discharge temperature sensor CN23 (2p,white) CN25 CN12:Ttop temperature sensor(2p,white) CN15:T2B-A,B,C temperature sensor (2p/2p/2p,white)
  • Page 116 Wires: CN1/CN2: 4-way valve (blue-blue) CN5/CN6: Crankcase heating cable (red-red) CN3:L1-IN (red) CN4:L2-IN (black) Disconnect the ⑧ grounding wire (yellow-green) after removing the big handle and the right-rear panel. 9) Remove the PCB board. How to remove the compressor. Compressor 1) Perform work of item 1,2,3.
  • Page 117 7) Remove the hex nuts and washers fixing the ⑦ compressor to bottom plate. 8) Lift the compressor. Reactor How to remove the reactor 1) Perform work of item 1,2 2) Unfasten the connector between IPM and reactor. 3) Remove two screws of cover of inductance, and remove the cover of Screws of...
  • Page 118 The 4-way How to remove the 4-way valve valve Coil 1) Perform work of item 1,2. 2) Extract refrigerant gas. Welded parts 3) Remove the electrical parts from item 3. 4) Remove fixing screw of the coil, and remove the coil. 5) Detach the welded parts of 4-way valve and pipe.
  • Page 119 Turn off the power breaker. Screws of top cover 2) Remove the screws of big handle, and remove the big handle.(4 screws) 3) Remove the screws of top cover, and remove the top cover. (4 screws) Screws of top cover 4) Remove the screws of right front side panel, and remove the right front side...
  • Page 120 Screws of front panel Screws of front panel Screws of right-rear panel...
  • Page 121 Screws of terminal board How to remove the fan assembly. assembly 1) Remove the top cover, ② right front side panel and front panel from item 1.step 2) Remove the hex nut fixing the fan. 3) Remove the fan. 4) Unfix the hooks and ④...
  • Page 122 Remove the fan motor after unfastening four fixing screws. ⑥ How to remove the electrical parts. Electrical parts 1) Perform work of item 1,2. Unfasten the connector of the reactor. Unfasten the connector PCB board Driver board of the compressor. ③...
  • Page 123 connected from PCB and other CN55 parts. CN18/CN17/CN21/CN20 Connectors: CN8:T3/T4 temperature sensor (2p/2p,white) CN30/ CN33: Discharge temperature sensor (2p,white) CN29/ CN13:T2B-A,B,C,D temperature sensor (2p/2p/2p/2p,white) CN18/CN17/CN21/CN20: Electronic expansive valve A,B,C,D (6p/6p/6p,red/red/red) CN30/CN29/CN28/CN27: S-A,S-B,S- C,S-D (3p/3p/3p/3p,white) CN9: High and low pressure switch (2p/2p, white) CN8 CN9 Wires:...
  • Page 124 How to remove the compressor. Compressor 1) Perform work of item 1,2,3. 2) Remove the electrical control box and partition plate. 3) Extract refrigerant gas. 4) Remove the sound insulation material and crankcase heating cable. 5) Remove terminal cover of compressor, and disconnect wires of compressor thermo and...
  • Page 125 The 4-way How to remove the 4-way valve valve 1) Perform work of item 1,2. 2) Extract refrigerant gas. 3) Remove the electrical parts from item 3. 4) Remove fixing screw of the coil, and remove the coil. 5) Detach the welded parts of 4-way valve and pipe.
  • Page 126 breaker. 2) Remove the screws of air outlet grille(8 screws) 3) Remove the hex nut fixing the fan. 4) Remove the fan. 5) Remove the screws of top cover, and remove the top cover. (4 screws) 6) Remove the screws of front side panel, and remove the front side panel (1 screw)
  • Page 127 7) Disconnect the fan motor connectors FAN1(3p,white) and FAN2(3p,white) from DC motor driver board. 8) Remove the fan motor after unfastening fixing screws. Panel plate How to remove the panel plate. 4) Remove big handle.(2 screws) and water collector(2 screws) 5) Remove 2 screws of terminal board and 15 screws of right-rear panel,...
  • Page 128 2) Disconnect the fan motor Connector(5p,white) from the IPM board. Disconnect following 8 pieces of connection wires and connectors between IPM and other parts. CN2(yellow) CN1(red) CN6(black) CN3(yellow) U、V、W(black) CN9(10p,white) 4) Remove the fixing screws then remove the IPM board. Disconnect the connectors and wires connected from PCB and other...
  • Page 129 CN8: Discharge temperature sensor (2p,white) CN12：Heatsink temperature sensor(2p,red) CN9:T3/T4 temperature sensor (2p/2p,white) CN11:T2B-A,B,C,D,E temperature sensor (2p/2p/2p/2p/2p,white) CN15/CN23/CN26/CN30/CN33: Electronic expansive valve (6p/6p/6p/6p/6p,red) CN37/CN29/CN21/CN16/CN13: S- A,S-B,S-C,S-D,S-E (3p/3p/3p/3p/3p,white) CN10: High and low pressure switch (2p/2p, white) Wires: CN17/CN18: 4-way valve (blue-blue) CN19/CN20: connected to crankcase heating cable.
  • Page 130 Compressor How to remove the compressor. 1) Perform work of item 1 step 5~6 and item 2.. 2) Extract refrigerant gas. 3) Remove the sound insulation material and crankcase heating cable. 4) Remove terminal cover of compressor, and disconnect wires of crankcase electric heater and compressor from the terminal.
  • Page 131 The 4-way How to remove the 4-way valve valve 6) Perform work of item 1 step 5~6 and item 2.. 7) Extract refrigerant gas. 8) Remove the electrical parts from item 3. 9) Remove fixing screw of the coil, and remove the coil. 10) Detach the welded parts of 4-way valve and pipe.

This manual is also suitable for:

Mch3u-27phh2Mch5u-48phh2Mch4u-36phh2

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