Midea MEHS-09NIH2 Service Manual
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Midea MEHS-09NIH2 Service Manual

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Revision A: 1403100001, Content updated.
Model Numbers:
MEHS-09NiH2/MCHS-09NiH2 MEHS-09NIH1/ MCHS-09NiH1
MEHS-12NIH1/MCHS-12NiH1 MEHS-18NIH2/ MCHS-18NiH2

Table of Contents

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2.
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4.
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7.
8.
9.
Disassembly Instructions
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.
This service is only for service engineer to use.
nEOLA MOnO SpLIt dC InVERtER
AIR COndItIOnER
SERVICE MAnUAL
MEHS-12NIH2/ MCHS-12NiH2
MEHS-22NIH2/ MCHS-22NiH2
Mono DC

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Summary of Contents for Midea MEHS-09NIH2

  • Page 1: Table Of Contents

    MOnO SpLIt dC InVERtER AIR COndItIOnER Mono DC SERVICE MAnUAL Revision A: 1403100001, Content updated. Model Numbers: MEHS-09NiH2/MCHS-09NiH2 MEHS-09NIH1/ MCHS-09NiH1 MEHS-12NIH2/ MCHS-12NiH2 MEHS-12NIH1/MCHS-12NiH1 MEHS-18NIH2/ MCHS-18NiH2 MEHS-22NIH2/ MCHS-22NiH2 Table of Contents Precaution Dimension Refrigerant Cycle Diagram Wiring Diagram Installation Details...
  • Page 2 CONTENTS 1. Precaution ..............................1 1.1 Safety Precaution .......................... 1 1.2 Warning ............................1 2. Part Names And Functions ......................... 4 2.1 Model Names of Indoor/Outdoor units ..................4 3. Dimension ..............................5 3.1 Indoor Unit ............................. 5 3.2 Outdoor Unit ..........................6 5.

  • Page 3: Precaution

    Sharp edges could cause injury, be especially careful of the case edges and the fins on the 1. Precaution condenser and evaporator.  For installation, always contact the 1.1 Safety Precaution dealer or an authorized service center.  To prevent injury to the user or other ...
  • Page 4 There is risk of electric shock or fire. product.  Stop operation and close the window It can avoid vibration of water leakage.  in storm or hurricane. If possible, remove Do not install the product where the the product from the window before the noise or hot air from the outdoor unit could hurricane arrives.
  • Page 5  Use a firm stool or ladder when cleaning or maintaining the product. Be careful and avoid personal injury.  Replace the all batteries in the remote control with new ones of the same type. Do not mix old and new batteries or different types of batteries.

  • Page 6: Part Names And Functions

    2. Part Names And Functions 2.1 Model Names of Indoor/Outdoor units Series Capacity Indoor units Outdoor units MEHS-09NiH2 MCHS-09NiH2 MEHS-09NIH1 MCHS-09NIH1 MEHS-12NIH2 MCHS-12NiH2 Inverter MEHS-12NIH1 MCHS-12NIH1 MEHS-18NIH2 MCHS-18NiH2 MEHS-22NIH2 MCHS-22NiH2...

  • Page 7: Dimension

    3. Dimension 3.1 Indoor Unit Model MEHS-09NiH2 (26.8in) (7.0in) (10.0in) MEHS-09NIH1 MEHS-12NiH2 770mm 188mm 255mm (30.3in) (7.4in) (10.0in) MEHS-12NIH1 905mm 198mm 275mm MEHS-18NIH2 (35.6in) (7.8in) (10.8in) 1030mm 218mm 315mm MEHS-22NIH2 (40.6in) (8.6in) (12.4in)

  • Page 8: Outdoor Unit

    Model R(mm) L(mm) H(mm) Dimension of installation hole(mm) MEHS-09NiH2 92mm MEHS-09NIH1 (3.6in) (6.7in) (1.8in) MEHS-12NIH2 95mm 170mm 45mm Φ65mm(2.56in) MEHS-12NIH1 (3.7in) (6.7in) (1.8in) 80mm 100mm 45mm MEHS-18NIH2 (3.1in) (3.9in) (1.8in) Model R(mm) L(mm) H(mm) Dimension of installation hole(mm) 163mm 293mm...
  • Page 9 More than 30cm(11.8in) More than 60cm(23.6in) (Service space) More than 30cm(11.8in) More than 60cm(23.6in) More than 70cm(27.6in) Note: The above drawing is only for reference. The appearance of your units may be different. Model MCHS-09NiH2 (27.6in) (9.4in) (21.3in) (29.8in) (18.0in) (9.8in) 660mm 265mm...

  • Page 10: Refrigerant Cycle Diagram

    5. Refrigerant Cycle Diagram INDOOR OUTDOOR CHECK VALVE LIQUID SIDE (Heating Model only) 2-WAY VALVE CAPILIARY TUBE HEAT HEAT EXCHANGE EXCHANGE (EVAPORATOR) (CONDENSER) GAS SIDE REVERSING VALVE 3-WAY VALVE (Heating Model only) ACCUMULATOR COOLING COMPRESSOR HEATING...

  • Page 11: Wiring Diagram

    6. Wiring Diagram 6.1 Indoor Unit MEHS-09NiH1, MEHS-12NiH1 MEHS-09NiH2, MEHS-12NiH2, MEHS-18NiH2...
  • Page 12 MEHS-22NiH2...

  • Page 13: Outdoor Unit

    6.2 Outdoor Unit MCHS-09NiH1, MCHS-12NiH1...
  • Page 14 MCHS-09NiH2, MCHS-12NiH2...
  • Page 15 MCHS-18NiH2 MCHS-22NiH2...
  • Page 16 For MCHS-12NiH2, For MCHS-09NiH1 , MCHS-12NiH1,...
  • Page 17 MCHS-09NiH2 MCHS-18NiH2,...
  • Page 18 MCHS-22NiH2,...

  • Page 19: Installation Details

    7.3 Pipe length and the elevation 7 Installation Details Pipe size 7.1 Wrench torque sheet for Models installation Liquid Additional tightening Outside diameter Torque 3/8in 1/4in torque MEHS-09NiH2+ MCHS-09NiH2 (Ф9.52mm) (Ф6.35mm) Ф6.35mm 1/4in 1500N.cm(153kgf.cm) 1600N.cm(163kgf.cm) 3/8in 1/4in MEHS-09NIH1+MCHS-09NIH1 Ф9.52mm 3/8in 2500N.cm(255kgf.cm) 2600N.cm(265kgf.cm)

  • Page 20: Installation For The First Time

    4) Fully open the handle Lo of the manifold valve. 7.4 Installation for the first time 5) Operate the vacuum pump to evacuate. Air and moisture in the refrigerant system have 6) Make evacuation for 30 minutes and check whether the compound meter indicates undesirable effects as below: -0.1Mpa(14.5Psi).

  • Page 21: Adding The Refrigerant After Running The System For Many Years

    for 3 seconds then closing it for 1 minute; repeat purge the air (be careful of the liquid 3 times. refrigerant). After purging the air, use a torque wrench to 3) Put the charging cylinder onto the electronic tighten the flare nut on the 2-way valve. scale and record the weight.

  • Page 22: Re-Installation While The Outdoor Unit Need To Be Repaired

    slightly to purge air from the charge hose for 5 the gauge indicates 0.3Mpa(43.5Psi) to 0.5 seconds and then close it quickly. Mpa(72.5Psi). 4). Set the 2-way valve to the close position. 6). Disconnect the charge set and the charging 5).
  • Page 23 to check for gas leakage. 2. Refrigerant charging Procedure: 1). Connect the charge hose to the charging cylinder, open the 2-way valve and the 3-way valve Connect the charge hose which you disconnected from the vacuum pump to the valve at the bottom of the cylinder. If the refrigerant is R410A, make the cylinder bottom up to ensure liquid charge.

  • Page 24: Operation Characteristics

    8. Operation Characteristics Temperature Cooling operation Heating operation Drying operation Mode ＞10℃ ≥17℃ ≤30℃ Room temperature (62℉) (86℉) (50℉) 0℃～50℃ (32℉～122℉) -15℃～30℃ 0℃～50℃ -15℃～50℃ Outdoor temperature (5℉～122℉) (5℉～86℉) (32℉～122℉) (For the models with low temperature cooling system) CAUTION: 1. If the air conditioner is used beyond the above conditions, certain safety protection features may come into operation and cause the unit to operate abnormally.

  • Page 25: Electronic Function

    9. Electronic Function 9.1 Abbreviation T1: Indoor room temperature T2: Coil temperature of evaporator T3: Coil temperature of condenser T4: Outdoor ambient temperature T5: Compressor discharge temperature 9.2 Display function 9.2.1 Icon explanation on indoor display board. This indicator illuminates when the Defrost air conditioner starts defrosting Indicator...

  • Page 26: Main Protection

    9.3 Main Protection Preheating mode: A weak current flow through the coil of 9.3.1 Three minutes delay at restart for compressor from the wiring terminal of the compressor compressor, then the compressor is heated 1 minute delay for the 1 time stand-up and 3 without operation.

  • Page 27: Operation Modes And Functions

    9.4 Operation Modes and Functions If users switch on AC by remote controller, the compressor will run at the Fmax frequency for 7 9.4.1 Fan mode minutes according to the outdoor ambient temp. (1) Outdoor fan and compressor stop. During the 7 minutes, the frequency limitation is (2) Temperature setting function is disabled, active.
  • Page 28 I3COOL Decrease High I2COOL Medium Hold I1COOL Resume 9.4.3 Heating Mode I3COOL, I2COOL,I1COOL mean different 9.4.3.1 Compressor running rules running current value. The maximum operation frequency of the Off: Compressor stops. compressor after starting submits to the Decrease: Decrease the running frequency to following rule.
  • Page 29 During the 7 minutes, the frequency limitation is active. 7 minutes later, the compressor running I3HEAT frequency will be controlled as below: Decrease I2HEAT +5.0 Hold I1HEAT +4.5 Resume +3.5 +3.0 I3HEAT, I2HEAT,I1HEAT mean different +2.5 running current value. Off: Compressor stops. +2.0 Decrease: Decrease the running frequency to +1.5...
  • Page 30 Frequency F2 FrequencyF8 Compressor 4-way valve Medium Outdoor fan High Indoor fan 9.4.3.4 Defrosting mode Indoor fan breeze(10s) Condition of defrosting: ----T4＞0℃, When the units are running, if the following two no longer than 10m items are satisfied, the units start defrosting: The units run with T3＜3℃...
  • Page 31 compressor will stop. than 10℃, the compressor will stop and not ----T2<48℃ or T2 stays in 48℃~ TEH2℃ for 6 resume until room temperature exceeds 12℃. minutes, the frequency will not be limited by T2. 9.4.5.4 Evaporator anti-freezing protection, condenser high temperature protection and ----T2>60℃, the compressor will stop and restart when T2<48℃.
  • Page 32 now, it will not start up firstly after setting the sleep mode. “timer off” function. And when reaching the 9.4.9 Auto-Restart function setting time, the timer LED will be off and the The indoor unit is equipped with auto-restart AC running mode has not been changed. function, which is carried out through an 9.4.7.7 The setting time is relative time.

  • Page 33: Troubleshooting

    10. Troubleshooting Safety Electricity power is still kept in capacitors even the power supply is shut off. Do not forget to discharge the electricity power in capacitor. Electrolytic Capacitors (HIGH VOLTAGE! CAUTION!) For other models, please connect discharge resistance (approx.100Ω 40W) or soldering iron (plug) between +, - terminals of the electrolytic capacitor on the contrary side of the outdoor PCB.

  • Page 34: Indoor Unit Error Display

    10.1 Indoor Unit Error Display Operation lamp Timer lamp Display LED STATUS ☆ 1 time Indoor unit EEPROM parameter error ☆ 2 times Indoor / outdoor units communication error ☆ 3 times Zero-crossing signal detection error ☆ 4 times Indoor fan speed has been out of control Indoor room temperature sensor T1 open circuit or short ☆...

  • Page 35: Outdoor Unit Error Display

    10.2 Outdoor unit error display For MCHS-12NiH2, There’s a LED light on the outdoor PCB which is blue color. After power on, it will be slow flash(0.2Hz) when the unit is in standby and quick flash (2.5Hz) if the unit has some problems, it will be solid light when the unit is running.
  • Page 36 For MCHS-09NiH1 , MCHS-12NiH1, There’s a LED light on the outdoor PCB which is blue color. After power on, it will be slow flash(0.2Hz) when the unit is in standby and quick flash (2.5Hz) if the unit has some problems.
  • Page 37 MCHS-09NiH2, The picture of PCB above is only for reference. LED 3 is a red light and for the PCB POWER display. LED 4 is a yellow light. After power on, it will be slow flash(0.2Hz) when the unit is in standby and quick flash (2.5Hz) if the unit has some problems.
  • Page 38 MCHS-18NiH2, LED3 & LED4 LED2 LED1 (red) (green) (yellow) (red) standby operating LED2 slow flashing(0.2Hz) LED1 The picture of PCB above is only for reference. LED 1 is a red light and for the PCB POWER display. LED 2 is a yellow light. After power on, it will be slow flash(0.2Hz) when the unit is in standby and quick flash (2.5Hz) if the unit has some problems.
  • Page 39 LED4 LED3 Problems IU display (Green) (Red) standby for normal Operation normally ☆ IPM malfunction or IGBT over-strong current protection Over voltage or too low voltage protection ☆ Over voltage or too low voltage protection ☆ Inverter compressor drive error ☆...

  • Page 40: Diagnosis And Solution

    10.3 Diagnosis and Solution 10.3.1 EEPROM parameter error diagnosis and solution(E0/F4) E0/F4 Error Code Malfunction decision Indoor or outdoor PCB main chip does not receive feedback conditions from EEPROM chip. Supposed causes Installation mistake ● PCB faulty ● Trouble shooting: EEPROM: a read-only memory whose contents can be erased and reprogrammed using a pulsed voltage.
  • Page 41 10.3.2 Indoor / outdoor unit’s communication diagnosis and solution(E1) Error Code Malfunction decision Indoor unit does not receive the feedback from outdoor unit during conditions seconds and this condition happens four times continuously. Supposed causes Wiring mistake ● Indoor or outdoor PCB faulty ●...
  • Page 42 Remark: Use a multimeter to test the DC voltage between L2 port and S port of outdoor unit. The red pin of multimeter connects with L2 port while the black pin is for S port. When AC is normal running, the voltage will move alternately between -50V to 50V.
  • Page 43 10.4.3 Zero crossing detection error diagnosis and solution(E2) Error Code Malfunction decision When PCB does not receive zero crossing signal feedback for 4 conditions minutes or the zero crossing signal time interval is abnormal. Supposed causes Connection mistake ● PCB faulty ●...
  • Page 44 10.4.4 Fan speed has been out of control diagnosis and solution(E3) Error Code Malfunction decision When indoor fan speed keeps too low (300RPM) for certain time, conditions the unit will stop and the LED will display the failure. Supposed causes Wiring mistake ●...
  • Page 45 Index 1: 1:Indoor or Outdoor DC Fan Motor(control chip is in 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 has problems and need to be replaced.
  • Page 46 10.4.5 Open circuit or short circuit of temperature sensor diagnosis and solution(E5) Error Code Malfunction decision If the sampling voltage is lower than 0.06V or higher than 4.94V, conditions the LED will display the failure. Supposed causes Wiring mistake ● Sensor faulty ●...
  • Page 47 10.4.6 Refrigerant Leakage Detection diagnosis and solution(EC) Error Code Malfunction decision Define the evaporator coil temp.T2 of the compressor just starts conditions running as Tcool. In the beginning 5 minutes after the compressor starts up, if T2 ＜Tcool－2℃ does not keep continuous 4 seconds and this situation happens 3 times, the display area will show “EC”...
  • Page 48 10.4.7 IPM malfunction or IGBT over-strong current protection diagnosis and solution(P0) Error Code Malfunction decision When the voltage signal that IPM send to compressor drive chip conditions is abnormal, the display LED will show “P0” and AC will turn off. Supposed causes Wiring mistake ●...
  • Page 49 For example: Note: The photos below are only for reference, it’s may be not same totally with the ones on your side.
  • Page 51 10.4.8 Over voltage or too low voltage protection diagnosis and solution(P1) Error Code Malfunction decision An abnormal voltage rise or drop is detected by checking the conditions specified voltage detection circuit. Supposed causes Power supply problems. ● System leakage or block ●...
  • Page 52 10.4.9 High temperature protection of compressor top diagnosis and solution(P2) Error Code Malfunction decision If the sampling voltage is not 5V, the LED will display the failure. conditions Supposed causes Power supply problems. ● System leakage or block ● PCB faulty ●...
  • Page 53 10.4.10 Inverter compressor drive error diagnosis and solution(P4) Error Code Malfunction decision An abnormal inverter compressor drive is detected by a special conditions detection circuit, including communication signal detection, voltage detection, compressor rotation speed signal detection and so on. Supposed causes Wiring mistake;...
  • Page 54 Main parts check 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 55 Appendix 1 Temperature Sensor Resistance Value Table for T1,T2,T3,T4 (℃--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 11.5 2.19073 0.59386 96.3423 10.9731 2.11241 0.57683 89.5865...
  • Page 56 Appendix 2 Temperature Sensor Resistance Value Table for T5 (℃--K) ℃ ℉ ℃ ℉ ℃ ℉ ℃ ℉ K Ohm K Ohm K Ohm K Ohm 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...
  • Page 57 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 58 2.Compressor checking Measure the resistance value of each winding by using the tester. Position Resistance Value DA108X1C-23EZ DA108X1C-20FZ3 DA130M1C-31FZ DA150S1C-20FZ Blue - Red 0.71Ω 1.77Ω 0.95Ω 1.1Ω (20℃/68℉) (20℃/68℉) (20℃/68℉) Blue - Black (20℃/68℉) Red - Blue...
  • Page 59 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. Digital tester Normal resistance value Digital tester Normal resistance value (+)Red...
  • Page 60 5: Pressure On Service Port Cooling chart: ℉(℃) （23.89） （29.44） （35） （40.56） （46.11） 70/59 10.1 75/63 10.7 80/67 11.2 ℉(℃) 75 （23.89） 85 （29.44） 105 （40.56） 115 （46.11） （35） 70/59 75/63 80/67 ℉(℃) 75 （23.89） 85 （29.44） 105 （40.56） 115 （46.11） （35）...
  • Page 61 Heating Chart: ℉ 57/53 47/43 37/33 27/23 17/13 (℃) (13.89/11.67) (8.33/6.11) (2.78/0.56) (-2.78/-5) (-8.33/-10.56) 30.3 28.5 25.3 22.8 20.8 32.5 30.0 26.6 25.4 23.3 33.8 31.5 27.8 26.3 24.9 ℉ 57/53 47/43 37/33 27/23 17/13 (℃) (13.89/11.67) (8.33/6.11) (2.78/0.56) (-2.78/-5) (-8.33/-10.56) ℉...

This manual is also suitable for:

Mehs-12nih1Mehs-09nih1Mehs-18nih2Mehs-12nih2Mehs-22nih2Mchs-09nih2 ... Show all

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