Midea Mini C Series Service Manual

Commercial air conditioners

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Service

Manual

8KW

Model:

Mini C

10-12KW

1 phase, 220-240V, 50/60Hz

MDV-V80W/DHN1(C)

MDV-V100W/DHN1(C)

MDV-V120W/DHN1(C)

MDV-V140W/DHN1(C)

MDV-V160W/DHN1(C)

Commercial Air Conditioners

14-16KW

R410A

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Summary of Contents for Midea Mini C Series

Page 1 R410A Commercial Air Conditioners Service Manual Mini C 10-12KW 14-16KW Model: 1 phase, 220-240V, 50/60Hz MDV-V80W/DHN1(C) MDV-V100W/DHN1(C) MDV-V120W/DHN1(C) MDV-V140W/DHN1(C) MDV-V160W/DHN1(C)
Page 2 Mini C Series VRF 50/60Hz CONTENTS Part 1 General Information ................3 Part 2 Component Layout and Refrigerant Circuits ........7 Part 3 Control ....................18 Part 4 Field Settings ..................28 Part 5 Electrical Components and Wiring Diagrams ........33...
Page 3 Mini C Series VRF 50/60Hz...
Page 4 Mini C Series VRF 50/60Hz Part 1 General Information 1 Indoor and Outdoor Unit Capacities ............4 2 External Appearance ................5 3 Combination Ratio .................. 6...
Page 5 Mini C Series VRF 50/60Hz 1 Indoor and Outdoor Unit Capacities 1.1 Indoor Units Table 1-1.1: Indoor unit abbreviation codes Abbreviation Abbreviation Type Type code code One-way Cassette High Static Pressure Duct Two-way Cassette Wall-mounted Compact Four-way Cassette Ceiling & Floor...
Page 6 Mini C Series VRF 50/60Hz 2 External Appearance 2.1 Indoor Units Table 1-2.1: Indoor unit appearance One-way Cassette Two-way Cassette Compact Four-way Cassette Four-way Cassette Medium Static Pressure Duct High Static Pressure Duct Wall-mounted Ceiling & Floor Floor Standing 2.2 Outdoor Units Table 1-2.4: Outdoor unit appearance...
Page 7 Mini C Series VRF 50/60Hz 3 Combination Ratio Sum of capacity indexes of the indoor units Combination ratio = Capacity index of the outdoor unit Table 1-4.1: Indoor and outdoor unit combination ratio limitations Type Minimum combination ratio Maximum combination ratio...
Page 8 Mini C Series VRF 50/60Hz Part 2 Component Layout and Refrigerant Circuits 1 Piping Diagrams ..................8 2 Refrigerant Flow Diagrams ..............10...
Page 9 Mini C Series VRF 50/60Hz 1 Piping Diagrams Figure 2-1.1: 80 model Piping diagram Figure 2-1.2: 100/120 model Piping diagram...
Page 10 Mini C Series VRF 50/60Hz Figure 2-1.3: 140/160 model Piping diagram Key components: 1. Oil separator: Separates oil from gas refrigerant pumped out of the compressor and quickly returns it to the compressor. Separation efficiency is up to 99%. 2. Gas-liquid separator: Stores liquid refrigerant and oil to protect compressor from liquid hammering.
Page 11 Mini C Series VRF 50/60Hz 2 Refrigerant Flow Diagrams Cooling operation Figure 2-3.1: 80 model refrigerant flow during cooling operation Figure 2-3.2: 100/120 model refrigerant flow during cooling operation...
Page 12 Mini C Series VRF 50/60Hz Figure 2-3.3: 140/160 model refrigerant flow during cooling operation Oil return operation in cooling mode Figure 2-3.4: 80 model refrigerant flow during oil return operation in cooling mode...
Page 13 Mini C Series VRF 50/60Hz Figure 2-3.5: 100/120 model refrigerant flow during oil return operation in cooling mode Figure 2-3.6: 140/160 model refrigerant flow during oil return operation in cooling mode...
Page 14 Mini C Series VRF 50/60Hz Heating operation Figure 2-3.7: 80 model refrigerant flow during heating operation Figure 2-3.8: 100/120 model refrigerant flow during heating operation...
Page 15 Mini C Series VRF 50/60Hz Figure 2-3.9: 140/160 model refrigerant flow during heating operation Oil return operation in heating mode Figure 2-3.10: 80 model refrigerant flow during oil return operation in heating mode...
Page 16 Mini C Series VRF 50/60Hz Figure 2-3.11: 100/120 model refrigerant flow during oil return operation in heating mode Figure 2-3.12: 140/160 model refrigerant flow during oil return operation in heating mode...
Page 17 Mini C Series VRF 50/60Hz Defrosting operation Figure 2-3.13: 80 model refrigerant flow during defrosting operation Figure 2-3.14: 100/120 model refrigerant flow during defrosting operation...
Page 18 Mini C Series VRF 50/60Hz Figure 2-3.15: 140/160 model refrigerant flow during defrosting operation...
Page 19 Mini C Series VRF 50/60Hz Part 3 Control 1 General Control Scheme Flowchart ............19 2 Stop Operation ..................20 3 Standby Control ..................21 4 Startup Control ..................22 5 Normal Operation Control ..............23 6 Protection Control................. 24...
Page 20 Mini C Series VRF 50/60Hz 1 General Control Scheme Flowchart Sections 3-2 to 3-7 on the following pages detail when each of the controls in the flowchart below is activate*d. Stop operation  Abnormal shutdown  System stop Standby control ...
Page 21 Mini C Series VRF 50/60Hz 2 Stop Operation The stop operation occurs for one of the two following reasons: 1. Abnormal shutdown: in order to protect the compressors, if an abnormal state occurs the system makes a 'stop with thermo off' operation and an error code is displayed on the outdoor unit digital displays.
Page 22 Mini C Series VRF 50/60Hz 3 Standby Control 3.1 Crankcase Heater Control The crankcase heater is used to prevent refrigerant from mixing with compressor oil when the compressor is stopped. The crankcase heater is controlled according to outdoor ambient temperature and the compressor on/off state. When the outdoor ambient temperature is above 3°C or the compressor is running, the crankcase heater is off;...
Page 23 Mini C Series VRF 50/60Hz 4 Startup Control 4.1 Compressor Startup Delay Control When the ODU is powered on again and the compressor delays about 7 minutes to start. After the compressor stops running, it takes about 4 minutes to restart, in order to prevent frequent compressor on/off and to equalize the pressure within the refrigerant system.
Page 24 Mini C Series VRF 50/60Hz 5 Normal Operation Control 5.1 Component Control during Normal Operation Table 3-5.1: Component control during normal cooling operation Wiring diagram Component 8~16kW Control functions and states label Inverter compressor COMP Controlled according to load requirement ●...
Page 25 Mini C Series VRF 50/60Hz 6 Protection Control 6.1 High Pressure Protection Control This control protects the system from abnormally high pressure and protects the compressors from transient spikes in pressure. Figure 3-6.1: High pressure protection control Normal operation > 4.4MPa <...
Page 26 Mini C Series VRF 50/60Hz 6.4 Compressor and Inverter Module Protection Control This control protects the compressors from abnormally high currents and protects the inverter modules from abnormally high temperatures. Figure 3-6.4: Compressor current protection control Normal operation Current ≥ Current Current <...
Page 27 Mini C Series VRF 50/60Hz 7 Special Control 7.1 Oil Return Operation In order to prevent compressors from running out of oil, the oil return operation is conducted to recover oil that has flowed out of the compressor(s) and into the piping system. This operation is performed for all units including units that are in standby.
Page 28 Mini C Series VRF 50/60Hz 7.2 Defrosting Operation In order to recover heating capacity, the defrosting operation is conducted when the outdoor unit heat exchanger is performing as an evaporator. The defrosting operation is controlled according to outdoor ambient temperature, outdoor heat exchanger temperature, indoor heat exchanger temperature and outdoor unit running time.
Page 29 Mini C Series VRF 50/60Hz Part 4 Field Settings 1 Outdoor Unit Field Settings ..............29...
Page 30 Mini C Series VRF 50/60Hz 1 Outdoor Unit Field Settings Figure 4-1.1: 80 model outdoor unit main PCB switches Dial switches Check button Digital display Table 4-1.1: 80 model outdoor unit main PCB switch settings Switch Switch Setting Description positions Spot check button and force cooling button(long pressed over 5 seconds 1.Spot check...
Page 31 Mini C Series VRF 50/60Hz Figure 4-1.2: 100/120 model outdoor unit main PCB switches and communication switchboard Communication switchboard Dial switch Digital display Check button Main board Power switch ENC3 switch Table 4-1.2: 100/120 model outdoor unit main PCB switch settings...
Page 32 Mini C Series VRF 50/60Hz Figure 4-1.3: 140/160 model outdoor unit main PCB switches and communication switchboard Digital display Check button and force cooling button Dial switch ENC2/ENC3 Table 4-1.3: 140/160 model outdoor unit main PCB switch settings Switch Switch...
Page 33 Mini C Series VRF 50/60Hz Table 4-1.4: Spot check display table (for all model) DSP1 content Parameters displayed on DSP2 Remarks 0.-- Actual value = value displayed Operating frequency 1.-- Operating mode Refer to Note 1 2.-- Operating fan speed level Refer to Note 2 3.--...
Page 34 Mini C Series VRF 50/60Hz Part 5 Electrical Components and Wiring Diagrams 1 Outdoor Unit Electric Control Box Layout ..........34 2 Outdoor Unit Main PCB ................. 37 3 Wiring Diagrams ..................44...
Page 35 Mini C Series VRF 50/60Hz 1 Outdoor Unit Electric Control Box Layout Figure 5-1.1: 80 model electric control box Main control board Module board Power input and power filter Module board PFC module IPM module DC fan motor control module...
Page 36 Mini C Series VRF 50/60Hz Figure 5-1.2: 100/120 model electric control box Main control board Communication converter board Common mode inductor Main control board PFC module Electric capacitor DC fan port Compressor connecter Switching power supply IPM module Communication converter board...
Page 37 Mini C Series VRF 50/60Hz Figure 5-1.3: 140/160 model electric control box Filter board Main control board Power input terminals Switch power supply DC fan control module IPM module Communication terminals PFC module Filter board Power input Main control board...
Page 38 Mini C Series VRF 50/60Hz 2 Outdoor Unit Main PCB 2.1 Ports Figure 5-1.1: 80 model outdoor unit main PCB ports Notes: 1. Label descriptions are given in Table 5-1.1. Table 5-1.1: 80 model main PCB ports Label in Port code...
Page 39 Mini C Series VRF 50/60Hz Figure 5-1.2: 100/120 model outdoor unit main board ports Table 5-1.2: 100/120 model main board ports Label in Code Content Port voltage Figure 5-1.2 AC power input L ,VLN=220-240VAC 50Hz AC power input N ,VLN=220-240VAC 50Hz...
Page 40 Mini C Series VRF 50/60Hz Figure 5-1.3: 100/120 model outdoor unit Communication converter board PCB Ports Table 5-1.3: 100/120 model communication converter board PCB ports Label in Port code Content Port voltage Figure 5-1.3 R T communication port 2.5-2.7V DC P Q E X Y E communication port（with main board）...
Page 41 Mini C Series VRF 50/60Hz Figure 5-1.4: 140/160 model outdoor unit Communication switchboard PCB Ports Table 5-1.4: 140/160 model communication switchboard PCB ports Label in Port code Content Port voltage Figure 5-1.4 CN502 Power input port AC 220V CN501 Power input port...
Page 42 Mini C Series VRF 50/60Hz Figure 5-1.5: 140/160 model outdoor unit filter board Ports Table 5-1.4: 140/160 model filter board ports Label in Port code Content Port voltage Figure 5-1.5 AC Power Output AC 220V Reserved Relay control/ current sampling output port DC 12V/AC 0-10.4V...
Page 43 Mini C Series VRF 50/60Hz 2.2 Components 2.2.1 LED indicators Table 5-2.1: LED indicators LED1 / LED2/ LED3 Indicator LED indicator function and status Inverter module operating indicator. Continuously on if the compressor is running LED 301 normally and flashing if an inverter module error has occurred Inverter module error indicator.
Page 44 Mini C Series VRF 50/60Hz Indoor heat exchanger pipe (T2/T2B) average temperature (°C) Actual value Total number of IDUs Actual value Number of Operating IDUs Actual value Model Actual value System address Valid at 0~7 Priority mode Refer to note 5...
Page 45 Mini C Series VRF 50/60Hz 3 Wiring Diagrams Figure 5-3.1: 80 model wiring diagram Component code Description Component code Description CH1-CH5 Magnetic ring Relay COMP. Compressor STF1 Four-way valve Electronic expansion valve Compressor top thermostat DCFAN DC fan Outdoor discharge temperature sensor...
Page 46 Mini C Series VRF 50/60Hz Figure 5-3.2: 100/120 model wiring diagram Component code Description Component code Description Rectifier bridge stacking Relay CH1-CH6 Magnetic ring STF1 Four-way valve COMP. Compressor Outdoor heat exchanger temperature sensor AC current transformer Outdoor ambient temperature sensor...
Page 47 Mini C Series VRF 50/60Hz Figure 5-3.3: 140/160 model wiring diagram Component code Description Component code Description 3-slot power supply terminal H-PRO High pressure switch Communication converter board L-PRO Low pressure switch CHI-CH4 Magnetic ring STF1 Four-way valve COMP. Compressor...
Page 48 Mini C Series VRF 50/60Hz...
Page 49 Mini C Series VRF 50/60Hz Part 6 Diagnosis and Troubleshooting 1 Error Code Table ..................49 2 Troubleshooting ..................50...
Page 50 Mini C Series VRF 50/60Hz 1 Error Code Table Table 6-1.1: Error code table Error code Content Note Communication fault between main control board and communicate converter board 100/120 model Abnormal shutdown of compressor inverter module board 80 model Communication fault between outdoor unit and indoor units...
Page 51 Mini C Series VRF 50/60Hz 2 Troubleshooting 2.1 Warning Warning  All electrical work must be carried out by competent and suitably qualified, certified and accredited professionals and in accordance with all applicable legislation (all national, local and other laws, standards, codes, rules, regulations and other legislation that apply in a given situation).
Page 52 Mini C Series VRF 50/60Hz 2.3 E2: Communication error between indoor and outdoor unit (For all models) 2.3.1 Digital display output 2.3.2 Description  Communication error between indoor and outdoor unit.  The system stops running.  Error code displayed on the outdoor unit PCB.
Page 53 Mini C Series VRF 50/60Hz Communication wires are close to a source Remove the source of interference, or of electromagnetic radiation such as add additional shielding to the transformer or strong fluorescent lamp communication wires The length of communication wire is over...
Page 54 Mini C Series VRF 50/60Hz is 71×100W(2.5HP).  If the signal is weak, connect a 120Ω resistor between P and Q of the farthest indoor unit, or connect a 0.5-1.5uF capacitor between P and Q of outdoor unit. Installation refers to Figure 6-2.1: Figure 6-2.1: Indoor unit installation...
Page 55 Mini C Series VRF 50/60Hz 2.4 E4: Temperature sensor (T3/T4) fault (For all models) 2.4.1 Digital display output 2.4.2 Description  Outdoor heat exchanger temperature sensor (T3) error or outdoor ambient temperature sensor (T4) error.  The system stops running.
Page 56 Mini C Series VRF 50/60Hz 2.5 E5: Abnormal power supply voltage (For all models) 2.5.1 Digital display output 2.5.2 Description  Abnormal power supply voltage.  The system stops running.  Error code displayed on the outdoor unit PCB. 2.5.3 Trigger / recover condition ...
Page 57 Mini C Series VRF 50/60Hz 2.6 E6: DC fan motor error; Eb: E6 protection appears 6 times in one hour (For all models) 2.6.1 Digital display output E6 or Eb 2.6.2 Description  E6:DC fan motor error; Eb: E6 protection appears 6 times in one hour ...
Page 58 Mini C Series VRF 50/60Hz 2.7 E7: Discharge temperature sensor (T5) error (only for 80 model) 2.7.1 Digital display output 2.7.2 Description  A compressor discharge pipe temperature sensor (T5) error.  The system stops running.  Error code displayed on the outdoor unit PCB.
Page 59 Mini C Series VRF 50/60Hz 2.8 E9: EEPROM error (For all models) 2.8.1 Digital display output 2.8.2 Description  EEPROM error  The system stops running.  Error code displayed on the outdoor unit PCB. 2.8.3 Trigger / recover condition ...
Page 60 Mini C Series VRF 50/60Hz 2.9 E.9.: Compressor parameters mismatch (For all modes) 2.9.1 Digital display output E.9. 2.9.2 Description  Main control chip detect the power setting number mismatch the model, the unit will display E.9. error.  The system stops running.
Page 61 Mini C Series VRF 50/60Hz 2.10 EF: PFC fault (Only for 100~160 model) 2.10.1 Digital display output 2.10.2 Description  PFC fault protection.  The system stops running.  Error code displayed on the outdoor unit PCB. 2.10.3 Trigger / recover condition ...
Page 62 Mini C Series VRF 50/60Hz 2.11 EH: Refrigerant radiator temperature sensor error (For all models) 2.11.1 Digital display output 2.11.2 Description  Refrigerant radiator temperature TL sensor error.  The system stops running.  Error code displayed on outdoor unit PCB.
Page 63 Mini C Series VRF 50/60Hz 2.12 EP: Outdoor ambient temperature is lower than -5 in cooling operation (For all models) ℃ 2.12.1 Digital display output 2.12.2 Description  Outdoor ambient temperature is lower than -5℃ in cooling operation.  The system stops running.
Page 64 Mini C Series VRF 50/60Hz 2.13 F1: DC bus voltage protection (Only for 100~160 model) 2.13.1 Digital display output 2.13.2 Description  F1 indicates DC bus voltage protection.  The system stops running.  Error code displayed on the outdoor unit PCB.
Page 65 Mini C Series VRF 50/60Hz 2.14 H0: Communicate malfunction between inverter module board and main control board (for all models) 2.14.1 Digital display output 2.14.2 Description  Communicate malfunction between inverter module board and main control board protection.  The system stops running.
Page 66 Mini C Series VRF 50/60Hz 2.15 H7: Number of indoor unit detected is increase or decrease (For all models) 2.15.1 Digital display output 2.15.2 Description  Number of indoor unit detected is increase or decrease protection.  The system stops running.
Page 67 Mini C Series VRF 50/60Hz 2.16 P1: Discharge pipe high pressure protection (for 100~160 model) 2.16.1 Digital display output 2.16.2 Description  Discharge pipe high pressure protection.  The system stops running.  Error code displayed on the outdoor unit PCB.
Page 68 Mini C Series VRF 50/60Hz 2.16.5 Procedure High pressure sensor connection on main Ensure the sensor is connected properly PCB is loose High pressure sensor has short-circuited or Replace the sensor failed Discharge part of the refrigerant. Add oil if...
Page 69 Mini C Series VRF 50/60Hz 2.17 P2: Suction pipe low pressure protection (For all models) 2.17.1 Digital display output 2.17.2 Description  Suction pipe low pressure protection.  The system stops running.  Error code displayed on outdoor unit PCB.
Page 70 Mini C Series VRF 50/60Hz 2.17.5 Procedure the outdoor ambient temperature is too Stop the unit Low pressure sensor connection on main Ensure the sensor is connected properly PCB is loose Low pressure sensor has short-circuited or Replace the sensor...
Page 71 Mini C Series VRF 50/60Hz 2.17 P3: Compressor current protection (For all models) 2.17.6 Digital display output 2.17.7 Description  P3 indicates current protection on compressor.  The system stops running.  Error code displayed on the outdoor unit PCB.
Page 72 Mini C Series VRF 50/60Hz The condenser heat exchange is poor Inspect the system and fix the error The high pressure side is blocked, caused Inspect the system and fix the error by crushed or bent pipe or blocked EXV...
Page 73 Mini C Series VRF 50/60Hz 2.18 P4: Discharge temperature protection (For all models) 2.18.1 Digital display output 2.18.2 Description  Discharge temperature protection.  The system stops running.  Error code displayed on the unit with the error. 2.18.3 Trigger / recover condition ...
Page 74 Mini C Series VRF 50/60Hz 2.18.5 Procedure Discharge pipe temperature sensor Ensure the sensors and switch are connected and/or discharge temperature switch properly connections on main PCB are loose Compressor top temperature sensor and/or discharge pipe temperature Replace the faulty sensor(s)
Page 75 Mini C Series VRF 50/60Hz 2.19 P5: Outdoor heat exchanger temperature protection (For all models) 2.19.1 Digital display output 2.19.2 Description  Outdoor heat exchanger temperature protection.  The system stops running.  Error code displayed on the unit with the error.
Page 76 Mini C Series VRF 50/60Hz 2.19.5 Procedure Outdoor heat exchanger temperature Ensure the sensor is connected properly sensor connection on main PCB is loose Outdoor heat exchanger temperature Replace the sensor sensor has short-circuited or failed Make sure the combination ratio is less than...
Page 77 Mini C Series VRF 50/60Hz 2.20 P8: Typhoon protection (For all models) 2.20.1 Digital display output 2.20.2 Description  P8 indicates strong wind protection.  The system stops running.  Error code displayed on the outdoor unit PCB. 2.20.3 Trigger / recover condition ...
Page 78 Mini C Series VRF 50/60Hz 2.21 PE: Evaporator high temperature protection (For all models) 2.21.1 Digital display output 2.21.2 Description  Evaporator high temperature protection  The system stops running.  Error code displayed on the outdoor unit PCB. 2.21.3 Trigger / recover condition ...
Page 79 Mini C Series VRF 50/60Hz 2.22 PL: Radiator surface high temperature protection (For all models) 2.22.1 Digital display output 2.22.2 Description  Radiator surface high temperature protection.  The system stops running.  Error code displayed on outdoor unit PCB.
Page 80 Mini C Series VRF 50/60Hz 2.23 L0/L4/L5/L8/L9: L category of inverter module protection (L0 for all models, L4/L5/L8/L9 for 100-160 model) 2.23.1 Digital display output L0/L4/L5/L8/L9 2.23.2 Description  Compressor inverter module protection.  The system stops running.  Error code displayed on the outdoor unit PCB.
Page 81 Mini C Series VRF 50/60Hz 2.23.6 L5: Zero speed protection There is abnormal noise of Replace the compressor compressor when startup or running Replace the inverter module 2.23.7 L8 / L9 troubleshooting L8/L9 Reconnect the cables based on Compressor wiring is not properly...
Page 82 Mini C Series VRF 50/60Hz 2.23.8 L1: Procedure Voltage of power supply is 166-265V? Provide normal power supply Check the wiring between main control board and Connect again filter board is correct or not. Repower on and waiting for 10S,and then test the voltage of CN4 port "RL"...
Page 83 Mini C Series VRF 50/60Hz Step 3: Check oil in other compressors in the system  If the oil drained from the faulty compressor is clean, go to Step 6.  If the oil drained from the faulty compressor is spoiled (lightly or heavily), go to Step 4.
Page 84 Ver. 2021-08 HVAC & Building Technologies Division Midea Group Add.: Midea Headquarters Building, 6 Midea Avenue, Shunde, Foshan, Guangdong, China Postal code: 528311 hbt.midea.com / www.midea-group.com Note: Product specifications change from time to time as product improvements and developments are released and may vary from those in this...

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