Midea MV6-252WV2GN1 Service Manual
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Midea MV6-252WV2GN1 Service Manual

Commercial air conditioners
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Manual
MV6-252WV2GN1
MV6-280WV2GN1
MV6-335WV2GN1
MV6-400WV2GN1
MV6-450WV2GN1
MV6-500WV2GN1
Commercial Air Conditioners
Series
MV6-560WV2GN1
MV6-615WV2GN1
MV6-670WV2GN1
MV6-730WV2GN1
MV6-785WV2GN1
MV6-850WV2GN1
MV6-900WV2GN1
R410A

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nutsa
February 21, 2025

the warning: the length from indoor unit to the nearest branch joint should be less than the allowed value what does it mean

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Summary of Contents for Midea MV6-252WV2GN1

  • Page 1 R410A Commercial Air Conditioners Service Manual Series MV6-252WV2GN1 MV6-560WV2GN1 MV6-615WV2GN1 MV6-280WV2GN1 MV6-670WV2GN1 MV6-335WV2GN1 MV6-730WV2GN1 MV6-400WV2GN1 MV6-785WV2GN1 MV6-450WV2GN1 MV6-850WV2GN1 MV6-500WV2GN1 MV6-900WV2GN1...
  • Page 2 V6 VRF 50/60Hz CONTENTS Part 1 General Information ................3 Part 2 Components Layout and Refrigerant Circuits ........11 Part 3 Control ....................33 Part 4 Field Settings ..................49 Part 5 Electrical Components and Wiring Diagrams ........55 Part 6 Diagnosis and Troubleshooting ............69...
  • Page 3 V6 VRF 50/60Hz...
  • Page 4 V6 VRF 50/60Hz Part 1 General Information Indoor and Outdoor Unit Capacities ..........4 External Appearance ................6 Outdoor Unit Combinations ..............8 Combination Ratio ................9...

  • Page 5: Indoor And Outdoor Unit Capacities

    V6 VRF 50/60Hz 1 Indoor and Outdoor Unit Capacities 1.1 Indoor Units 1.1.1 Standard indoor units Table 1-1.1: Standard 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 &...
  • Page 6 V6 VRF 50/60Hz 1.3 Outdoor Units Table 1-1.6: Outdoor unit capacity range Capacity Model Name Combination Type MV6-252WV2GN1 MV6-280WV2GN1 10HP MV6-335WV2GN1 12HP MV6-400WV2GN1 14HP MV6-450WV2GN1 16HP MV6-500WV2GN1 18HP MV6-560WV2GN1 20HP MV6-615WV2GN1 22HP MV6-670WV2GN1 24HP MV6-730WV2GN1 26HP MV6-785WV2GN1 28HP MV6-850WV2GN1 30HP...

  • Page 7: External Appearance

    V6 VRF 50/60Hz 2 External Appearance 2.1 Indoor Units 2.1.1 Standard indoor units Table 1-2.1: Standard 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 Console 2.1.2 Fresh air processing unit...
  • Page 8 V6 VRF 50/60Hz 2.3 Outdoor Units 2.3.1 Single units Table 1-2.4: Single outdoor unit appearance 8/10/12HP 14/16HP 18/20/22HP 24/26/28/30/32HP (with single fan) (with single fan) (with dual fans) (with dual fans) 2.3.2 Combinations of units Table 1-2.5: Combination outdoor unit appearance 34HP 36/38HP 40HP...

  • Page 9: Outdoor Unit Combinations

    V6 VRF 50/60Hz 3 Outdoor Unit Combinations Table 1-3.1: Outdoor unit combinations System capacity Modules Number Outdoor branch of units joint kit 25.2 ● 28.0 ● 33.5 ● 40.0 ● 45.0 ● 50.0 ● 56.0 ● — 61.5 ● 67.0 ●...

  • Page 10: Combination Ratio

    V6 VRF 50/60Hz 4 Combination Ratio Sum of capacity indexes of the indoor units Combination ratio = Capacity index of the outdoor units Table 1-4.1: Indoor and outdoor unit combination ratio limitations Maximum combination ratio Minimum Type Standard indoor Fresh air processing Fresh air processing units and combination ratio units only...
  • Page 11 V6 VRF 50/60Hz...
  • Page 12 V6 VRF 50/60Hz Part 2 Components Layout and Refrigerant Circuits Layout of Functional Components ............12 Piping Diagrams .................. 16 Refrigerant Flow Diagrams ..............22...
  • Page 13 V6 VRF 50/60Hz 1 Layout of Functional Components 8/10/12HP Figure 2-1.1: 8/10/12 layout of functional components Legend Parts name Compressor Temperature sensor for discharge gas High pressure switch High pressure sensor Oil separator Four-way valve Heat exchanger Electronic expansion valve (EXV) Low pressure switch Fan motor Stop valve (liquid side)
  • Page 14 V6 VRF 50/60Hz 14/16HP Figure 2-1.2: 14/16 layout of functional components Legend Parts name Compressor Temperature sensor for discharge gas High pressure switch High pressure sensor Oil separator Four-way valve Heat exchanger Electronic expansion valve (EXV) Low pressure switch Fan motor Stop valve (liquid side) Stop valve (gas side) Plate heat exchanger...
  • Page 15 V6 VRF 50/60Hz 18/20/22HP Figure 2-1.3: 18/20/22 layout of functional components Legend Parts name Compressor Temperature sensor for discharge gas High pressure switch High pressure sensor Oil separator Four-way valve Heat exchanger Electronic expansion valve (EXV) Low pressure switch Fan motor Stop valve (liquid side) Stop valve (gas side) Plate heat exchanger...
  • Page 16 V6 VRF 50/60Hz 24/26/28/30/32HP Figure 2-1.4: 24/26/28/30/32 layout of functional components Legend Parts name Compressor Temperature sensor discharge gas High pressure switch High pressure sensor Oil separator Four-way valve Heat exchanger Electronic expansion valve (EXV) Low pressure switch Fan motor Stop valve (liquid side) Stop valve (gas side) Plate heat exchanger...
  • Page 17 V6 VRF 50/60Hz 2 Piping Diagrams 8/10/12HP Figure 2-2.1: 8/10/12HP piping diagram E S C EXVA EXVC T7C1 Legend Parts name Parts name Compressor Plate heat exchanger Discharge temperature switch Accumulator High pressure switch Heat exchanger cooling electric control box High pressure sensor Heat exchanger temperature sensor Oil separator...
  • Page 18 V6 VRF 50/60Hz 14/16HP Figure 2-2.2: 14/16HP piping diagram EXVA EXVB EXVC T7C1 Legend Parts name Parts name Compressor Accumulator Discharge temperature switch Heat exchanger cooling electric control box High pressure switch Heat exchanger temperature sensor High pressure sensor Outdoor ambient temperature sensor Oil separator Plate heat exchanger inlet temperature sensor Four-way valve...
  • Page 19 V6 VRF 50/60Hz 18/20/22HP Figure 2-2.3: 18/20/22HP piping diagram E S C EXVA EXVB EXVC T7C1 T7C2 Legend Parts name Parts name Compressor Accumulator Discharge temperature switch Heat exchanger cooling electric control box High pressure switch Heat exchanger temperature sensor High pressure sensor Outdoor ambient temperature sensor Oil separator...
  • Page 20 V6 VRF 50/60Hz 24/26/28HP Figure 2-2.4: 24/26/28HP piping diagram EXVA EXVB EXVC T7C1 T7C2 Legend Parts name Parts name Compressor Accumulator Discharge temperature switch Heat exchanger cooling electric control box High pressure switch Heat exchanger temperature sensor High pressure sensor Outdoor ambient temperature sensor Oil separator Plate heat exchanger inlet temperature sensor...
  • Page 21 V6 VRF 50/60Hz 30/32HP Figure 2-2.5: 30/32HP piping diagram EXVA EXVB EXVC T7C1 T7C2 Legend Parts name Parts name Compressor Heat exchanger cooling electric control box Discharge temperature switch Heat exchanger temperature sensor High pressure switch Outdoor ambient temperature sensor High pressure sensor Plate heat exchanger inlet temperature sensor Oil separator...
  • Page 22 V6 VRF 50/60Hz 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. Accumulator: Stores liquid refrigerant and oil to protect compressor from liquid hammering. 3.
  • Page 23 V6 VRF 50/60Hz 3 Refrigerant Flow Diagrams 8/10/12HP Cooling operation Figure 2-3.1: 8/10/12HP refrigerant flow during cooling operation High temperature, high pressure gas High temperature, high pressure liquid Medium temperature, medium pressure gas Unit on Low temperature, low pressure Thermostat on Filter Filter Normal control...
  • Page 24 V6 VRF 50/60Hz Oil return operation in heating mode and defrosting operation Figure 2-3.3: 8/10/12HP refrigerant flow during oil return operation in heating mode and during defrosting operation High temperature, high pressure gas High temperature, high pressure liquid Medium temperature, medium pressure gas Unit on Low temperature, low pressure Thermostat on...
  • Page 25 V6 VRF 50/60Hz 14/16HP Cooling operation Figure 2-3.5: 14/16HP refrigerant flow during cooling operation High temperature, high pressure gas High temperature, high pressure liquid Medium temperature, medium pressure gas Unit on Low temperature, low pressure Thermostat on Filter Filter Normal control E S C Unit on EXVA EXVB...
  • Page 26 V6 VRF 50/60Hz Oil return operation in heating mode and defrosting operation Figure 2-3.7: 14/16HP refrigerant flow during oil return operation in heating mode and during defrosting operation High temperature, high pressure gas High temperature, high pressure liquid Medium temperature, medium pressure gas Unit on Low temperature, low pressure Thermostat on...
  • Page 27 V6 VRF 50/60Hz 18/20/22HP Cooling operation Figure 2-3.9: 18/20/22HP refrigerant flow during cooling operation High temperature, high pressure gas Unit on High temperature, high pressure liquid Thermostat on Medium temperature, medium pressure gas Filter Filter Low temperature, low pressure Normal control Unit on E S C Thermostat on...
  • Page 28 V6 VRF 50/60Hz Oil return operation in heating mode and defrosting operation Figure 2-3.11: 18/20/22HP refrigerant flow during oil return operation in heating mode and during defrosting operation High temperature, high pressure gas Unit on High temperature, high pressure liquid Thermostat on Medium temperature, medium pressure gas Filter...
  • Page 29 V6 VRF 50/60Hz 24/26/28HP Cooling operation Figure 2-3.13: 24/26/28HP refrigerant flow during cooling operation High temperature, high pressure gas Unit on High temperature, high pressure liquid Thermostat on Medium temperature, medium pressure gas Filter Filter Low temperature, low pressure Normal control Unit on E S C Thermostat on...
  • Page 30 V6 VRF 50/60Hz Oil return operation in heating mode and defrosting operation Figure 2-3.15: 24/26/28HP refrigerant flow during oil return operation in heating mode and during defrosting operation High temperature, high pressure gas Unit on High temperature, high pressure liquid Thermostat on Medium temperature, medium pressure gas Filter...
  • Page 31 V6 VRF 50/60Hz 30/32HP Cooling operation Figure 2-3.17: 30/32HP refrigerant flow during cooling operation High temperature, high pressure gas Unit on High temperature, high pressure liquid Thermostat on Medium temperature, medium pressure gas Filter Filter Low temperature, low pressure Normal control Unit on E S C Thermostat on...
  • Page 32 V6 VRF 50/60Hz Oil return operation in heating mode and defrosting operation Figure 2-3.19: 30/32HP refrigerant flow during oil return operation in heating mode and during defrosting operation High temperature, high pressure gas Unit on High temperature, high pressure liquid Thermostat on Medium temperature, medium pressure gas Filter...
  • Page 33 V6 VRF 50/60Hz...

  • Page 34: Table Of Contents

    V6 VRF 50/60Hz Part 3 System Control General Control Scheme Flowchart ............34 Stop Operation ..................35 Standby Control ................... 35 Startup Control ..................36 Normal Operation Control ..............38 Protection Control ................43 Special Control ..................45...

  • Page 35: General Control Scheme Flowchart

    V6 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 activated. Stop operation  Abnormal shutdown  System stops  A unit stops when the load demanded decreases Standby control Special control ...

  • Page 36: Stop Operation

    V6 VRF 50/60Hz 2 Stop Operation The stop operation occurs for one of the three 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. 2.

  • Page 37: Startup Control

    V6 VRF 50/60Hz 4 Startup Control 4.1 Compressor Startup Delay Control In initial startup control, compressor startup is delayed for 12 minutes in order to let the master unit search for the indoor units’ addresses. In restart control (except in oil return operation and defrosting operation), compressor startup is delayed such that a minimum of 7 minutes has elapsed since the compressor stopped, in order to prevent frequent compressor on/off and to equalize the pressure within the refrigerant system.
  • Page 38 V6 VRF 50/60Hz 4.3 Startup Control for Heating Operation Table 3-4.2: Component control during startup in heating mode Wiring Component diagram 8-12HP 14-16HP 18-28HP 30-32HP Control functions and states label Inverter compressor A COMP(A) Controlled according load requirement, ● ● ●...

  • Page 39: Normal Operation Control

    V6 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 Component diagram 8-12HP 14-16HP 18-28HP 30-32HP Control functions and states label Inverter compressor A COMP(A) ● ● ● ●...
  • Page 40 V6 VRF 50/60Hz Table 3-5.2: Component control during heating operation Wiring Component diagram 8-12HP 14-16HP 18-28HP 30-32HP Control functions and states label Inverter compressor A COMP(A) ● ● ● ● Controlled according to load requirement Inverter compressor B COMP(B) ● ●...
  • Page 41 V6 VRF 50/60Hz 5.2 Compressor Output Control The compressor rotation speed is controlled according to the load requirement. Before compressor startup, the outdoor units first estimate the indoor unit load requirement according to the nominal capacity of indoor units currently running, and then correct for ambient temperature.
  • Page 42 V6 VRF 50/60Hz Figure 3-5.3: Compressor priority and rotation – three outdoor units ① No. 1 No. 2 No. 3 No. 1 No. 2 No. 3 No. 4 ① ② No. 3 No. 1 No. 2 No. 3 No. 4 No.
  • Page 43 V6 VRF 50/60Hz  All EXVCs are fully closed.  When some outdoor units are running and some outdoor units are in standby:  EXVCs on running outdoor units are controlled according to temperature different between plate heat exchanger inlet and outlet. EXVCs of units in standby are fully closed. ...

  • Page 44: Protection Control

    V6 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 < 3.2MPa High pressure protection, error code P1 is displayed Notes: : Discharge pressure...
  • Page 45 V6 VRF 50/60Hz high temperatures. It is performed for each compressor and inverter module. Figure 3-6.4: Compressor current protection control Normal operation Current ≥ Current Current < Current Compressor current protection, error code xP3 is displayed Compressor model AA55PHDG –D1YG DC80PHDG –D1YG Current 24.6...

  • Page 46: Special Control

    V6 VRF 50/60Hz 7 Special Control 7.1 Outdoor Unit Duty Cycling In systems with multiple outdoor units, outdoor unit duty cycling is used to prevent compressor burn out due to unbalanced oil levels between outdoor units. Timing of outdoor unit duty cycling: ...
  • Page 47 V6 VRF 50/60Hz Tables 3-7.1 and 3-7.2 show component control during oil return operation in cooling mode. Table 3-7.1: Outdoor unit component control during oil return operation in cooling mode Wiring diagram Component 8-12HP 14-16HP 18-28HP 30-32HP Control functions and states label Inverter compressor A COMP(A)
  • Page 48 V6 VRF 50/60Hz Tables 3-7.3 and 3-7.4 show component control during oil return operation in heating mode. Table 3-7.3: Outdoor unit component control during oil return operation in heating mode Wiring diagram Component 8-12HP 14-16HP 18-28HP 30-32HP Control functions and states label Inverter compressor A COMP(A)
  • Page 49 V6 VRF 50/60Hz 7.3 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 units running time. When the outdoor unit is running in defrosting, the digital display on outdoor main PCB will display “df”.
  • Page 50 V6 VRF 50/60Hz Part 4 Field Settings Outdoor Unit Field Settings..............50...
  • Page 51 V6 VRF 50/60Hz 1 Outdoor Unit Field Settings 1.1 PCB Switches and Switch Settings Figure 4-1.1: Outdoor unit main PCB switches Table 4-1.1: Outdoor unit main PCB switch settings Switch Setting Switch positions Description External Static Pressure is 0Pa (default) External Static Pressure is 20Pa (customize) External Static Pressure is 40Pa (customize) Static pressure...
  • Page 52 V6 VRF 50/60Hz Table 4-1.1: Outdoor unit main PCB switch settings (continued) Switch Setting Switch positions Description Reserved Reserved S6-1 No action (default) Clear indoor unit addresses S6-2 Clear indoor unit addresses Auto addressing (default) Addressing S6-3 mode Manual addressing Reserved Reserved S8-1...
  • Page 53 V6 VRF 50/60Hz 1.2 Modes Set on Main PCB 1.2.1 Priority mode setting Priority mode can only be set on the master unit. When an indoor unit is in mode conflict with the outdoor units the unit displays the mode conflict error. The digital display on indoor main PCB will display error code E0. Figure 4-1.2: Indoor unit digital displays Digital display Digital display...
  • Page 54 V6 VRF 50/60Hz 2. Cooling priority mode: refer to above “1.2. Cooling priority mode” descriptions. 3. VIP priority mode or voting priority mode: The default VIP address is 63, the VIP address also can be changed through menu mode, refer to Part 5, 2.2.3 “Menu mode” Table 5-2.3 “nb8”. If the VIP indoor unit is operating, the outdoor units operate in the mode of the VIP indoor unit.
  • Page 55 V6 VRF 50/60Hz 1.2.2.2 Silent mode setting In silent mode 1 / 2 / 3 and night silent mode, the outdoor fan speed decreases gradually. In super silent mode 1 / 2 / 3 / 4, not only the fan speed decreases gradually, but also the compressor frequency decreases gradually. Table 4-1.3: Silent mode setting Switch Switch positions...
  • Page 56 V6 VRF 50/60Hz Part 5 Electrical Components and Wiring Diagrams 1 Outdoor Unit Electric Control Box Layout ..........56 2 Outdoor Unit Main PCB ................. 58 3 Wiring Diagrams ..................66...
  • Page 57 V6 VRF 50/60Hz 1 Outdoor Unit Electric Control Box Layout 8-16HP Figure 5-1.1: 8-16HP top layer of electric control box Main PCB Filter board Power supply terminals Inductor Communication terminals block Figure 5-1.2: 8-16HP bottom layer of electric control box Inverter module Reactor...
  • Page 58 V6 VRF 50/60Hz 18-32HP Figure 5-1.3: 18-32HP top layer of electric control box Main PCB Filter board Power supply terminals Inductor Communication terminals block Figure 5-1.4: 18-32HP bottom layer of electric control box Inverter Inverter Reactor Reactor module module Fan module Bridge rectifier Bridge rectifier Fan module...
  • Page 59 V6 VRF 50/60Hz 2 Outdoor Unit Main PCB 2.1 Ports Figure 5-2.1: Outdoor unit main PCB ports Notes: Label descriptions are given in Table 5-2.1.
  • Page 60 V6 VRF 50/60Hz Table 5-2.1: Main PCB ports Label in Port code Content Port voltage Figure 5-2.1 High pressure switch and discharge temperature switch(es) CN18 0V or 5V DC connections CN19 Low pressure switch connection 0V or 5V DC Compressor top temperature sensor (single compressor units) or compressor A compressor top temperature sensor 0-5V DC (varying) (dual compressor units) connection...
  • Page 61 V6 VRF 50/60Hz 2.2 Components Layout Figure 5-2.2: Outdoor unit main PCB components Function of buttons SW3 to SW6 Table 5-2.2: Function of buttons SW3 to SW6 Button Function In menu mode: previous and next buttons for menu SW3 (UP) modes.
  • Page 62 V6 VRF 50/60Hz Menu mode Only master unit has the full menu functions, slaves units only have error codes check and cleaning functions. 1. Long press SW5 “MENU” button for 5 seconds to enter menu mode, and the digital display displays “n1”; 2.
  • Page 63 V6 VRF 50/60Hz Menu mode function: Table 5-2.3: Menu mode function Digital display Menu mode Remarks content Debug mode 1 Only available for the master unit (all indoor units running in cooling mode) Only available for the master unit (if all the indoor unit in the system are the 2nd Debug mode 2 generation indoor units, all the indoor units will run in heating mode.
  • Page 64 V6 VRF 50/60Hz How to exit specified menu mode: Table 5-2.4: Exit specified menu mode method: Menu mode Manual exit method Automatic exit method System restart Long press SW6 “OK” button when the digital Debug mode 1 (2) After running 120 minutes Invalid display is not in menu selection state Maintenance mode...
  • Page 65 V6 VRF 50/60Hz Table 5-2.5: System check (continued) DSP1 Parameters displayed on DSP2 Remarks content 34.-- Reserved 35.-- Reserved 36.-- DC voltage A Actual value = value displayed × 10 37.-- DC voltage B Actual value = value displayed × 10 38.-- Reserved 39.--...
  • Page 66 V6 VRF 50/60Hz 3 Compressor Inverter Module Layout Figure 5-3.1: Compressor inverter module components Connect to reactor 3-phase bridge rectifier power output 3-phase bridge rectifier power input LED1 / LED2 Dial switch S7 LED indicators LED1 and LED2 Table 5-3.1: LED indicators LED1 and LED2 Indicator LED indicator function and status Inverter module operating indicator.
  • Page 67 V6 VRF 50/60Hz 4 Wiring Diagrams 8-28HP Figure 5-4.1: 8-28HP wiring diagram CN100 CN30 CN85 CN84 CN83 CN46 CN45 CN44 CN43 L-PRO CN19 CN41 H-PRO CN18 CN47 CN67_1 T7C1 T7C2 H-YL1 EEVA EEVC CN67 CN17 CN8_1 CN28 CN70 CN72 CN66_1 T4 T3 O-FAN EEVB...
  • Page 68 V6 VRF 50/60Hz 30-32HP Figure 5-4.2: 30-32HP wiring diagram CN100 CN85 CN30 CN84 CN83 CN46 CN45 CN44 CN43 L-PRO CN19 CN41 H-PRO CN18 CN47 CN67_1 T7C1 T7C2 H-YL1 EEVA EEVC CN67 CN17 CN8_1 CN70 CN72 CN28 CN66_1 T4 T3 O-FAN EEVB N-ON IC17...
  • Page 69 V6 VRF 50/60Hz...
  • Page 70 V6 VRF 50/60Hz Part 6 Diagnosis and Troubleshooting 1 Error Code Table ..................70 2 Troubleshooting ..................71 3 Appendix to Part 6 ................132...
  • Page 71 V6 VRF 50/60Hz 1 Error Code Table Table 6-1.1: Error code table Error Manual re-start Content Remarks code required Only displayed on the slave unit Communication error between outdoor units with the error Phase sequence error Displayed on the unit with the error Communication error between indoor and master unit Only displayed on the master unit Outdoor heat exchanger temperature sensor (T3) error or...
  • Page 72 V6 VRF 50/60Hz Table 6-1.1: Error code table (continued) Error Manual re-start Content Remarks code required Inverter module temperature protection Displayed on the unit with the error Compressor discharge insufficient superheat protection Displayed on the unit with the error Inverter module protection Displayed on the unit with the error DC bus low voltage protection Displayed on the unit with the error...
  • Page 73 V6 VRF 50/60Hz 2.2 E0: Communication error between outdoor units Digital display output Description  Communication error between outdoor units.  All units stop running.  Error code is only displayed on the slave unit with the error. Trigger / recover condition ...
  • Page 74 V6 VRF 50/60Hz Procedure ODU addresses on switch ENC1 are set Set the ODU addresses correctly incorrectly Ensure the communication wires are Communication wires between ODUs are three-core shielded cable and are not connected properly connected properly Wires between outdoor main PCB and electric control box communication Ensure the wires are connected properly terminals block are loose...
  • Page 75 V6 VRF 50/60Hz 2.3 E1: Phase sequence error Digital display output Description  Phase sequence error.  All units stop running.  Error code is only displayed on the unit with the error. Trigger / recover condition  Trigger condition: Wrong phase connection for 1.6s or phase missing for 48s. ...
  • Page 76 V6 VRF 50/60Hz Procedure The phase sequence of the 3-phase Exchange any two of the 3 phase wires power supply is incrorrect Ensure all supply terminals are securely Some power supply terminals are loose fastened The power supply is abnormal Check the power supply equipment Replace outdoor main PCB Notes:...
  • Page 77 V6 VRF 50/60Hz 2.4 E2: Communication error between indoor and master unit Digital display output Description  Communication error between indoor and master unit.  All units stop running.  Error code is only displayed on the master unit. Trigger / recover condition ...
  • Page 78 V6 VRF 50/60Hz Procedure Communication wires P Q E have short Reconnect the communication wires circuited or disconnected Communication wires P Q E are not Connect the communication wires in a connected in a daisy chain daisy chain IDU power supply is abnormal Ensure normal power supply Wires between outdoor main PCB and electric control box communication...
  • Page 79 V6 VRF 50/60Hz 2.5 E4: Temperature sensor (T3/T4) error Digital display output Description  Outdoor heat exchanger temperature sensor (T3) error or outdoor ambient temperature sensor (T4) error.  All units stop running.  Error code is only displayed on the unit with the error. Trigger / recover condition ...
  • Page 80 V6 VRF 50/60Hz Procedure Temperature sensor connection on main Ensure the sensor is connected properly PCB is loose Temperature sensor has short-circuited Replace the sensor or failed Replace outdoor main PCB Notes: Outdoor ambient temperature sensor (T4) and heat exchanger temperature sensor (T3) connection is port CN1 on the main PCB (labeled 11 in Figure 5-2.1 in Part 5, 2.1 “Ports”).
  • Page 81 V6 VRF 50/60Hz 2.6 E5: Abnormal power supply voltage Digital display output Description  Abnormal power supply voltage.  All units stop running.  Error code is only displayed on the unit with the error. Trigger / recover condition  Trigger condition: Outdoor unit power supply phase voltage < 165V. ...
  • Page 82 V6 VRF 50/60Hz Procedure ODU power supply is abnormal or a Provide normal power supply phase is missing Wires between outdoor main PCB, AC filter boards and electric control box Ensure the wires are connected properly power supply terminals are loose High voltage circuit error has occurred, such as the compressor has malfunctioned...
  • Page 83 V6 VRF 50/60Hz 2.7 E7: Temperature sensor (T7C1/2) error Digital display output Description  A compressor top temperature sensor or discharge pipe temperature sensor (T7C1/2) error.  All units stop running.  Error code is only displayed on the unit with the error. Trigger / recover condition ...
  • Page 84 V6 VRF 50/60Hz Procedure Temperature sensor connection on main Ensure the sensor is connected properly PCB is loose Temperature sensor has short-circuited Replace the sensor or failed Replace outdoor main PCB Notes: Compressor top temperature sensor and discharge pipe temperature sensor connections are ports CN4 and CN5 on the main PCB (labeled 3 and 4, respectively, in Figure 5-2.1 in Part 5, 2.1 “Ports”).
  • Page 85 V6 VRF 50/60Hz 2.8 E8: Outdoor unit address error Digital display output Description  Outdoor unit address error.  All units stop running.  Error code is only displayed on the unit with the error. Trigger / recover condition  Trigger condition: Outdoor unit address is set more than 2. ...
  • Page 86 V6 VRF 50/60Hz Procedure The ODU's address is not in the valid Slave units addresses should be set from range 1 to 2 Replace the outdoor main PCB Notes: The master unit address should be set as 0, slave units addresses should be set from 1 to 2, and the addresses should not be repeated within one system.
  • Page 87 V6 VRF 50/60Hz 2.9 xE9: EEPROM mismatch Digital display output In the error code, 'x' is a placeholder for the compressor system (compressor and related electrical components), with 1 representing compressor system A and 2 representing compressor system B. Description ...
  • Page 88 V6 VRF 50/60Hz Procedure Power off the unit and wait for the digital The outdoor unit was powered on display to turn off before restarting the immediately after being powered off unit Inverter module(75A) change to inverter Type/Mode of inverter module is wrong module(50A) or inverter module(50A) change to inverter module(75A) Replace outdoor main PCB...
  • Page 89 V6 VRF 50/60Hz 2.10 xF1: DC bus voltage error Digital display output 'x' is a placeholder for the compressor system (compressor and related electrical components), with 1 representing compressor system A and 2 representing compressor system B. Description  1F1 indicates compressor A DC bus voltage error; 2F1 indicates compressor B DC bus voltage error. ...
  • Page 90 V6 VRF 50/60Hz Procedure Compressor inverter module Reconnect cables based on wiring loosened wiring diagram Disconnect the power supply Reconnect the reactor and Reactor and DC bus wiring is DC bus wire based on wiring incorrectly diagram Check the power supply The power supply is abnormal equipment Replace the inverter module...
  • Page 91 V6 VRF 50/60Hz 2.11 F3, F5: Temperature sensor (T6B/T6A) error Digital display output Description  F3 indicates plate heat exchanger cooling refrigerant outlet temperature sensor (T6B) error.  F5 indicates plate heat exchanger cooling refrigerant inlet temperature sensor (T6A) error. ...
  • Page 92 V6 VRF 50/60Hz Procedure F3 / F5 Temperature sensor connection on main Ensure the sensor is connected properly PCB is loose Temperature sensor has short-circuited Replace the sensor or failed Replace outdoor main PCB Notes: Plate heat exchanger cooling refrigerant inlet temperature sensor (T6A) and plate heat exchanger cooling refrigerant outlet temperature sensor (T6B) connection are port CN8 and CN8_1 on the main PCB (labeled 10 and 12, respectively, in Figure 5-2.1 in Part 5, 2.1 “Ports”).
  • Page 93 V6 VRF 50/60Hz 2.12 F6: Electronic expansion valve connection error Digital display output In the error code, 'x' is a placeholder for the EXV system, with 1 representing EXVA, 2 representing EXVB, and 3 representing EXVC. Description  Electronic expansion valve connection error. ...
  • Page 94 V6 VRF 50/60Hz Procedure Electronic expansion valve coil Ensure the sensor is connected properly connection on main PCB is loose Electronic expansion valve coil has Replace the sensor malfunctioned Replace outdoor main PCB Notes: Electronic expansion valve coil connections are port CN70, CN71 and CN72 on the main PCB (labeled 18, 19 and 20, respectively, in Figure 5-2.1 in Part 5, 2.1 “Ports”).
  • Page 95 V6 VRF 50/60Hz 2.13 xH0: Communication error Digital display output In the error code, 'x' is a placeholder for the compressor system (compressor and related electrical components), with 1 representing compressor system A and 2 representing compressor system B. Description ...
  • Page 96 V6 VRF 50/60Hz Procedure Reset the compressor inverter module Compressor inverter module address via dial switch S7 on inverter address setting is incorrect module Communication wire from outdoor main PCB CN26 to inverter module CN8/CN9 is Reconnect the communication wire loosen Both LED1 and LED2 on inverter module Check the power supply circuit...
  • Page 97 V6 VRF 50/60Hz Notes: Compressor inverter module address is set through dial switch S7 on the inverter module. The compressor inverter module A/B location refers to the wiring diagram. S7 on inverter module Inverter module address 0 for compressor inverter module A 1 for compressor inverter module B Communication wire from outdoor main PCB CN26 to inverter module CN8/CN9.
  • Page 98 V6 VRF 50/60Hz 2.14 H2, H3: Slave units decreased/increased Digital display output Description  H2 indicates that the number of slave units detected by master unit has decreased.  H3 indicates that the number of slave units detected by master unit has increased. ...
  • Page 99 V6 VRF 50/60Hz Procedure H2 / H3 Some outdoor units in the system are Power on all the outdoor units powered off The power supply is abnormal Check the power supply equipment Troubleshoot as for an E0 error Notes: See “E0 Troubleshooting”.
  • Page 100 V6 VRF 50/60Hz 2.15 xH4: Inverter module protection Digital display output In the error code, 'x' is a placeholder for the compressor system (compressor and related electrical components), with 1 representing compressor system A and 2 representing compressor system B. Description ...
  • Page 101 V6 VRF 50/60Hz The specific error codes xL0, xL1, xL2 and xL4 can also be obtained from the inverter module LED indicators. If an inverter module error has occurred, LED2 is continuously on and LED1 flashes. Figure 6-2.4: LED indicators LED1 and LED2 on inverter module Table 5-3.2: Errors indicated on LED1 LED1 flashing pattern Corresponding error...
  • Page 102 V6 VRF 50/60Hz L0: Inverter module protection Note: 2. The DC bus wire should run from the N_in terminal on the inverter module, through the current sensor (in the direction indicated by the arrow on the current sensor), and end at the N_out terminal on the inverter module. Figure 6-2.5: DC detection wire connection method...
  • Page 103 V6 VRF 50/60Hz L1: DC bus low voltage protection L1 protection Check the power supply The power supply is abnormal equipment No output from bridge rectifier Replace the The DC bus voltage (P, N) is abnormal The reactor performs well reactor Replace the inverter module Note:...
  • Page 104 V6 VRF 50/60Hz L2: DC bus high voltage protection L2 protection The power supply is abnormal Check the power supply equipment The DC bus voltage (P, N)is abnormal Replace the inverter module Note: The normal DC voltage between terminals P and N on inverter module should be 450-650V. When the voltage is higher than 700V, L2 protection will be appeared.
  • Page 105 V6 VRF 50/60Hz L4: MCE error Notes: Compressor inverter module address is set through dial switch S7 on the inverter module. The compressor inverter module A/B location refers to the wiring diagram. S7 on inverter module Inverter module address 0 for compressor inverter module A 1 for compressor inverter module B...
  • Page 106 V6 VRF 50/60Hz L7: Phase sequence error...
  • Page 107 V6 VRF 50/60Hz L8: Compressor frequency variation greater than 15Hz within one second protection L9: Actual compressor frequency differs from target frequency by more than 15Hz protection...
  • Page 108 V6 VRF 50/60Hz Compressor replacement procedure Figure 6-2.8: Draining oil from a compressor Step 1: Remove faulty compressor and remove oil  Remove the faulty compressor from the outdoor unit.  Before removing the oil, shake the compressor so as to not allow impurities to remain settled at the bottom.
  • Page 109 V6 VRF 50/60Hz Step 8: Vacuum drying and refrigerant charging  Once all the compressors and other components have been fully connected, vacuum dry the system and recharge refrigerant. Refer to the V6 Engineering Data Book, Part 3. Figure 6-2.10: Inspecting compressor oil This oil is a little This oil is black yellow, but is clear...
  • Page 110 V6 VRF 50/60Hz Figure 6-2.11: Effects of spoiled compressor oil Worn crankshaft Worn scroll plate Worn scroll plate Normal compressor bearings Seriously worn and damaged bearings Filter blocked by impurities, which leads to abnormal compressor suction...
  • Page 111 V6 VRF 50/60Hz 2.16 H7: Unmatched total number of indoor units Digital display output Description  Number of indoor units detected by master unit not same as number set on main PCB.  All units stop running.  Error code is only displayed on the master unit. Trigger / recover condition ...
  • Page 112 V6 VRF 50/60Hz Procedure Number of indoor units set on main PCB Change the setting on the PCB to be the not same as actual number of indoor same as the actual number of indoor units units Some indoor units are powered off Power on all indoor units After re-starting the ODUs and IDUs and Refer to indoor unit troubleshooting...
  • Page 113 V6 VRF 50/60Hz 2.17 H8: High pressure sensor error Digital display output Description  High pressure sensor error.  All units stop running.  Error code is only displayed on the unit with the error. Trigger / recover condition  Trigger condition: Discharge pressure ≤ 0.3MPa. ...
  • Page 114 V6 VRF 50/60Hz Procedure High pressure sensor connection on main Ensure the sensor is connected properly PCB is loose High pressure sensor has short-circuited Replace the sensor or failed Insufficient refrigerant caused by Add refrigerant and inspect system for refrigerant leakage leaks The low pressure side is blocked, caused Inspect the system and fix the error.
  • Page 115 V6 VRF 50/60Hz 2.18 yHd: Slave unit malfunction Digital display output In the error code, 'y' is a placeholder for the address (1 or 2) of the slave unit with the error. Description  1Hd indicates an error on the slave unit with address 1. ...
  • Page 116 V6 VRF 50/60Hz Procedure Check relevant slave unit...
  • Page 117 V6 VRF 50/60Hz 2.19 P1: Discharge pipe high pressure protection Digital display output Description  Discharge pipe high pressure protection. If the system has a 3-phase protector and the 3-phase protector is connected with the high pressure switch, the system will display P1 protection when initially powered on, and P1 protection will disappear once the system reaches a steady state.
  • Page 118 V6 VRF 50/60Hz … flowchart continued from previous page Discharge part of the refrigerant. Add oil Excess refrigerant if it leaks during discharge Flush all refrigerant then vacuum the System contains air or nitrogen system and recharge the refrigerant. Add oil to the system if it leaks The high pressure side is blocked, caused Inspect the system and fix the error...
  • Page 119 V6 VRF 50/60Hz 2.20 P2, H5: Suction pipe low pressure protection Digital display output Description  Suction pipe low pressure protection. If the system has a 3-phase protector and the 3-phase protector is connected to the low pressure switch, the system will display P2 protection when initially powered on, and P2 protection will disappear once the system reaches a steady state.
  • Page 120 V6 VRF 50/60Hz Procedure P2 / H5 ODU stop valves are closed Open the stop valves Insufficient refrigerant caused by Add refrigerant or inspect the system for refrigerant leakage leaks The low pressure side is blocked, caused Inspect the system and fix the error. If the by crushed or bent pipe, blocked EXV, or filter is blocked by ice, the piping should dirty filter...
  • Page 121 V6 VRF 50/60Hz 2.21 xP3: Compressor current protection Digital display output 'x' is a placeholder for the compressor system (compressor and related electrical components), with 1 representing compressor system A and 2 representing compressor system B. Description  1P3 indicates current protection on compressor A; 2P3 indicates current protection on compressor B. ...
  • Page 122 V6 VRF 50/60Hz … flowchart continued from previous page Discharge part of the refrigerant. Add oil Excess refrigerant if it leaks during discharge Flush all refrigerant then vacuum the System contains air or nitrogen system and recharge refrigerant. Add oil to the system if it leaks The condenser heat exchange is poor Inspect the system and fix the error...
  • Page 123 V6 VRF 50/60Hz 2.22 P4, H6: Discharge temperature protection Digital display output Description  Discharge temperature protection.  All units stop running.  Error code is only displayed on the unit with the error. Trigger / recover condition  Trigger condition: For P4 protection: Discharge temperature (T7C1/2) ≥...
  • Page 124 V6 VRF 50/60Hz … flowchart continued from previous page Insufficient refrigerant caused by Add refrigerant and inspect the system refrigerant leakage for leaks Inspect the system and fix the error. If the The system is blocked, caused by crushed filter is blocked by ice, the piping should or bent pipe, blocked EXV or dirty filter be cleaned Make sure the combination ratio is less...
  • Page 125 V6 VRF 50/60Hz 2.23 P5: Outdoor heat exchanger temperature protection Digital display output Description  Outdoor heat exchanger temperature protection.  All units stop running.  Error code is only displayed on the unit with the error. Trigger / recover condition ...
  • Page 126 V6 VRF 50/60Hz Procedure ODU stop valves are closed Open the stop valves 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 The indoor load is too large than 130%...
  • Page 127 V6 VRF 50/60Hz 2.24 P9, H9: Fan module protection Digital display output Description  Fan module protection.  All units stop running.  Error code is only displayed on the unit with the error. Trigger / recover condition  Trigger condition: For P9 protection: Fan speed is too low.
  • Page 128 V6 VRF 50/60Hz … flowchart continued from previous page Some power wires or communication Ensure power and communication wires wires of fan module are not connected are connected properly properly Remove obstruction or replace the fan The fan motor is blocked or has failed motor The power supply is abnormal Check the power supply equipment...
  • Page 129 V6 VRF 50/60Hz 2.25 PL, C7: Inverter module temperature protection Digital display output 'x' is a placeholder for the compressor system (compressor and related electrical components), with 1 representing compressor system A and 2 representing compressor system B. Description  1PL indicates inverter module A temperature protection. ...
  • Page 130 V6 VRF 50/60Hz Procedure PL / C7 The inverter module heat sink is blocked Clean or replace the heat sink or dirty The screws connecting the heat sink to Tighten the screws and make sure the the inverter module are loose heat sink is well-connected Inverter module temperature sensor Ensure the sensor is connected properly...
  • Page 131 V6 VRF 50/60Hz 2.26 PP: Compressor discharge insufficient superheat protection Digital display output Description  Compressor discharge insufficient superheat protection.  All units stop running.  Error code is only displayed on the unit with the error. Trigger / recover condition ...
  • Page 132 V6 VRF 50/60Hz Procedure Compressor top temperature sensor and/or discharge pipe temperature Ensure the sensors are connected sensor connections on main PCB are properly loose Compressor top temperature sensor and/or discharge pipe temperature Replace the faulty sensor(s) sensor have short circuited or failed Poor heat insulation of compressor top temperature sensor resulting in Ensure sufficient heat insulation for...
  • Page 133 V6 VRF 50/60Hz 3 Appendix to Part 6 3.1 Temperature Sensor Resistance Characteristics Table 6-3.1: Outdoor ambient temperature sensor and outdoor heat exchanger temperature sensor resistance characteristics Temperature Resistance Temperature Resistance Temperature Resistance Temperature Resistance (°C) (kΩ) (°C) (kΩ) (°C) (kΩ) (°C) (kΩ)
  • Page 134 V6 VRF 50/60Hz Table 6-3.2: Compressor top temperature sensor and discharge pipe temperature sensor resistance characteristics Temperature Temperature Temperature Temperature Resistance Resistance Resistance Resistance (kΩ) (kΩ) (kΩ) (kΩ) (°C) (°C) (°C) (°C) 542.7 68.66 13.59 3.702 511.9 65.62 13.11 3.595 483.0 62.73 12.65...
  • Page 135 V6 VRF 50/60Hz Table 6-3.3: Inverter module temperature sensor resistance characteristics Temperature Temperature Temperature Temperature Resistance Resistance Resistance Resistance (kΩ) (kΩ) (kΩ) (kΩ) (°C) (°C) (°C) (°C) 971.4 109.0 19.70 5.000 912.8 103.9 18.97 4.855 858.2 99.02 18.26 4.705 807.3 94.44 17.59 4.566...
  • Page 136 V6 VRF 50/60Hz 3.2 Normal Operating Parameters of Refrigerant System Under the following conditions, the operating parameters given in Tables 6-3.4 and 6-3.5 should be observed:  The master outdoor unit can detect all the indoor units.  The number of indoor units displayed on DSP2 is steady and is equal to the actual number of indoor units installed. ...
  • Page 137 Ver. 2020-08 Commercial Air Conditioner Division Midea Group Add.: Midea Headquarters Building, 6 Midea Avenue, Shunde, Foshan, Guangdong, China Postal code: 528311 cac.midea.com / global.midea.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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