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M-Thermal A Series Split 

Commercial Air Conditioners

R32

Service 
Manual 

 

Midea CAC Confidential

Summary of Contents for HB-A100/CGN8-B

Page 1: ...M Thermal A Series Split Commercial Air Conditioners R32 Service Manual Midea CAC Confidential...

Page 2: ...thermal Split 202004 1 CONTENTS CONTENTS Part 1 General Information 3 Part 2 Component Layout and Refrigerant Circuits 7 Part 3 Control 17 Part 4 Diagnosis and Troubleshooting 31 Midea CAC Confidentia...

Page 3: ...M thermal Split 2 202004 Midea M thermal Split Service Manual Midea CAC Confidential...

Page 4: ...M thermal Split 202004 3 Part 1 General Information Part 1 General Information 1 Unit Capacities 4 2 External Appearance 5 Midea CAC Confidential...

Page 5: ...full model names can be obtained by substituting the asterisk in the model name format given in the left hand column of the table above with the shortened model names given in the table For example th...

Page 6: ...arance 2 1 Outdoor Unit Appearance Table 1 2 1 Outdoor unit appearance MHA V4 6 W D2N8 B MHA V8 10 12 14 16 W D2N8 MHA V12 14 16 W D2RN8 2 2 Hydronic Box Appearance Table 1 2 2 Hydronic box appearance...

Page 7: ...M thermal Split 6 202004 Midea M thermal Split Service Manual Midea CAC Confidential...

Page 8: ...art 2 Component Layout and Refrigerant Circuits Part 2 Component Layout and Refrigerant Circuits 1 Layout of Functional Components 8 2 Piping Diagrams 13 3 Refrigerant Flow Diagrams 15 202004 7 Midea...

Page 9: ...rmal Split Service Manual 1 Layout of Functional Components 1 1 Outdoor Unit Layout MHA V4W D2N8 B MHA V6W D2N8 B Figure 2 1 1 MHA V4 6 W D2N8 B top view Figure 2 1 2 MHA V4 6 W D2N8 B front view 8 20...

Page 10: ...mal Split Part 2 Component Layout and Refrigerant Circuits MHA V8W D2N8 B MHA V10W D2N8 B Figure 2 1 3 MHA V8 10 W D2N8 B top view Figure 2 1 4 MHA V8 10 W D2N8 B front view 202004 9 Midea CAC Confide...

Page 11: ...it Midea M thermal Split Service Manual MHA V12W D2N8 B MHA V14W D2N8 B MHA V16W D2N8 B Figure 2 1 5 MHA V12 14 16 W D2N8 B top view Figure 2 1 6 MHA V12 14 16 W D2N8 B front view 10 202004 Midea CAC...

Page 12: ...2 Component Layout and Refrigerant Circuits MHA V12W D2RN8 B MHA V14W D2RN8 B MHA V16W D2RN8 B Figure 2 1 7 MHA V12 14 16 W D2RN8 B top view Figure 2 1 8 MHA V12 14 16 W D2RN8 B front view 202004 11 M...

Page 13: ...Manual 1 2 Hydronic Box Layout Figure 2 1 9 HB A60 100 160 CGN8 B oblique view Electric control box Expansion vessel Manometer Safety valve Air purge valve Water flow switch Water side heat exchanger...

Page 14: ...V Controls refrigerant flow and reduces refrigerant pressure 2 Four way valve Controls refrigerant flow direction Closed in cooling mode and open in heating mode When closed the air side heat exchange...

Page 15: ...oves air from the water circuit 2 Safety valve Prevents excessive water pressure by opening at 43 5 psi 3 bar and discharging water from the water circuit 3 Expansion vessel Balances water system pres...

Page 16: ...sure switch Low pressure switch Air side heat exchanger 4 way valve High temperature high pressure gas High temperature high pressure liquid Low temperature low pressure Electronic expansion valve cap...

Page 17: ...M thermal Split Midea M thermal Split Service Manual 16 202004 Midea CAC Confidential...

Page 18: ...ntrol Part 3 Control 1 Stop Operation 18 2 Standby Control 18 3 Startup Control 19 4 Normal Operation Control 22 5 Protection Control 23 6 Special Control 26 7 Role of Temperature Sensors in Control F...

Page 19: ...d to prevent refrigerant from mixing with compressor oil when the compressors are stopped The crankcase heater is controlled according to outdoor ambient temperature and the compressor on off state Wh...

Page 20: ...tartup follows one of two startup programs until the target rotation speed is reached Refer to Figure 3 3 1 Figure 3 3 2 Figure 3 3 1 MHA V4 6 W D2N8 B compressor startup program 1 when ambient temper...

Page 21: ...32rps 42rps 56rps 66rps 70rps 40s 90s 60s 40s 40s 240s 82rps 240s 36rps 90s Notes 1 Once the first 40 second stage of the program is complete the program proceeds to the subsequent stages in a step by...

Page 22: ...1 DC fan motor FAN Fan run at maximum speed 2 Electronic expansion valve EXV Position steps from 0 fully closed to 480 fully open controlled according to outdoor ambient temperature discharge temperat...

Page 23: ...then runs the appropriate compressor startup program Refer to Part 3 3 2 Compressor Startup Program Once the startup program is complete the compressor runs at the target rotation speed 4 3 Compresso...

Page 24: ...protects the compressor from transient spikes in pressure Figure 3 5 1 High pressure protection control Notes 1 Pc Discharge pressure When the discharge pressure rises above 4 3MPa the system displays...

Page 25: ...the unit stops running When the discharge temperature is higher than suction temperature the compressor enters re start control 5 4 Compressor Current Protection Control This control protects the comp...

Page 26: ...pm or more for more than 3 minutes Outdoor ambient temperature is below 4 C and actual fan speed differs from target fan speed by 300rpm or more for more than 3 minutes Actual fan speed is less than 1...

Page 27: ...abel 4 16kW Control functions and states Inverter compressor COMP Runs at oil return operation rotation speed DC fan motor FAN Controlled according to heating mode Electronic expansion valve EXV 304 s...

Page 28: ...temperature of each zone separately thus different type radiator will operate at its optimal temperature and water pump cycle time will be reduced to save energy Cooling mode In two zones control for...

Page 29: ...water whilst heat pump runs heat mode cooling which can reduce the host selection and the initial investment 6 8 USB data transfer Convenient program upgrade No need to carry any other heavy equipment...

Page 30: ...erature Sensors in Control Functions Figure 3 7 1 Location of the temperature sensors on M thermal Split systems Notes 1 The names and functions of the temperature sensors labelled 1 to 11 in this fig...

Page 31: ...outlet temperature sensor T3 5 Water side heat exchanger refrigerant outlet gas pipe temperature sensor T2B 6 Water side heat exchanger refrigerant outlet liquid pipe temperature sensor T2 7 Water si...

Page 32: ...M thermal Split 202004 31 Part 4 Diagnosis and Troubleshooting 1 Electric Control Box Layout 32 2 PCBs 35 3 Error Code Table 49 4 Troubleshooting 51 5 Appendix to Part 4 107 Midea CAC Confidential...

Page 33: ...Layout 1 1 Outdoor Unit Electric Control Box Layout Figure 4 1 1 MHA V4 6 W D2N8 B electric control box Main PCB Inverter module Figure 4 1 2 MHA V8 10 W D2N8 B electric control box Main PCB Inverter...

Page 34: ...Split 202004 33 Main PCB Inverter module Figure 4 1 4 MHA V12 14 16 W D2RN8 B electric control box Main PCB Inverter module Main Power Electric Reactor Filter board DCFAN Electric Reactor Midea CAC Co...

Page 35: ...M thermal Split 34 202004 Midea M thermal Split Service Manual 1 2 Hydronic Box Electric Control Box Layout Figure 4 1 5 HB A60 100 160 CGN8 B Main control board Midea CAC Confidential...

Page 36: ...are shown in Figures 4 1 1 to Figure 4 1 4 in Part 4 1 1 Outdoor Unit Electric Control Box Layout The locations of each PCB in the hydronic box electric control box are shown in Figures 4 1 5 in Part...

Page 37: ...rmostat cooling mode CL Power port for room thermostat COM 18 CN35 Port for smart grid grid signal photovoltaic signal 19 CN36 Port for remote switch temperature board 20 CN19 Communicate port between...

Page 38: ...3 Main PCBs for Refrigerant System Inverter Module Figure 4 2 2 MHA V4 6 8 10 W D2N8 B outdoor unit main PCB for refrigerant system 4 5 6 7 8 9 10 3 2 1 11 12 13 14 15 16 17 18 19 27 26 25 24 23 22 2...

Page 39: ...nput port for live wire 12 CN9 Port for outdoor ambient temp sensor and condenser temp sensor 13 CN24 Input port for 12V 9V 14 CN1 Port for suction temp sensor 15 CN8 Port for discharge temp sensor 16...

Page 40: ...thermal Split 202004 39 Figure 4 2 3 MHA V12 14 16 W D2N8 B outdoor unit main PCB for refrigerant system 4 5 6 7 8 9 10 3 2 1 11 12 13 14 15 16 17 18 19 27 26 25 24 23 22 21 20 Midea CAC Confidential...

Page 41: ...nput port for live wire 12 CN9 Port for outdoor ambient temp sensor and condenser temp sensor 13 CN24 Input port for 12V 9V 14 CN1 Port for suction temp sensor 15 CN8 Port for discharge temp sensor 16...

Page 42: ...mal Split 202004 41 Figure 4 2 4 MHA V12 14 16 W D2RN8 B outdoor unit main PCB for refrigerant system 1 2 3 4 5 6 7 8 30 29 9 10 11 12 13 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 Midea CAC Confide...

Page 43: ...cation with main PCB for invert module board 13 CN6 Port for pressure sensor 14 CN36 Port for communication with main PCB for refrigerant system 15 CN5 Port for temp sensor Th 16 CN8 Port for temp sen...

Page 44: ...M thermal Split 202004 43 Figure 4 2 5 MHA V4 6 8 10 W D2N8 B outdoor unit inverter module For 4 6kW model 1 2 3 8 7 4 5 6 9 For 8 10kW model 1 2 3 8 7 4 5 6 9 Midea CAC Confidential...

Page 45: ...5 Code Content 1 U Compressor connection port U 2 V Compressor connection port V 3 W Compressor connection port W 4 CN20 Output port for 12V 9V 5 CN19 Port for fan 6 CN32 Port for communication with m...

Page 46: ...6 Code Content 1 U Compressor connection port U 2 V Compressor connection port V 3 W Compressor connection port W 4 CN19 Port for fan 5 CN20 Output port for 12V 9V 6 CN32 Port for communication with m...

Page 47: ...ut port for 15V 2 CN19 Compressor connection port W 3 CN18 Compressor connection port V 4 CN17 Compressor connection port U 5 CN15 Power Input port L3 6 CN7 Power Input port L2 7 CN5 Input port P_out...

Page 48: ...01 Power supply L2 2 CN200 Power supply L3 3 CN203 Power supply N 4 CN212 Power supply port of 310VDC 5 CN211 Reserved 6 CN213 Port for FAN Reactor 7 CN214 Power supply port for Inverter module 8 PE3...

Page 49: ...tion code Error or protection code 2 5 DIP switch setting and Modbus function Modbus function will be available in 2020 5 30 The rotating coded switch S3 0 F on the main control board of hydraulic mod...

Page 50: ...water inlet temperature sensor error Sensor Tw_in EE 15 Hydronic box EEPROM error F1 116 DC generatrix voltage is too low H0 39 Communication error between outdoor unit main control chip and hydronic...

Page 51: ...ffers from target frequency by more than 15Hz protection Pb 31 Water side heat exchanger anti freeze protection Pd 33 High temperature protection of refrigerant outlet temperature of condenser in cool...

Page 52: ...ce with all applicable legislation all national local and other laws standards codes rules regulations and other legislation that apply in a given situation Power off the outdoor units before connecti...

Page 53: ...s E8 has displayed 3 times When an E0 error occurs a manual system restart is required before the system can resume operation M thermal Split stops running Error code is displayed on hydronic box main...

Page 54: ...increase its speed No Water flow switch is damaged Yes Replace the water flow switch No Internal circulator pump can t work Yes Turn off the power check the wire in the pump Once that is done the pum...

Page 55: ...n 4 3 2 Phase sequence error Only applies to 3 phase models M thermal Split stops running Error code is displayed on outdoor unit main PCB and user interface Possible causes 4 3 3 Power supply phases...

Page 56: ...sequence is inverted the compressor will operate inversely If the wiring connection of each outdoor unit is in A B C phase sequence and multiple units are connected the current difference between C p...

Page 57: ...is displayed on hydronic box main PCB and user interface Possible causes 4 4 3 Communication wires between hydronic box and user interface not connected properly Communication wiring X Y E terminals...

Page 58: ...high voltage 220V or higher wires Yes Ensure the communication wires and high voltage wires are separated No Communication wires are close to a source of electromagnetic radiation such as transformer...

Page 59: ...ror Ed indicates a water side heat exchanger water inlet temperature sensor error HA indicates a water side heat exchanger water outlet temperature sensor error H5 indicates a room temperature sensor...

Page 60: ...CB for Hydronic System Circuit 2 water outlet temperature sensor connection is port CN15 on the hydronic box main PCB labeled 14 in Figure 4 2 1 in Part4 2 2 Main PCB for Hydronic System Room temperat...

Page 61: ...e sensor error E6 indicates an outdoor ambient temperature sensor error E9 indicates a suction pipe temperature sensor error EA indicates a discharge temperature sensor error M thermal Split stops run...

Page 62: ...tem main PCB labeled 15 in Figure 4 2 2 Main PCBs for Refrigerant System Inverter Module 8 on the MHA V12 14 16 W D2N8 B outdoor unit refrigerant system main PCB labeled 15 in Figure 4 2 3 Main PCBs f...

Page 63: ...er interface Possible causes 4 7 3 Hydronic box main PCB EEPROM is not connected properly Hydronic box main PCB damaged Procedure 4 7 4 EE Hydronic box main PCB EEPROM1 is not connected properly Yes E...

Page 64: ...PCB and user interface Possible causes 4 8 3 The DC generatrix voltage is too low Procedure 4 8 4 F1 Power supply is abnormal Yes Provide normal power No LED on the Inverter Modules is lighting Yes Vo...

Page 65: ...connected properly Yes Ensure the EEPROM is connected properly No Replace outdoor unit invert module Notes 1 Outdoor unit invert module EEPROM is designated IC320 on the MHA V4 6 8 10 W D2N8 B outdoo...

Page 66: ...and hydronic box M thermal Split stops running Error code is displayed on hydronic box main PCB outdoor unit main PCB and user interface Possible causes 4 10 3 Power supply abnormal Transformer malfun...

Page 67: ...on wires P Q E between main control board of outdoor unit and hydraulic module have short circuited disconnected or misconnected Yes Reconnect the communication wires No Replace outdoor unit main PCB...

Page 68: ...B or inverter driven module damaged Procedure 4 11 4 H1 LED on the main control board of outdoor unit and inverter module are light Yes LED is not light the board is damaged or have short circuit No C...

Page 69: ...hen HH error occurs a manual system restart is required before the system can resume operation The cause of HH error should be addressed promptly in order to avoid system damage M thermal Split stops...

Page 70: ...iring Diagrams 2 Measure the voltage between the DC fan motor power supply wires The normal voltage is 15V when the unit is in standby If the voltage is significantly different from 15V the IPM module...

Page 71: ...rmal Split stops running Error code is displayed on outdoor unit main PCB and user interface Possible causes 4 13 3 Power supply voltage not within 90 110 of rated voltage Outdoor unit main PCB is dam...

Page 72: ...outdoor unit main PCB Notes 1 Measure the resistance among the three terminals of the pressure sensor If the resistance is of the order of mega Ohms or infinite the pressure sensor has failed The pres...

Page 73: ...unning When the pressure rises above 0 3MPa P0 is removed and normal operation resumes HP indicates Pe 0 6Mpa occurred 3 times in an hour Error code is displayed on outdoor unit main PCB and user inte...

Page 74: ...ck for insufficient refrigerant An insufficiency of refrigerant causes compressor discharge temperature to be higher than normal discharge and suction pressures to be lower than normal and compressor...

Page 75: ...ection and M thermal Split stops running When the discharge pressure falls below 3 6MPa P1 is removed and normal operation resumes Error code is displayed on outdoor unit main PCB and user interface P...

Page 76: ...V12 14 16 W D2N8 B outdoor unit refrigerant system main PCB labeled 16 in Figure 4 2 3 in Part 4 2 3 Main PCB for Refrigerant System Inverter Module port CN31 on the MHA V12 14 16 W D2RN8 B outdoor u...

Page 77: ...16kW single phase model 30A 12 14 16kW three phase model 14A the system displays P3 protection and M thermal Split stops running When the current returns to the normal range P3 is removed and normal o...

Page 78: ...s and water flow switch for dirt blockages In cooling mode check air side heat exchanger fan and air outlets for dirt blockages 2 High pressure side blockage causes discharge temperature to be higher...

Page 79: ...re rises above 115 C the system displays P4 protection and M thermal Split stops running When the discharge temperature falls below 95 C P4 is removed and normal operation resumes Error code is displa...

Page 80: ...CB is loose4 Yes Ensure the pressure switch is connected properly No Pressure sensor has short circuited or failed5 Yes Replace the pressure sensor No The high pressure side is blocked caused by crush...

Page 81: ...unctional Components and to Table 5 5 1 or 5 5 2 in Part 5 5 1 4 High pressure switch connection is port CN13 on the MHA V4 6 8 10 W D2N8 B outdoor unit refrigerant system main PCB labeled 16 in Figur...

Page 82: ...exchanger water inlet and water outlet temperatures protection M thermal Split stops running Error code is displayed on hydronic box main PCB and user interface Possible causes 4 19 3 Temperature sen...

Page 83: ...and fix the error No Replace hydronic box main PCB Notes 1 Water side heat exchanger water inlet temperature sensor and water side heat exchanger water outlet temperature sensor connections are port C...

Page 84: ...o speed protection Excessive compressor frequency variation Actual compressor frequency differs from target frequency High pressure protection PED board self checking fail Specific error codes for inv...

Page 85: ...y more than 15Hz protection Table 4 4 3 Errors indicated on LED single phase 4 10kW LED1 flashing pattern GREEN LED2 is always on RED Corresponding error Flashes 3 times and stops for 1 second then re...

Page 86: ...damaged1 Yes Replace the inverter module2 Notes 1 Measure the resistance between each of U V and W and each of P and N on the inverter module All the resistances should be infinite If any of them are...

Page 87: ...s as indicated by the labels on the compressor 2 Measure the resistance between each of U V and W and each of P and N on the inverter module All the resistances should be infinite If any of them are n...

Page 88: ...Replace the inverter module3 Notes 1 Refer to Figure 4 4 2 2 Use clip on ammeter to measure the compressor current if the current is normal indicates the inverter module is failed if the current is a...

Page 89: ...ion 1 L1 or L2 error appears immediately after the outdoor unit is powered on L1 L2 Power supply is abnormal Yes Re start the unit once the power supply has returned to normal No Replace the inverter...

Page 90: ...Figure 4 4 2 Figure 4 4 4 Relay location of main PCB for refrigerant system Single phase 4 6 8 10kW unit Single phase 12 14 16kW unit Relay L5 L8 L9 troubleshooting 4 20 8 L5 L8 L9 The wire is not co...

Page 91: ...ent protection Zero speed protection Excessive compressor frequency variation Actual compressor frequency differs from target frequency High pressure protection Contactor stuck or 908 self checking fa...

Page 92: ...es 17 times and stops for 1 second then repeats L8 Compressor frequency variation greater than 15Hz within one second protection L9 Actual compressor frequency differs from target frequency by more th...

Page 93: ...B the communication port between refrigerant system main control board for refrigerant system inverter module is port CN36 on refrigerant system main control board for refrigerant system port CN8 on...

Page 94: ...e main PCB Notes 1 The DC bus wire should run from the N 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 termi...

Page 95: ...s 1 Connect the U V W wire from the inverter module to the correct compressor terminals as indicated by the labels on the compressor 2 Measure the voltage between each of W W V V U U and GND when the...

Page 96: ...compressor No Replace the inverter module2 Notes 1 When replacing an inverter module a layer of thermally conductive silica gel should be painted on the IPM module on the reverse side of the inverter...

Page 97: ...ately after the outdoor unit is powered on L1 L2 P N 15V wire on refrigerant system main PCB is not connected properly1 Yes Ensure P N 15V wire is connected properly No Voltage between N and 15 is abn...

Page 98: ...obe on the DC power output negative terminal terminal 5 and put the black probe onto each of the AC power input terminals terminals 1 2 and 3 in turn The voltage between terminal 5 and each of termina...

Page 99: ...60rps L4 Compressor is over current2 Yes Replace the compressor No Replace the inverter PCB Notes 1 Re start the unit use clip on ammeter to measure the compressor current if the current is normal in...

Page 100: ...econds the system displays Pd protection and M Thermal Split stops running When the air side heat exchanger refrigerant outlet temperature returns drops below 55 C Pd is removed and normal operation r...

Page 101: ...e MHA V4 6 8 10 W D2N8 B outdoor unit refrigerant system main PCB labeled 12 in Figure 4 2 2 in Part4 2 3 Main PCB for Refrigerant System Inverter Module port CN9 on the MHA V12 14 16 W D2N8 B outdoor...

Page 102: ...er than outlet temperature in heating mode M thermal Split stops running Error code is displayed on hydronic box main PCB and user interface Hb indicates PP has displayed 3 times Possible causes 4 23...

Page 103: ...xchanger water inlet temperature sensor and water side heat exchanger water outlet temperature sensor connections are port CN6 on the hydronic box main PCB labeled 10 in Figure 4 2 1 in Part4 2 2 Main...

Page 104: ...running Error code is displayed on hydronic box main PCB and user interface Possible causes 4 24 3 Power supply voltage of the unit is low The space between the units is too narrow for heat exchanger...

Page 105: ...low Yes There is air in system or pump head is not enough Release the air and reselect the pump No Water outlet temp sensor1 is loosen or broken Yes Reconnect it or change a new one Notes 1 Water sid...

Page 106: ...display output 4 25 1 Description 4 25 2 PED PCB failure M thermal Split stops running Error code is displayed on hydronic box main PCB and user interface Possible causes 4 25 3 Power supply problem...

Page 107: ...erve whether it can be recovered Yes Increase the power voltage to the required range No PED1 board broken Yes Replace PED PCB and power on again No IPM module broken Yes Replace IPM module and power...

Page 108: ...water inlet temperature sensor or backup electric heater outlet water temperature sensor loose2 Yes Ensure the temperature sensor is connected properly No Water side heat exchanger water outlet tempe...

Page 109: ...23 10 971 63 2 102 103 0 558 16 84 278 24 10 473 64 2 026 104 0 542 15 79 521 25 10 65 1 953 105 0 527 14 75 059 26 9 551 66 1 883 13 70 873 27 9 125 67 1 816 12 66 943 28 8 721 68 1 752 11 63 252 29...

Page 110: ...38 31 62 78 7 321 118 2 233 1 190 5 39 30 36 79 7 086 119 2 174 0 180 9 40 29 15 80 6 859 120 2 117 1 171 9 41 28 00 81 6 641 121 2 061 2 163 3 42 26 90 82 6 430 122 2 007 3 155 2 43 25 86 83 6 228 12...

Page 111: ...103 2 9960 16 379 69 24 51 396 64 10 526 104 2 9096 15 358 83 25 49 165 65 10 161 105 2 8262 14 339 24 26 47 043 66 9 8105 13 320 85 27 45 025 67 9 4736 12 303 56 28 43 104 68 9 1498 11 287 33 29 41 2...

Page 112: ...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 document GD MIDEA Heating Venti...

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