Midea SMK-60/CGN8 Service Manual Download Page 1

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M-Thermal Split Series

Commercial Air Conditioners

R32

Service
Manual

Midea CAC Confidential

Summary of Contents for SMK-60/CGN8

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

Page 2: ...Thermal Split 201909 1 CONTENTS CONTENTS Part 1 General Information 3 Part 2 Component Layout and Refrigerant Circuits 7 Part 3 Control 15 Part 4 Diagnosis and Troubleshooting 28 Midea CAC Confidentia...

Page 3: ...M Thermal Split 2 201909 Midea M Thermal Split Service Manual Midea CAC Confidential...

Page 4: ...M Thermal Split 201909 3 Part 1 General Information Part 1 General Information 1 Unit Capacities 4 2 External Appearance 5 Midea CAC Confidential...

Page 5: ...The 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 examp...

Page 6: ...nformation 2 External Appearance 2 1 Outdoor Unit Appearance Table 1 2 1 Outdoor unit appearance MHA V4 6 W D2N8 MHA V8 10 W D2N8 2 2 Hydronic Box Appearance Table 1 2 2 Hydronic box appearance SMK 60...

Page 7: ...M Thermal Split 6 201909 Midea M Thermal Split Service Manual Midea CAC Confidential...

Page 8: ...01909 7 Part 2 Component Layout and Refrigerant Circuits Part 2 Component Layout and Refrigerant Circuits 1 Layout of Functional Components 8 2 Piping Diagrams 11 3 Refrigerant Flow Diagrams 13 Midea...

Page 9: ...9 Midea M Thermal Split Service Manual 1 Layout of Functional Components 1 1 Outdoor Unit Layout MHA V4W D2N8 MHA V6W D2N8 Figure 2 1 1 MHA V4 6 W D2N8 top view Figure 2 1 2 MHA V4 6 W D2N8 front view...

Page 10: ...Thermal Split 201909 9 Part 2 Component Layout and Refrigerant Circuits MHA V8W D2N8 MHA V10W D2N8 Figure 2 1 3 MHA V8 10 W D2N8 top view Figure 2 1 4 MHA V8 10 W D2N8 front view Midea CAC Confidentia...

Page 11: ...t Service Manual 1 2 Hydronic Box Layout Figure 2 1 5 SMK 60 CGN8 SMK 80 CGN8 oblique view Air purge valve Expansion vessel Safety valve Water flow switch Water pump Manometer Water side heat exchange...

Page 12: ...lary 6 Filter 14 Solenoid valve Key components 1 Electronic expansion valve EXV Controls refrigerant flow and reduces refrigerant pressure 2 Four way valve Controls refrigerant flow direction Closed i...

Page 13: ...ge valve Automatically removes 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...

Page 14: ...t Flow Diagrams Heating and domestic hot water operation Figure 2 3 1 Refrigerant flow during heating or domestic hot water operation Cooling and defrosting operation Figure 2 3 2 Refrigerant flow dur...

Page 15: ...M Thermal Split 14 201909 Midea M Thermal Split Service Manual Midea CAC Confidential...

Page 16: ...ntrol Part 3 Control 1 Stop Operation 16 2 Standby Control 16 3 Startup Control 17 4 Normal Operation Control 18 5 Protection Control 20 6 Special Control 23 7 Role of Temperature Sensors in Control F...

Page 17: ...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 18: ...rtup 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 8 10 W D2N8 compressor startup program1 when ambient temper...

Page 19: ...omponent Wiring diagram label 4 10kW Control functions and states Inverter compressor COMP Compressor startup program selected according to ambient temperature1 DC fan motor FAN Fan run at maximum spe...

Page 20: ...essors used on 4 10kW models in rotations per second rps is one third of the frequency in Hz of the electrical input to the compressor motor The frequency of the electrical input to the compressor mot...

Page 21: ...protection control Notes 1 Pc Discharge pressure When the discharge pressure rises above 4 2MPa the system displays P1 protection and the unit stops running When the discharge pressure drops below 3 2...

Page 22: ...lays EA protection and the unit stops running When the discharge temperature rises to 27 C or higher the compressor enters re start control 5 4 Compressor Current Protection Control This control prote...

Page 23: ...han 150rpm for more than 20 seconds When DC fan motor protection control occurs the system displays the H6 error code and the unit stops running After 3 minutes the unit restarts automatically When H6...

Page 24: ...ration in heating and DHW modes Component Wiring diagram label 4 10kW Control functions and states Inverter compressor COMP Runs at oil return operation rotation speed DC fan motor FAN Controlled acco...

Page 25: ...electric heater TBH On 6 5 Two zones control1 Two zones control function is used to control temperature of each zone separately thus different type radiator will operate at its optimal temperature and...

Page 26: ...the setting temperature will be changed to 70 automatically and the TBH operate as below T5 69 the TBH is on T5 70 the TBH is off The unit operate in cooling heating mode as the normal logic Common el...

Page 27: ...tions 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 figure are detailed in Table 3 7 1...

Page 28: ...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 side heat...

Page 29: ...28 201909 Midea M Thermal Split Service Manual Part 4 Diagnosis and Troubleshooting 1 Electric Control Box Layout 29 2 PCBs 31 3 Error Code Table 39 4 Troubleshooting 41 5 Appendix to Part 4 82 Midea...

Page 30: ...al Split 201909 29 1 Electric Control Box Layout 1 1 Outdoor Unit Electric Control Box Layout Figure 4 1 1 MHA V4 6 8 10 W D2N8 electric control box Main PCB Inverter module Capacitor Midea CAC Confid...

Page 31: ...idea M Thermal Split Service Manual 1 2 Hydronic Box Electric Control Box Layout Figure 4 1 2 SMK 60 80 CGN8 Main PCB Transformer Communication terminal blocks Lighting filter board Power supply termi...

Page 32: ...1 1 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 2 in Part 4 1 2 Hydronic Box Electric Control Box...

Page 33: ...N16 Port for temperature sensor Ta room temp 15 CN17 Port for internal pump 16 S1 S2 Dip switch 17 CN34 Output port for deforst 18 CN40 Port for anti freeze eletric heating tape internal 19 CN41 Port...

Page 34: ...ystem Inverter Module Figure 4 2 2 MHA V4 6 8 10 W D2N8 outdoor unit main PCB for refrigerant system1 1 2 3 4 5 6 29 28 27 7 8 9 10 11 12 13 14 15 26 25 24 23 22 21 30 20 19 18 17 16 Notes 1 Label des...

Page 35: ...p temp sensor 12 CN9 Port for outdoor ambient temp sensor and condenser temp sensor 13 CN1 Port for Th temp sensor 14 CN14 Port for TF temp sensor 15 CN4 Port for pressure sensor 16 CN2 Reserved 17 CN...

Page 36: ...r unit inverter module Label in Figure 4 2 3 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 9 9V CN20 5 CN19...

Page 37: ...essor frequency restriction by Discharge temperature 7 Compressor frequency restriction by pressure 6 T3 Condenser temperature C When no decimal point is displayed Temperature is 9 C Actual value valu...

Page 38: ...temperature C When no decimal point is displayed Temperature is 9 C Actual value value displayed When decimal point is displayed between the two digits Temperature is 10 C Actual value value displaye...

Page 39: ...wire connecting for Modbus function The rotating coded switch S3 0 F on the main control board of hydraulic module is used for setting the modbus address By default the units have this coded switch po...

Page 40: ...e and outdoor unit main PCB Sensor Th EA 11 Discharge pipe temperature sensor error User interface and outdoor unit main PCB Sensor Tp Ed 14 Water side heat exchanger water inlet temperature sensor er...

Page 41: ...2 L4 L5 L7 L8 or L9 occur L0 Inverter module protection Outdoor unit main PCB L1 DC bus low voltage protection Outdoor unit main PCB L2 DC bus high voltage protection Outdoor unit main PCB L4 MCE erro...

Page 42: ...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 43: ...8 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 PC...

Page 44: ...or pump can t work Yes Turn off the power check the pump step 1 revolve the pump shaft reversely around the clock by hand if can t revolve replace the pump step 2 check the wire in the pump Once that...

Page 45: ...displayed on hydronic box main PCB and user interface Possible causes Communication wires between hydronic box and user interface not connected properly Communication wiring X Y E terminals misconnec...

Page 46: ...the communication wires and high voltage wires are separated No Communication wires are close to a source of electromagnetic radiation such as transformer or strong fluorescent lamp Yes Remove the sou...

Page 47: ...cates a water side heat exchanger refrigerant inlet liquid pipe temperature sensor error Ed indicates a water side heat exchanger water inlet temperature sensor error HA indicates a water side heat ex...

Page 48: ...PCB labeled 11 in Figure 4 2 1 in Part4 2 2 Main PCB for Hydronic System Domestic hot water tank temperature sensor connection is port CN13 on the hydronic box main PCB labeled 12 in Figure 4 2 1 in P...

Page 49: ...ensor 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 runnin...

Page 50: ...t System Inverter Module Discharge pipe temperature sensor connection is port CN8 on the refrigerant system main PCBs labeled 11 in Figure 4 2 2 in Part4 2 3 Main PCBs for Refrigerant System Inverter...

Page 51: ...er interface Possible causes Hydronic box main PCB EEPROM is not connected properly Hydronic box main PCB damaged Procedure EE Hydronic box main PCB EEPROM1 is not connected properly Yes Ensure the EE...

Page 52: ...PCB and user interface Possible causes The DC generatrix voltage is too low Procedure F1 Power supply is abnormal Yes Provide normal power No LED on the Inverter Modules is lighting Yes Voltage of PN...

Page 53: ...ser interface Possible causes Outdoor unit main PCB EEPROM is not connected properly Outdoor unit main PCB damaged Procedure HF Outdoor unit EEPROM1 is not connected properly Yes Ensure the EEPROM is...

Page 54: ...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 Power supply abnormal Transformer malfunction Inter...

Page 55: ...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 and...

Page 56: ...verter driven module damaged Procedure 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 Communicatin wi...

Page 57: ...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 runn...

Page 58: ...Control Box Layout and to the M Thermal Split Engineering Data Book Part 2 5 Wiring Diagrams 2 Only applies to single phase power supply models Check the voltage between and terminals on the PFC modu...

Page 59: ...rmal Split stops running Error code is displayed on outdoor unit main PCB and user interface Possible causes Power supply voltage not within 90 110 of rated voltage Outdoor unit main PCB is damaged Pr...

Page 60: ...connection on outdoor unit main PCB is loose Yes Ensure the sensor is connected properly No High pressure sensor has short circuited or failed1 Yes Replace the sensor No Replace outdoor unit main PCB...

Page 61: ...and normal operation resumes HP indicates P0 protection has occurred 3 times in 60 minutes When an HP error occurs a manual system restart is required before the system can resume operation Error code...

Page 62: ...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 cur...

Page 63: ...ion and M Thermal Split stops running When the discharge pressure falls below 3 2MPa P1 is removed and normal operation resumes Error code is displayed on outdoor unit main PCB and user interface Poss...

Page 64: ...for Refrigerant System Inverter Module Pressure sensor connectin is port CN4 on the main control board of outdoor unit labeled 15 in Figure 4 2 2 in Part4 2 3 Main PCBs for Refrigerant System Inverte...

Page 65: ...ls 18A 8 10kW model 19A the system displays P3 protection and M Thermal Split stops running When the current returns to the normal range P3 is removed and normal operation resumes Error code is displa...

Page 66: ...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 than n...

Page 67: ...rises above 115 C the system displays P4 protection and M Thermal Split stops running When the discharge temperature falls below 90 C P4 is removed and normal operation resumes Error code is displayed...

Page 68: ...sure switch connection or pressure sensor connection on outdoor unit main PCB is loose4 Yes Ensure the pressure switch is connected properly No Pressure sensor has short circuited or failed5 Yes Repla...

Page 69: ...ponents and to Table 5 5 1 or 5 5 2 in Part 5 5 1 Temperature Sensor Resistance Characteristics 4 High pressure switch connection is port CN13 on the main PCB labeled 10 in Figure 4 2 2 in Part4 2 3 M...

Page 70: ...hanger 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 Temperature sensor not con...

Page 71: ...PCB Notes 1 Water side heat exchanger water inlet temperature sensor and water side heat exchanger water outlet temperature sensor connections are port CN6 on the hydronic box main PCB labeled11 in F...

Page 72: ...If a P6 error code is displayed on the user interface one of the following specific error codes is displayed on the outdoor unit main PCB L0 L1 L2 L4 L5 L7 L8 L9 Refer to Table 4 4 1 Table 4 4 1 Speci...

Page 73: ...dge rectifier Contactor is open the current across the PTC to charge capacitor after 5 seconds the contactor closed The capacitor output steady power supply for inverter module P N terminals In standb...

Page 74: ...module to the correct compressor terminals 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 resistance...

Page 75: ...e the compressor No Replace the inverter module3 Notes 1 Refer to Figure 4 4 1 2 Use clip on ammeter to measure the compressor current if the current is normal indicates the inverter module is failed...

Page 76: ...er module terminals U V W N P Situation 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 returne...

Page 77: ...es Replace the outdoor unit main PCB No Replace the inverter module2 Notes 1 If the fan motor is running and the DC voltage between terminals P and N on inverter module declined Relay on the main cont...

Page 78: ...heat exchanger water outlet temperature sensor water inlet temperature sensor or backup electric heater outlet water temperature sensor has short circuited or failed3 Yes Replace the temperature senso...

Page 79: ...r more than 3 seconds the system displays Pd protection and M Thermal Split stops running When the air side heat exchanger refrigerant outlet temperature returns drops below 52 C Pd is removed and nor...

Page 80: ...eplace outdoor main PCB Notes 1 Air side heat exchanger refrigerant outlet temperature sensor and outdoor ambient temperature sensor connection port are CN9 on the outdoor unit main PCB labeled 12 in...

Page 81: ...rature is higher 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 Possibl...

Page 82: ...side heat exchanger water outlet temperature sensor connections are port CN6 on the hydronic box main PCB labeled 11 in Figure 4 2 1 in Part4 2 2 Main PCB for Hydronic System 2 Measure sensor resistan...

Page 83: ...8 71 31 7 624 71 1 591 111 0 4596 8 56 37 32 7 295 72 1 537 112 0 4470 7 52 24 33 6 981 73 1 485 113 0 4348 6 49 32 34 6 684 74 1 435 114 0 4230 5 46 57 35 6 400 75 1 387 115 0 4116 4 44 00 36 6 131 7...

Page 84: ...3 38 89 73 8 643 113 2 559 6 247 8 34 37 30 74 8 358 114 2 489 5 234 9 35 35 78 75 8 084 115 2 422 4 222 8 36 34 32 76 7 820 116 2 357 3 211 4 37 32 94 77 7 566 117 2 294 2 200 7 38 31 62 78 7 321 118...

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Page 86: ...Avenue Shunde Foshan Guangdong China Postal code 528311 Tel 86 757 26338346 Fax 86 757 22390205 cac midea com global midea com Note Product specifications change from time to time as product improvem...

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