Midea M thermal Nature Series Service Manual
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Midea M thermal Nature Series Service Manual

Midea M thermal Nature Series Service Manual

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Midea Building Technologies Division
Service
Manual
M thermal Nature Series
MBT Confidential

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Summary of Contents for Midea M thermal Nature Series

  • Page 1 Midea Building Technologies Division Service Manual M thermal Nature Series MBT Confidential...
  • Page 2 M thermal Nature Series CONTENTS Part 1 General Information ................3 Part 2 Component Layout and Refrigerant Circuits ........5 Part 3 Control and Field Settings ..............18 Part 4 Diagnosis and Troubleshooting ............62 R290 Service Notice ..................166...
  • Page 3 M thermal Nature Series MBT Confidential...
  • Page 4 M thermal Nature Series Part 1 General Information 1 Product Lineup ................... 4 2 Nomenclature .................... 4 MBT Confidential...

  • Page 5: Product Lineup

    M thermal Nature Series 1 Product Lineup 220-240V/1N/50Hz 380-415V/3N/50Hz Power Supply MHC- MHC- MHC- MHC- MHC- MHC- MHC- MHC- MHC- MHC- Model V8WD2N7-B V10WD2N7-B V12WD2N7-B V14WD2N7-B V16WD2N7-B V8WD2RN7-B V10WD2RN7-B V12WD2RN7-B V14WD2RN7-B V16WD2RN7-B Appearance Note: Please note that all photos are for reference only. Actual products may vary.

  • Page 6: Refrigerant Circuits

    M thermal Nature Series Part 2 Component Layout and Refrigerant Circuits 1 Layout of Functional Components .............. 6 2 Piping Diagrams ..................10 MBT Confidential...
  • Page 7 M thermal Nature Series 1 Layout of Functional Components 1.1 8-10kW Pin Valve Electronic Expansion Valve High-pressure Sensor Main Control Box Inverter Control Box Low-pressure Sensor Water Pump Water-Flow Switch Plate Heat Exchanger High-pressure Switch Compressor MBT Confidential...
  • Page 8 M thermal Nature Series Liquid Reservoir Safty Valve Air-purge Valve 4-way Valve MBT Confidential...
  • Page 9 M thermal Nature Series 1.2 12-16kW High-pressure Sensor Main Control Box Inverter Control Box Low-pressure Sensor Flow Switch High-pressure Switch Water Pump Plate Heat Exchanger Compressor MBT Confidential...
  • Page 10 M thermal Nature Series Electronic Expansion Valve Liquid Reservoir Safty Valve Air-purge Valve 4-way Valve MBT Confidential...

  • Page 11: Piping Diagrams

    M thermal Nature Series 2 Piping Diagrams Refrigerant piping graphic example: High-temperature, high-pressure gas Medium-temperature, high-pressure liquid Low-temperature, low-pressure gas liquid mixture Low-temperature, low-pressure gas Note: Direction of refrigerant flow depicted in diagram represents main refrigerant flow and is for illustration purposes only.

  • Page 12: Cooling Mode

    M thermal Nature Series 2.2 Cooling mode 2.3 Key components Compressor Tp Discharge temperature sensor Th Return-air temperature sensor High-pressure switch H-SEN High-pressure sensor 4-way valve L-SEN Low-pressure sensor T4 Ambient temperature sensor error Finned tube Heat exchanger T3 Outdoor unit heat exchanger bottom temperature sensor...
  • Page 13 M thermal Nature Series Plate heat exchanger Tw_out Plate heat exchanger outlet water temperature sensor Automatic air purge valve Water pressure sensor (optional) Pressure relief valve Water pump Backup heater(optional) T1 Backup heater outlet water temperature sensor (equipped with backup heater) ...

  • Page 14: Table Of Contents

    M thermal Nature Series Part 3 Control and Field settings 1 Shut-off Operation ................... 20 2 Standby Control ..................20 3 Startup Control ..................21 4 Normal Operation Control ............... 24 5 System protection features ..............26 6 Special Control ..................31 7 User Interface Field Settings..............
  • Page 15 M thermal Nature Series Notice  Refer to system diagram below for location of key components and sensors.  The diagram below is for reference only. Actual installations will vary based on unique system configurations. MBT Confidential...

  • Page 16: Shut-Off Operation

    M thermal Nature Series 1 Shut-off Operation The unit will automatically shut off if one of the following occurs:  System abnormality: to protect the compressor, a thermal sensor will automatically shut the system off if it detects any abnormality that could potentially cause damage. An error code will show on both the outdoor unit PCB digital display and the user interface.

  • Page 17: Startup Control

    M thermal Nature Series 3 Startup Control 3.1 Compressor Startup Delay Control Startup control and restart control delay compressor startup by three minutes from the last stoppage in order to prevent the potentially harmful effects of frequent compressor on/off cycling and also ensures that pressure within the refrigerant system remains equalized.
  • Page 18 M thermal Nature Series 12-16kw compressor startup program when cooling mode ambient temperature is above 12°C and when heating mode ambient temperature is above 0°C 12-16kw compressor startup program when cooling mode ambient temperature is below 12°C and when heating mode ambient temperature is below 0°C...
  • Page 19 M thermal Nature Series 3.3 Startup Control for Heating and Domestic Hot Water (DHW) Operation Component control during startup in heating and domestic hot water modes Component Wiring diagram label 8-16kW Control functions and status Compressor startup program selected according to...

  • Page 20: Normal Operation Control

    M thermal Nature Series 4 Normal Operation Control 4.1 Component Control during Normal Operation Component control during heating and domestic hot water (DHW) operations Component Wiring diagram label Control functions and status 8-16kW Controlled according to load requirement determined by...

  • Page 21: Electronic Expansion Valve Control

    M thermal Nature Series 4.5 Electronic Expansion Valve Control The electronic expansion valve (EXV) is controlled in increments from 0 (fully closed) to 480 (fully open).  At power-on:  The EXV first closes fully, then moves to the standby at the 480 increments position. After the compressor activates, the EXV control is determined by suction superheat discharge temperature, pressure, discharge temperature and compressor speed.

  • Page 22: System Protection Features

    M thermal Nature Series 5 System protection features 5.1 High Pressure Protection This feature protects the refrigerant system from abnormally high pressure and also protects the compressor from transient spikes in pressure. High pressure protection control Normal operation > 3.5MPa <...
  • Page 23 M thermal Nature Series 5.3 Discharge Temperature Protection Control This control protects the compressor from abnormally high temperatures and transient spikes in temperature. High discharge temperature protection control Normal operation Discharge temperature > 115°C Discharge temperature < 95°C High discharge temperature protection, error code P4 is displayed When the discharge temperature rises above 115°C the system displays the error code P4 and the unit shuts down.
  • Page 24 M thermal Nature Series 5.5 Voltage Protection Control This control protects the M-Thermal Split from abnormally high or abnormally low voltages. Figure 3-5.6: Compressor voltage protection control Normal operation Voltage ≥ 265V 180V≤Voltage < 256V for 30s or Voltage ≤ 172V...
  • Page 25 M thermal Nature Series Anti-freezing control in Cooling mode Cooling mode Min(Twout,Twin,T1)<4 and lasts 5s Compressor stops, water pump keeps running at the maximum output for 5 mins Min(Twout,Twin,T1) 8 Anti-freezing protection in cooling mode Turn to Off Status and running anti-freezing...
  • Page 26 M thermal Nature Series Anti-freezing control in Off status/ Heating mode/ DHW mode Off Status / Heating mode / DHW mode Turn to Off Status 1.T4<3 ，and Min(Twout,Twin,T1)<4 lasts 5s 2.Min(Twout,Twin,T1)<2 Compressor stops, water pump keeps running at the maximum output for 5 mins Min(Twout,Twin,T1)<8...

  • Page 27: Special Control

    M thermal Nature Series 6 Special Control 6.1 Oil Return Operation In order to prevent the compressor from running out of oil, the oil return operation is conducted to recover oil that has flowed out of the compressor and into the refrigerant piping. When the oil return operation is being conducted, the outdoor unit refrigerant system main PCB displays code d0.

  • Page 28: User Interface Field Settings

    M thermal Nature Series 7 User Interface Field Settings 7.1 Introduction During installation, the parameters setting should be configured by the installer to suit the installation configuration, climate conditions and end-user preferences. The relevant settings are accessible and programmable through the FOR SERVICEMAN menu on the user interface.

  • Page 29: Menu Structure

    M thermal Nature Series 7.2 Menu Structure MBT Confidential...
  • Page 30 M thermal Nature Series 7.3 FOR SERVICEMAN Menu For serviceman allows installers to input the system configuration and set the system parameters. Press simultaneously for 3 seconds to enter the authorization page. Press to navigate cursor and press to adjust the numerical values. The password is 234. Press to enter For serviceman menu.

  • Page 31: Setting Description

    M thermal Nature Series 7.3.1 DHW heating setting 7.3.1.1 DHW mode DHW mode defines whether hot water demand is needed. Setting Description Enable DHW mode if DHW tank is installed. Disable DHW mode if DHW tank is not installed. In this case, no need to define other settings in DHW setting, all other settings in DHW setting will be invisible.
  • Page 32 M thermal Nature Series 7.3.1.3 DHW priority, DHW priority time set, t_DHWHP_RESTRICT, t_DHWHP_MAX DHW priority defines whether domestic hot water or space heating/cooling takes priority. Setting Description When DHW demand and space heating/cooling demand both exist, heat pump will heat the water according to...
  • Page 33 M thermal Nature Series Heating/Cooling turns to DHW turns to PRIORITY PRIORITY t_DHWHP_RESTRICT t_DHWHP_MAX Heating/Cooling TIME SET andand DHW mode ON || DHW mode OFF andand T5<MIN(T5S, T5STOP)- T5≥MIN(T5S, dT5_ON T5STOP) andand Heating/Cooling mode mode A min B min operates for A mins...
  • Page 34 M thermal Nature Series Setting Description Enable DHW pump run in timer. Disable DHW pump run in timer. PUMP_D RUNNING TIME defines the period that DHW pump operates for each timer Diagram below illustrates the effects of PUMP_D RUNNING TIME when Pump_D is installed and PUMP_D TIMER is enable.
  • Page 35 M thermal Nature Series 7.3.1.7 T4DHWMAX, T4DHWMIN T4DHWMAX defines the ambient temperature above which heat pump and AHS/IBH may have different actions. When T4DHWMAX≤T4 and T4DHWMAX<43, both compressor and AHS/IBH stop running. When T4HMAX≤T4 and T4DHWMAX=43, compressor runs with lowest frequency and AHS/IBH runs according to user demand.
  • Page 36 M thermal Nature Series Heat pump ON with lowest Heat pump ON compressor frequency T4CMIN T4CMAX Abrreviations: T4: Outdoor ambient temperature 7.3.2.4 dT1SC dT1SC defines water temperature hysteresis of activating heat pump. When T1 – T1S ≥ dT1SC and heat pump is within operating ambient temperature range, heat pump provides chilled water to space cooling terminals.
  • Page 37 M thermal Nature Series 7.3.3 Heating setting 7.3.3.1 Heating mode Heating mode defines whether space heating demand is needed. Setting Description Enable heating mode if space heating terminals are installed. Disable heating mode if space heating terminals are not installed. In this case, no need to define other settings in Heating mode, all other settings in Heating mode will be invisible.
  • Page 38 M thermal Nature Series 7.3.3.5 dTSH dTSH defines room temperature hysteresis of stopping heat pump. dTSH is only applicable if YES is selected for Room temp. in the Temp. type setting. When TS – Ta ≥ dTSH and heat pump is within operating ambient temperature range, heat pump provides hot water to the...
  • Page 39 M thermal Nature Series 7.3.4.1 T4AUTOCMIN, T4AUTOHMAX T4AUTOCMIN defines the ambient temperature below which the heat pump will not provide chilled water for space cooling in auto mode. T4AUTOHMAX defines the ambient temperature above which the heat pump will not provide hot water for space heating in auto mode.
  • Page 40 M thermal Nature Series 7.3.5.3 Double zone Double zone defines the number of zones. Setting Description Double zones control Single zone control Figure below illustrates the effects of different combinations in Temp. type setting. For single zone control WATER FLOW TEMP.
  • Page 41 M thermal Nature Series If Room thermostat setting is defined as MODE SET, the interface appears: Mode set priority defines whether cooling mode or heating mode takes priority. Setting Description Heating When heating and cooling switch signal are closed simultaneously, heat pump runs in heating mode.
  • Page 42 M thermal Nature Series T4: Outdoor ambient temperature IBH: Electric heater T4HMIN: The ambient temperature below which the heat pump will not operate in heating mode. T4HMAX: The ambient temperature above which the heat pump will operate heating mode with lowest compressor frequency.
  • Page 43 M thermal Nature Series with heat pump depends on the water temperature and heat pump status. Enable EnSWITCHPDC function, T4_AHS_ON is calculated according to price of gas and electricity and the efficiency of boiler and heat pump. Only Additional heating source works at ambient temperature of T4_AHS_ON because of the economic performance and system high efficiency.
  • Page 44 M thermal Nature Series Note: Only when t_TBH_DELAY, T4_TBH_ON are met at the same time then tank booster heater turns on. P_TBH defines the power input of tank booster heater, which is used for energy consumption statistics. Diagram below illustrates the operation of heat pump and tank booster heater of DHW mode.
  • Page 45 M thermal Nature Series Restore factory settings is used to restore all the parameters (including energy metering data and WLAN setting) set in the user interface to factory defaults. On selecting YES, the process of restoring all settings to factory defaults begins and progress is displayed as a percentage.
  • Page 46 M thermal Nature Series 7.3.10.2 Air purge Once installation is complete, it is important to run the air purge function to remove any air which may be present in the water piping and which could cause malfunctions during operation. Before running Air purge mode, make sure that the air purge valve is open.
  • Page 47 M thermal Nature Series 7.3.10.4 Cooling running The Cooing running operation is used to check the operation of the system in space cooling mode. During the Cooing running operation, the leaving water set temperature is 7°C. The current actual leaving water temperature is displayed on the user interface.
  • Page 48 M thermal Nature Series 7.3.11.1 Preheating for floor Preheating for floor function provides mild heat to the underfloor water piping for the first time during seasonal heating, diminish the risk of damage to the floor and piping system. Setting Description...
  • Page 49 M thermal Nature Series subfloor to prevent warping or rupture of the floor. Heat pump provides mild heat to the concrete or other structural material around the underfloor water piping in a certain period of time, accelerate the process of getting rid of moisture. During floor drying up operation, the temperature of the floor would be increased gradually.
  • Page 50 M thermal Nature Series Disable auto restart cooling/heating mode Enable auto restart cooling/heating mode Auto restart DHW mode Setting Description Disable auto restart DHW mode Enable auto restart DHW mode 7.3.13 Power input limitation Power input limitation makes the machine suitable for a variety of current supplies. There are 8 configurations for user to choose according to the maximum allowable access current .
  • Page 51 M thermal Nature Series TBH ON/OFF Remote ON/OFF control of tank booster heater AHS ON/OFF Remote ON/OFF control of auxiliary heating source Smart grid defines whether SMART GRID control signal is connected to hydronic PCB. Setting Description Disable Smart grid function...
  • Page 52 M thermal Nature Series Stop bit 1 Stop bit 2 7.3.17 Common setting 7.3.17.1 t_DELAY PUMP t_DELAY PUMP defines the delayed stop time of Pump_I. Pump_I will stop t_DELAY PUMP minutes later after compressor stops base on system temperature equalization consideration.
  • Page 53 M thermal Nature Series 7.3.18 Clear energy data Once selecting YES, All energy metering data is clear. 7.3.19 Intelligent function settings 7.3.19.1 Energy correction The actual installation scenario would be different from one to another. The energy metering calculation of the unit could deviate slightly due to the actual installation.

  • Page 54: Operation Parameter

    M thermal Nature Series If Sensor backup setting function is stopped, the bubble will hide automatically. If the timer runs out, the bubble hides and unit will shut down due to the existed error. In cascade installation, Sensor backup setting function is available for master unit only.
  • Page 55 M thermal Nature Series MBT Confidential...

  • Page 56: Usb Function Field Settings

    M thermal Nature Series 8 USB Function Field Settings USB function helps you to transmit parameters and program easily. When USB disk connect to CN4 port of main control PCB, the USB function interface appears automatically on the wired controller.
  • Page 57 M thermal Nature Series Sub-function 3: Please make sure there is only one applicable hydraulic system program in the USB disk before using this function. Sub-function 4: Please make sure there is only one applicable refrigerant system program in the USB disk before using this function.

  • Page 58: Troubleshooting

    M thermal Nature Series Part 4 Diagnosis and Troubleshooting 1 Service Information .................. 63 2 Electric wiring diagram ................71 3 Electric Control Box Layout ............... 76 4 Outdoor Unit PCBs ................... 79 5 Error Code Table ..................88 6 Troubleshooting ..................91 7 Discharge / Suction pressure and temperature range ......

  • Page 59: Service Information

    M thermal Nature Series 1 Service Information DANGER！  These instructions are exclusively intended for qualified contractors and authorized installers  Work on the refrigerant circuit with flammable refrigerant in safety group A3 may only be carried out by authorized heating contractors.
  • Page 60 M thermal Nature Series substance that may corrode refrigerant-containing components, unless the components are constructed of materials that are inherently resistant to corrosion or are suitably protected from corrosion 1.4 Check of Electrical Devices Repair and maintenance of electrical components should include initial safety checks and component inspection procedures.
  • Page 61 M thermal Nature Series Packaging  Dispose of the packaging properly.  Observe all relevant regulations Refrigerant Removal, Evacuation, Charge, Recovery, and Unit Decommissioning WARNING！ Due to the feature of the R290 refrigerant, only carry out work when you have specific expert refrigeration knowledge and are competent for handling R290 refrigerant.
  • Page 62 M thermal Nature Series work properly. Hoses should be complete with leak-free disconnection couplings and in good conditions. Before using the recovery equipment, check and verify that it works properly and has been properly maintained, and that any associated electrical components are sealed to prevent ignition in the event of a refrigerant leakage. Consult the manufacturer in case of any doubt.
  • Page 63 M thermal Nature Series 1.9 R290 System Service When repairing systems that use R290 refrigerant, the following warnings and operating requirements should be noted. Warning about the R290 refrigerant The following information indicates a hazard with a medium level of risk which, if not avoided, could result in death or serious injury.
  • Page 64 M thermal Nature Series – if an indirect refrigerating circuit is being used, the secondary circuit shall be checked for the presence of refrigerant; – marking to the equipment continues to be visible and legible. Markings and signs that are illegible shall be corrected;...
  • Page 65 M thermal Nature Series render the unit safe. This process may need to be repeated several times. Compressed air or oxygen shall not be used for this task. Flushing shall be achieved by breaking the vacuum in the system with OFN and continuing to fill until the working pressure is achieved, then venting to atmosphere, and finally pulling down to a vacuum.
  • Page 66 M thermal Nature Series Before using the recovery machine, check that it is in satisfactory working order, has been properly maintained and that any associated electrical components are sealed to prevent ignition in the event of a refrigerant release. Consult manufacturer if in doubt.

  • Page 67: Electric Wiring Diagram

    M thermal Nature Series 2 Electric wiring diagram 1Ph 8-16kW MBT Confidential...
  • Page 68 M thermal Nature Series MBT Confidential...
  • Page 69 M thermal Nature Series 3Ph 8-16kW MBT Confidential...
  • Page 70 M thermal Nature Series MBT Confidential...
  • Page 71 M thermal Nature Series BMS application MBT Confidential...

  • Page 72: Electric Control Box Layout

    M thermal Nature Series 3 Electric Control Box Layout 1Ph 8-10kW Inverter Control Box (Inverter PCB’s inside) Main Control PCB Power terminal blocks Main Control Box 3Ph 8-10kW Inverter Control Box (Inverter PCB’s inside) Main Control PCB Power terminal blocks...
  • Page 73 M thermal Nature Series 1Ph 12-16kW Inverter Control Box (Inverter PCB’s inside) Main Control PCB Power terminal blocks Main Control Box 3Ph 12-16kW Inverter Control Box (Inverter PCB’s inside) Main Control PCB Power terminal blocks Main Control Box MBT Confidential...
  • Page 74 M thermal Nature Series Note: For maintenance, the unit has retrofitted its structure for better after-service experience. Without removing the top cover, the aftersales personnel can maintain and troubleshoot the unit by just removing the right side panel. Main Control PCB consists of Refrigerant system and hydronic system, which is sealed in the hermetic electric control box and placed vertically for safety consideration.

  • Page 75: Outdoor Unit Pcbs

    M thermal Nature Series 4 Outdoor Unit PCBs 4.1 Main Control PCB MBT Confidential...
  • Page 76 M thermal Nature Series Label Port Code Content Rated Voltage CN21 POWER Port for power supply 230VAC S1, S2, S3, Dip switch S5, S6, SW9 CN33 EEV1 Port for electrical expansion valve1 0-12V DC H-SEN Port for high-pressure sensor 0-5V DC...
  • Page 77 M thermal Nature Series Label Port Code Content Rated Voltage (Port1, 2) - Additional heat source ( Port3, 4) - Port for SV1(3-way valve) ( Port5, 6) - Port for SV2(3-way valve) ( Port7, 8) - Port for SV3(3-way valve)
  • Page 78 M thermal Nature Series DIP switch settings DIP switch: ON=1 OFF=0 Description Default factory setting Reserved 0= Integrated electric heater 1= External electric heater 0/0= Without backup heater 0/1= With backup heater(One step control) 3: OFF 1/0= With backup heater(Two step...

  • Page 79: Inverter Pcb

    M thermal Nature Series 4.2 Inverter PCB Single Phase 8-10kW Inverter PCB Voltage Port Code Content Label CN32 DC fan power ports Above 30V AC (varying according to frequency) CN12 Port for communication with Main control board 0-12V DC CN25...
  • Page 80 M thermal Nature Series Single Phase 12-16kW Inverter PCB Voltage Port Code Content Label Power output U of inverter module to compressor Above 90V AC (varying according to frequency) Power output V of inverter module to compressor Above 90V AC (varying according to frequency)
  • Page 81 M thermal Nature Series Three Phase 8-16kW Inverter PCB Voltage Label Port Code Content Power input L1 of inverter PCB Phase to phase voltage 380VAC Power input L2 of inverter PCB Phase to phase voltage 380VAC Power input L3 of inverter PCB...
  • Page 82 M thermal Nature Series 4.3 IBH PCB 1Ph 3kW IBH PCB Voltage Label Port Code Content CN22 Power input L of IBH PCB Phase to phase voltage 230VAC 3KW-2 Power input N of 3KW IBH Phase to phase voltage 230VAC...
  • Page 83 M thermal Nature Series 3Ph 9kW IBH PCB Voltage Label Port Code Content CN22 L1 L2 L3 Power input L1/L2/L3 of IBH PCB Phase to phase voltage 380VAC 3KW-3 Power input L3 of 3KW IBH Phase to phase voltage 380VAC...

  • Page 84: Error Code Table

    M thermal Nature Series 5 Error Code Table Water circuit error Error code Description Displayed on water flow failure (10 times of E8) User Interface and Main Control PCB water flow protection User Interface and Main Control PCB Communication error...
  • Page 85 M thermal Nature Series Voltage error Error code Description Displayed on Phase loss or phase reversal User Interface and Main Control PCB For 3Ph units Power overvoltage and Power under-voltage protection User Interface and Main Control PCB Protection code Error code...
  • Page 86 M thermal Nature Series Instantaneous overcurrent of PFC software protection Main Control PCB For 3Ph units PFC low voltage protection Main Control PCB For 3Ph units Over-temperature protection of PFC module Main Control PCB For 3Ph units PFC module CBC overcurrent error protection...

  • Page 87: Troubleshooting

    M thermal Nature Series 6 Troubleshooting 6.1 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 88 M thermal Nature Series 6.2 E0, E8 Troubleshooting Digital display output Description Error code Description water flow failure water flow protection 5 times of No-water detection failures in a row before pump on No-water detection failures before pump Triggering on or water flow switch breaks after...
  • Page 89 M thermal Nature Series Layout of main component E0(**%) /E8(**%) is displayed on the User Interface. The percentage indicates possible cause of water flow failure, which is illustrated as note 1. User Interface Correct Dip switch Procedure E0 / E8: Water flow failure...
  • Page 90 M thermal Nature Series Check the water pump indicator lights, and it shows water pump is normal (Willo water pump green light indicates Check the details of Note 2 normal ; Xinjie water pump 5 lights all on indicates normal) Check the water circuit, and it is abnormal: 1.
  • Page 91 M thermal Nature Series Note 1 : The meaning of percentage of water pump output(displayed on the user interface) Percentage Water pump model Brand Description Para 25/9 IPWM-130-1 WILO IPWM connection port short circuited APM25-9-130/180 SHIMGE PWM feedback signal loss...
  • Page 92 M thermal Nature Series Note 3: The possible error and solutions of water pump water pump failure The possible causes of and solutions Description Possible cause Solution Water pump leak Replace the sealing ring Water inlet and outlet pipe connected Connect the pipe securely.
  • Page 93 M thermal Nature Series 6.3 E2 Troubleshooting Digital display output Description Error code Description Communication fault between User Interface and Main Control PCB Main Control PCB side: Communication failure with User Interface lasts 2 mins Triggering User Interface side: No communication reply from Main Control PCB for 1 min...
  • Page 94 M thermal Nature Series Procedure E2: Communication fault between User Interface and the unit Communication cables from port X/HA, Reconnect the communication cables Y/HB was disconnected, or misconnected securely Communication cables from port X/HA, Replace the communication cables Y/HB have short circuited or damaged...
  • Page 95 M thermal Nature Series 6.4 H0 Troubleshooting Digital display output Description Error code Description Communication error of Main Control PCB Triggering Communication failure lasts 1 min Procedure H0: Communication error of Main Control PCB Replace the Main Control PCB MBT Confidential...
  • Page 96 M thermal Nature Series 6.5 H1 Troubleshooting Digital display output Description Error code Description Communication error between Main Control PCB and inverter PCB Triggering Communication failure occurs after powering on the unit for 2 mins CN43 COMM (Main Control PCB) LED2 &...
  • Page 97 M thermal Nature Series For 1Ph models H1：Communication error between Main Control PCB and Inverter PCB Check whether power supply for ODU is abnormal.( The normal Adjust power supply range is around 190-264V Check whether the LED2 on If yes, replace...
  • Page 98 M thermal Nature Series For 3Ph units H1：Communication error between Main Control PCB and Inverter PCB 1. Check whether power supply for ODU is abnormal.( The normal 1.Adjust power supply range is around 342-456V) 2.Connect L1, L2, L3 securely and 2.
  • Page 99 M thermal Nature Series 6.6 Hd Troubleshooting Digital display output Description Error code Description Communication fault between master unit and slave unit. For cascade system, the communication failure between master Triggering unit and slave unit lasts 2mins and above Communication port...
  • Page 100 M thermal Nature Series Procedure Hd：The communication fault between master unit and slave unit. Check “Unit Status-Operation parameter- Online unit number” on the User Interface, and the number is consistent with the actual unit number Communication cables between port Reconnect the communication cables...
  • Page 101 M thermal Nature Series 6.7 E5, E6, E9, EA, FC1, H2, H3 Troubleshooting Digital display output Description Code Description Port Locations T3 Outdoor unit heat exchanger CN34 bottom temperature sensor error T4 Ambient temperature sensor error CN45 Th Return-air temperature sensor...
  • Page 102 M thermal Nature Series Procedure E5, E6, E9, EA, FC1, H2, H3： Temperature sensor error Loose, misconnected, broken or wet Reconnect the temperature sensor temperature sensor connection on Main securely and ensure it remains dry Control PCB. Pull out temperature sensor, measure sensor resistance: If the resistance is too low(<...
  • Page 103 M thermal Nature Series 6.8 E3, E4, E7, Eb, EC, Ed, HA, H9 Troubleshooting Digital display output Description Code Description Port Locations (Main Control PCB) T1 Electric Heater/AHS water outlet CN39 temperature sensor error T5 Water tank temperature sensor CN13...
  • Page 104 M thermal Nature Series Switch IBH Dip switch Note 1: Dip switch settings or User Interface settings Code Description Main Control PCB can not detect the right sensor value. IBH function is on(Dip switch S1-3/4 is set IBH available, and User Interface- For Serviceman - Other heat source –...
  • Page 105 M thermal Nature Series Procedure E3, E4, E7, Eb, EC, H9: Temperature sensor error Check the Dip switch settings or User Reset dip switch, and reboot the unit, Interface settings as illustrated above, Ensure parameter are set available and it keeps the same...
  • Page 106 M thermal Nature Series 6.9 H5 Troubleshooting Digital display output Description Code Description Locations Ta room temperature sensor error Inserted on User Interface PCB Procedure H5：Ta Temperature sensor error Replace User Interface MBT Confidential...
  • Page 107 M thermal Nature Series 6.10 H8, P21, P27 Troubleshooting Digital display output Description Code Description Port Locations(Main Control PCB) H-SEN High-pressure sensor error L-SEN Low-pressure sensor error CN46 H-SEN and L-SEN connected in reverse CN3/ (detect when compressor is off)
  • Page 108 M thermal Nature Series Procedure H8, P21: Pressure sensor error Loose, misconnected, broken or wet Reconnect the temperature sensor temperature sensor connection on Main securely and ensure it remains dry Control PCB. Measure the resistance value of sensor, and it’s consistent with the curve(Refer...
  • Page 109 M thermal Nature Series 6.11 E1 Troubleshooting Digital display output Description Error code E1 (For 3Ph units) Description Phase loss or phase reversal Triggering At least one of L1/L2/L3/N is misconnected or disconnected Relative Terminal ports and blocks Locations Procedure...
  • Page 110 M thermal Nature Series 6.12 H7 Troubleshooting Digital display output Description Error code Description Power overvoltage and power undervoltage protection Input voltage<170V or Input voltage≥265V Triggering (The unit operating normally if 250V≥input voltage≥180V) Procedure H7: Power overvoltage and power undervoltage protection...
  • Page 111 M thermal Nature Series 6.13 P0 Troubleshooting Digital display output Description Error code Description Low-pressure protection 1. Main Control PCB detected that the low pressure <0.12MPa lasting more than 30 mins 2. Main Control PCB detected that low pressure <0.13MPa & compressor shutting off Triggering more than 2 mins at the same time.
  • Page 112 M thermal Nature Series Procedure P0: Low-pressure protection Check “Unit Status-Operation parameter- P1 comp. pressure & P2 comp. pressure” Replace low-pressure sensor on the User Interface and P1=P2 while the unit is off T4 sensor fell out from the fixed position...
  • Page 113 M thermal Nature Series Reboot the unit, hold the electronic Check for blockages between the expansion valve coil to feel whether it is electronic expansion valve and Copper working, and listen for a “Click” sound filter. Clean the unit again, and recharge...
  • Page 114 M thermal Nature Series 6.14 P1 Troubleshooting Digital display output Description Error code Description High-pressure switch protection Main Control PCB detected high-pressure ≥ 3.5 Mpa Triggering High-pressure switch The Locations of high-pressure switch refer to Part 2, Component Layout and...
  • Page 115 M thermal Nature Series Procedure P1 occurs in Cooling mode High-pressure switch plug from the inverter control box is loose or Reconnect high-pressure switch securely misconnected Use a digital multimeter to measure high- pressure switch with buzzer. Power off and power on again , P1 error If buzzer doesn’t sound, replace high-...
  • Page 116 M thermal Nature Series Request aftersales service P1 occurs in Heating/DHW mode Check and clean pipe and filter, Ensure Check “Unit Status-Error info.” on water pressure and water-flow rate is in the User Interface, and E8/E0/P5 code Proper range as above.
  • Page 117 M thermal Nature Series The proper water pressure range:(0.3bar-3bar) The proper water flow rate range P1 occurs in Off status Check “Unit Status-Operation parameter- P1 comp. pressure & P2 comp. pressure” Request aftersales service on the User Interface, and P1&P2<3.5MPa...
  • Page 118 M thermal Nature Series 6.15 P3 Troubleshooting Digital display output Description Error code Description Overcurrent protection Triggering Main Control PCB detected that the input current is higher than protection value Terminal block Procedure P3 occurs in heating/DHW mode Measure the input voltage of terminal block, Adjust the power supply based on the and it’s<198V...
  • Page 119 M thermal Nature Series Reboot the unit, hold the electronic expansion valve coil to feel whether it is Request aftersales service working, and listen the “Click” sound when the valve turn on/off. Power off the unit, confirm whether Reconnect the compressor cables...
  • Page 120 M thermal Nature Series P3 occurs in cooling mode Measure the input voltage of terminal block, Adjust the power supply based on the and it’s<198V rated voltage range Use a current clamp to measure the current between two power cables connected to “L”...
  • Page 121 M thermal Nature Series misconnected Use a digital multimeter to measure the resistance between each two of compressor terminals. If the resistance <10 Ohm or the Replace the compressor resistance=0 (Short circuited), compressor failed Power off the unit, and identify possible inverter PCB failure.
  • Page 122 M thermal Nature Series 6.16 P4 Troubleshooting Digital display output Description Error code Description Compressor protection against excessively-high discharge temperature Main Control PCB detected that the compressor discharge temperature was ≥115℃ Triggering Tp discharge temp. sensor Relative ports and Locations...
  • Page 123 M thermal Nature Series Procedure Pull out Tp temperature sensor from compressure fixed sleeve, leave it in the air for 10 mins, if the temperature difference between sensor and air is greater than 5℃, the sensor failed. Replace Tp temperature sensor You can also measure the resistance and compare it with sensor’s resistance...
  • Page 124 M thermal Nature Series 6.17 Pd Troubleshooting Digital display output Description Error code Description Protection for excessively-high condensing temperature in cooling mode Main Control PCB detected that the condensing temperature was ≥65℃ in cooling Triggering mode Relative ports and Locations...
  • Page 125 M thermal Nature Series Procedure Pd: Protection for excessively-high condensing temperature in cooling mode Check “Unit Status-Operation parameter- Replace Main Control PCB or high- P1 comp. pressure & P2 comp. pressure” pressure sensor.（Refer to H8/P21 on the User Interface and P1=P2 while...
  • Page 126 M thermal Nature Series 6.18 HP Troubleshooting Digital display output Description Error code Description Low-pressure protection in cooling mode Main Control PCB detected that the suction pressure P2<0.35Mpa for 5 seconds in Triggering cooling mode and compressor running over 300 seconds.
  • Page 127 M thermal Nature Series Procedure HP: Low-pressure protection in cooling mode Install the Tw_out sensor back to the Check whether Tw_out sensor felt out installation port so actual temperature from installation port can be detected. Pull out Tw_out/Tw_in sensor from plate...
  • Page 128 M thermal Nature Series 6.19 bA Troubleshooting Digital display output Description Error code Description T4 sensor out of operation range protection In heating/ DHW mode, the error occurs when T4≥65℃ or T4<-25℃ Triggering In cooling mode, the error occurs when T4≥65℃ or T4<-5℃...
  • Page 129 M thermal Nature Series Procedure bA: T4 sensor out of operation range protection The actual ambient temperature ≥65℃ The actual ambient temperature is out of or <-25℃ in heating mode; or the actual range, so Protection program activated. ambient temperature≥65℃ or <-5℃...
  • Page 130 M thermal Nature Series 6.20 PP, Hb Troubleshooting Digital display output Description Error code Protection for abnormal temperature Description difference between outlet water and inlet PP occurs 3 times in heating/DHW mode water Twout-Twin≥3℃ and lasts 15 mins in PP occurs 3 times in heating/DHW mode;...
  • Page 131 M thermal Nature Series Procedure PP in cooling mode Outlet pipe and inlet pipe connected Re-connect the pipes securely reversely Tw_in sensor and Tw_out sensor connected reversely on plate heat Re-connect the sensors securely exchanger or on Main control PCB...
  • Page 132 M thermal Nature Series PP/Hb in heating/DHW mode Outlet pipe and inlet pipe connected Re-connect the pipes securely reversely Tw_in sensor and Tw_out sensor connected reversely on plate heat Re-connect the sensors securely exchanger or on Main control PCB Pull out Tw_out/Tw_in sensor from plate...
  • Page 133 M thermal Nature Series 6.21 P5 Troubleshooting Digital display output Description Error code Description The big temperature difference between outlet water temp. and inlet water temp. Twout-Twin≥30℃ in heating/DHW mode Triggering Twout-Twin≥17℃ in cooling mode Tw_in Tw_out Procedure P5：The big temperature difference between outlet water temp.
  • Page 134 M thermal Nature Series compare with sensor’s resistance characteristics table (Refer to part 4 Appendix), If the resistance is not consistent, the sensor has failed. Whether the heating water temperature rises rapidly, the cooling water temperature drops rapidly and the unit stops quickly.
  • Page 135 M thermal Nature Series 6.22 F75 Troubleshooting Digital display output Description Error code Description Protection for insufficient discharge overheating degree. Triggering Tp-Tc < 0℃ and last 10 mins Tp discharge temp. sensor Nameplate Refer to Nameplate for rated refrigerant charge volume.
  • Page 136 M thermal Nature Series Pull out Tp temperature sensor from compressor fixed sleeve, leave it in the Replace discharge temperature sensor and it air for 10 mins, if the temperature will be back to normal automatically difference between sensor and air is greater than 5℃, the sensor failed...
  • Page 137 M thermal Nature Series 6.23 F1 Troubleshooting Digital display output Description Error code Description Protection for DC bus undervoltage Triggering For single phase inverter PCB, the DC bus voltage≤200VDC BUS voltage(P-N) (Inverter PCB) MBT Confidential...
  • Page 138 M thermal Nature Series Procedure For single phase: F1: Protection for DC bus undervoltage Power off the unit, and identify possible inverter PCB failure. (Refer to part 4 Replace the inverter control box Appendix: Guide for identifying inverter PCB failure) Power on the unit, when it’s standby,...
  • Page 139 M thermal Nature Series 6.24 C7 Troubleshooting Description Error code Description Excessively-high temperature protection for IPM module IPM module temperature ≥ 95℃ Triggering Digital display output Procedure C7：Excessively-high temperature protection for IPM module The unit was installed on a site with...
  • Page 140 M thermal Nature Series 6.25 H4, L** Troubleshooting Digital display output Description Error code Description Note 3 times of “L1*” in 60 mins Check the specific code on digital display panel on the Inverter module protection Main Control PCB The specific L** code table:...
  • Page 141 M thermal Nature Series Module type mismatch Motor failed to start Motor stalling protection Phase loss protection Compressor terminals short circuit protection IPM short circuit protection Action of high-pressure switch PED bH error PFC HARDWARE OVERCURRENT PROTECTION For 3Ph units...
  • Page 142 M thermal Nature Series Procedure H4, L**: Inverter module protection Power off the unit, the compressor connection cables was disconnected, or Reconnect the cables securely misconnected Use a digital multimeter to measure the resistance between each two of compressor terminals. If the resistance Replace the compressor <10 Ohm or the resistance=0 (Short...
  • Page 143 M thermal Nature Series 6.26 H6, HH, J** Troubleshooting Digital display output Description Error code Description Note Fan failure 10 times of H6 in 120mins Check the specific code on digital display panel on the Fan module failure Main Control PCB...
  • Page 144 M thermal Nature Series Procedure H6, HH: Fan failure Power off the unit, the fan connection cables was disconnected, or Reconnect the cables securely misconnected Use a digital multimeter to measure the resistance between each two of fan Replace the fan terminals.
  • Page 145 M thermal Nature Series 6.27 HF Troubleshooting Digital display output Description Error code Description Outdoor unit EEPROM error The driving program of inverter PCB is detected as being mismatched with Dip Triggering switch Relative ports Dip switch S5 S6 and Locations series N:1/0/0/0 0/0/1/1-8kW、0/1/0/0-10kW、0/1/0/1-12kW、0/1/1/0-14kW、0/1/1/1-...
  • Page 146 M thermal Nature Series 6.28 Pb Troubleshooting Digital display output Description Error code Description Pb is the indicator that shows the system is running in anti-freezing control Triggering Refer to Part 3 - Protection control – Anti-freezing protection control User Interface...
  • Page 147 M thermal Nature Series 6.29 C2 Troubleshooting Digital display output Description Error code Description Relay adhesion on IBH PCB error Relay: Poor contact, relay deformation, relay aging, etc. Triggering External factors : overcurrent, over high ambient temperature, etc. Relays and...
  • Page 148 M thermal Nature Series 6.30 C3, C4 Troubleshooting Digital display output Description Error code Current transformer failure or circuit Description C3≥3 times failure of IBH PCB Incorrect Dip switch S1, cables with IBH connected improperly; Triggering Overvoltage, IBH failure etc.
  • Page 149 M thermal Nature Series Procedure C3, C4 Confirm the Dip Switch S1 on main Correct Dip switch S1 control PCB, and it’s correct. The cables between IBH PCB(CN52) and Main Control PCB(CN9), the cables of Reconnect the cables securely tube heater is connected properly...

  • Page 150: Discharge / Suction Pressure And Temperature Range

    M thermal Nature Series 7 Discharge / Suction pressure and temperature range The following parameter ranges are used to roughly determine whether the system is running properly: Discharge temperature(Tp) on heating/DHW mode T4＜-10℃ Twout+10＜Tp＜Twout+30 Twout+10＜Tp＜Twout+30 -10℃≤T4＜10℃ Twout+10＜Tp＜Twout+25 10℃≤T4＜25℃ T4≥25℃ Twout+10＜Tp＜Twout+25...

  • Page 151: Appendix To Part 4

    M thermal Nature Series 8 Appendix to Part 4 8.1 Temperature Sensor Resistance Characteristics Applied to T3 Outdoor unit heat exchanger bottom temperature sensor T4 Ambient temperature sensor Th Return-air temperature sensor T2 Plate heat exchanger outlet refrigerant temperature sensor...
  • Page 152 M thermal Nature Series Temp. (°C) Resistance (kΩ) Temp. (°C) Resistance (kΩ) Rmax R（t）Normal Rmin Rmax R（t）Normal Rmin 10.8 10.473 10.147 2.004 1.883 1.766 10.3 1.934 1.816 1.702 9.848 9.551 9.255 1.867 1.752 1.641 9.418 9.125 8.834 1.802 1.69 1.582 9.01...
  • Page 153 M thermal Nature Series Applied to Tp Discharge temperature sensor R90℃=5KΩ±3%，B25/50=3950K±3% Temp. (°C) Resistance (kΩ) Temp. (°C) Resistance (kΩ) Rmax R（t）Normal Rmin Rmax R（t）Normal Rmin 2002.628 1642.059 1281.49 318.604 271.634 224.664 1881.964 1544.968 1207.972 302.08 257.867 213.653 1769.292 1454.213 1139.134 286.483...
  • Page 154 M thermal Nature Series Temp. (°C) Resistance (kΩ) Temp. (°C) Resistance (kΩ) Rmax R（t）Normal Rmin Rmax R（t）Normal Rmin 65.58 58.228 50.877 11.858 11.134 10.411 62.678 55.724 48.77 11.432 10.749 10.066 59.919 53.34 46.762 11.024 10.38 9.735 57.295 51.071 44.847 10.632 10.024...
  • Page 155 M thermal Nature Series Temp. (°C) Resistance (kΩ) Temp. (°C) Resistance (kΩ) Rmax R（t）Normal Rmin Rmax R（t）Normal Rmin 3.045 2.901 2.758 1.625 1.511 1.397 2.962 2.819 2.676 1.586 1.473 1.36 2.881 2.739 2.597 1.548 1.436 1.324 2.802 2.662 2.521 1.511 1.401...
  • Page 156 M thermal Nature Series Applied to TW_in Plate heat exchanger inlet water temperature sensor TW_out Plate heat exchanger outlet water temperature sensor T5 Water tank temperature sensor TW2 Zone 2 water flow temperature sensor R50=17.6KΩ±3%，B0/100=3970K±2% Temp. (°C) Resistance (kΩ) Temp. (°C) Resistance (kΩ)
  • Page 157 M thermal Nature Series Temp. (°C) Resistance (kΩ) Temp. (°C) Resistance (kΩ) Rmax R（t）Normal Rmin Rmax R（t）Normal Rmin 53.854 51.165 48.476 10.231 9.818 9.405 51.485 48.959 46.432 9.887 9.481 9.075 49.234 46.86 44.486 9.556 9.157 8.758 47.094 44.863 42.632 9.237 8.846...
  • Page 158 M thermal Nature Series Temp. (°C) Resistance (kΩ) Temp. (°C) Resistance (kΩ) Rmax R（t）Normal Rmin Rmax R（t）Normal Rmin 2.787 2.606 2.425 1.477 1.364 1.251 2.711 2.533 2.356 1.44 1.329 1.219 2.637 2.463 2.288 1.405 1.296 1.187 2.565 2.394 2.224 1.37 1.264...
  • Page 159 M thermal Nature Series 8.2 Pressure and Output voltage characteristics of Pressure sensor Pressure and Output voltage characteristics of Pressure sensor 5.00 Low pressure sensor High pressure sensor 4.50 y = 2x + 0.5 y = 0.87x + 0.5 4.00 3.50...
  • Page 160 M thermal Nature Series 8.3 Guide for identifying inverter PCB failure Before measuring the inverter PCB, please confirm steps below in advance : 1) Cut off the power supply ; 2) Wait for 10 mins for capacitor discharging in order to avoid the electric shock 3) Remove all connections wires 4) To identify whether inverter PCB of 1Ph models failed, follow the guide to test inverter circuit.
  • Page 161 M thermal Nature Series Inverter circuit (Fan module/ Compressor module): Test point Order Normal Abnormal +(Red) -（Black） 0.3-0.7V 0 /infinate Note: 1. If any one of test value abnormal, the inverter PCB failed. Request aftersales service and replace the inverter control box.

  • Page 162: General Information

    Midea will introduce a new generation of heat pumps that operate using R290 refrigerant. Theoretically, R290 is a highly flammable A3 refrigerant, but its risk can be effectively eliminated through product design and various aspects of control. This refrigerant has also been widely used in air conditioners, refrigerators, heat pumps, and other products in recent years.

  • Page 163: Transportation Precautions

    Transportation precautions Warehouse management requirements Transportation regulations: ADR, IMDG, IATA Only desk telephones will be set up for ADR regulations: Equipment containing less than 12 kg of communication within the warehouse. No mobile flammable refrigerant is not subject to transportation regulations if phones are allowed.
  • Page 164 sides of the unit and the wall should be more than 65 cm, the bottom of the unit must be more than 1.8 m above the ground, Tools required and an installation height of more than 15 cm should be When performing pipeline welding or maintained on the top of the heat pump.
  • Page 165 Postal code: 528311 mbt.midea.com / global.midea.com Midea reserves the right to change the specifications of the product, and to withdraw or replace products without prior notification or public announcement. Midea is constantly developing and improving its products. Please note that all the pictures in the document are for reference only. Actual products may vary.

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