MrCool U-match MDUO1836 Service Manual
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MrCool U-match MDUO1836 Service Manual

Dc inverter u-match series for r410a unitary split air conditioner
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DC Inverter U-match Series for R410A
Unitary Split Air Conditioner SERVICE
MANUAL
Capacity: 24kBtu/h~60kBtu/h
Rate Frequency: 60Hz
Operation Range:
Cooling: 5°F(-15°C)~129.2℉(54℃)
Heating: -22°F (-30°C)~75.2°F (24°C)
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Summary of Contents for MrCool U-match MDUO1836

  • Page 1 DC Inverter U-match Series for R410A Unitary Split Air Conditioner SERVICE MANUAL Capacity: 24kBtu/h~60kBtu/h Rate Frequency: 60Hz Operation Range: Cooling: 5°F(-15°C)~129.2℉(54℃) Heating: -22°F (-30°C)~75.2°F (24°C)
  • Page 2 Safety Notice Before using the air conditioner, please first read the instruction manual. Before installing the air conditioner, please first read the instruction manual. Before repairing the air conditioner, please first read the technical service manual.

  • Page 3: Table Of Contents

    CONTENTS Safety Notice on Maintenance........................1 Safety Notice on Operation........................2 1. Product Introduction..........................3 1.1 Lists of Units................................. 3 1.2 Electrical Parameters............................5 2. Control................................ 6 2.1 Operation Mode..............................6 2.2 Control Mode................................ 8 2.3 Functions................................10 3. Troubleshooting............................. 14 3.1 Wiring Diagrams..............................14 3.2 PCB Layout................................17 3.3 Error Code................................26 3.4 Troubleshooting..............................27...

  • Page 4: Safety Notice On Maintenance

    DC Inverter U-match Series for R410A Unitary Split Air Conditioner Safety Notice on Maintenance PROHIBITED ： (1) Do not pierce or burn. (2) Please note that refrigerant may be odorless. (3) The appliance shall be stored in a room without continuously operating ignition sources (For example: open flames, an operating gas appliance or an operating electric heater).

  • Page 5: Safety Notice On Operation

    Universal Service Manual high speed; Otherwise personal injury may occur. (5) Measure the insulation resistance after maintenance. The resistance must be 1M or higher. Bad insulation may lead to electric shock. (6) Welding and cutting work must be done in a well-ventilated place. (7) Gas appliances, heaters and other fire sources should be kept away from the installation and maintenance site.

  • Page 6: Product Introduction

    MRCOOL Universal Service Manual 1. Product Introduction 1.1 Lists of Units 1.1.1 List of Outdoor Units Power Supply Model Appearance V/Ph/Hz 208/230V-1Ph-60Hz MDUO1836 MDUO1860 208/230V-1Ph-60Hz...
  • Page 7 MRCOOL Universal Service Manual 1.1.2 List of Indoor Units Power Supply Cooling/Heating Model Appearance Capacity (Btu/h) V/Ph/Hz Airhandler MDUI18024 24000/24000 208/230V-1Ph-60Hz Airhandler 36000/36000 208/230V-1Ph-60Hz MDUI18036 Airhandler 48000/48000 208/230V-1Ph-60Hz MDUI18048 Airhandler MDUI18060 54000/54000 208/230V-1Ph-60Hz Note: 1 Ton =12000Btu/h = 3.517kW...

  • Page 8: Electrical Parameters

    MRCOOL Universal Service Manual 1.2 Electrical Parameters Power supply Circuit breaker capacity Model V/Ph/Hz 208/230V-1Ph-60Hz MDUO1836 MDUO1860 208/230V-1Ph-60Hz Power Supply Fuse Capacity Circuit Breaker Capacity Model V/Ph/Hz MDUO1824 208/230V-1Ph-60Hz MDUO1836 208/230V-1Ph-60Hz MDUO1848 208/230V-1Ph-60Hz MDUO1860 208/230V-1Ph-60Hz...

  • Page 9: Control

    MRCOOL Universal Service Manual 2. Control 2.1 Operation Mode 2.1.1 Cooling Mode...
  • Page 10 MRCOOL Universal Service Manual 2.1.2 Heating Mode...

  • Page 11: Control Mode

    MRCOOL Universal Service Manual 2.2 Control Mode 2.2.1 Based Control 2.2.1.1 Compressor Control When cooling or heating mode is turned on, indoor fan will run for a while before the compressor starts. Under different modes, the compressor can only be stopped after running for some time (special cases excluded).
  • Page 12 MRCOOL Universal Service Manual and outdoor and indoor fan will both stop. When the temperature sensed by outdoor tube temperature sensor reaches the preset value of defrosting stop, system will quit defrosting. The 4-way valve will switch back to the heating condition, compressor and outdoor unit fan restart.

  • Page 13: Functions

    MRCOOL Universal Service Manual detected open for continuously a little time. Under discharge high temperature protection, system will be shut down and display error code E4. When discharge high temperature protection occurs, system will restore operation if the discharge high temperature sensor is detected to be reclosed within a few minutes after shutdown.
  • Page 14 MRCOOL Universal Service Manual By setting the Forcible mode dial codes of the condensing unit, the air conditioner can quickly increase the capacity output and ensure reliable operation in a short time, so as to meet the user's demand for the indoor temperature to quickly reach the set temperature.
  • Page 15 MRCOOL Universal Service Manual Level 1 (Default) Level 2 Level 3 2.3.5 Forced Defrost Control Press and hold "SW1" for about 5s to enter the first level menu of the debugging mode, the outdoor unit mainboard LED displayer flashes. Under the first level menu, short press "SW1" to switch various functions. After switching to "06", short press "SW2"...
  • Page 16 MRCOOL Universal Service Manual indicates that shut down the forced cooling / heating mode. And then short press "SW1" to save. During debugging, if no operation is performed within 10s, the debugging mode interface will be exited. 2.3.8 Thermostat Functions...

  • Page 17: Troubleshooting

    MRCOOL Universal Service Manual 3. Troubleshooting 3.1 Wiring Diagrams The following electric diagram is for reference only. Please refer to diagram sticked on the unit as the latest version. 3.1.1 Wiring Diagrams of ODUS Model: MDUO1836...
  • Page 18 MRCOOL Universal Service Manual Model: MDUO1860...
  • Page 19 MRCOOL Universal Service Manual 3.1.2 Wiring Diagrams of IDUs Model: MDUO18024036 Model: MDUO18048060...

  • Page 20: Pcb Layout

    MRCOOL Universal Service Manual 3.2 PCB Layout 3.2.1 Interface Indoor unit: Model: MDUI18024, MDUI18036, MDUI18048, MDUI18060, Mainboard Printing Interface Printing Interface AC-N（X2） Neutral wire input X9(G_SCAN) Indoor motor check AC motor high speed AC-L （X1） Live wire input X14(OFAN-H-OUT) output...
  • Page 21 MRCOOL Universal Service Manual Transformer Live X10(O_SCAN) 4-Way check X4(R) wire output Pinboard Printing Interface Printing Interface DC-MOTOR1 DC motor output COM2 DC motor control signal input...
  • Page 22 MRCOOL Universal Service Manual Outdoor unit: Model: MDUO18036、MDUO18060 Mainboard Printing Interface Printing Interface high pressure sensor AC-L Live wire input H-PRESS interface System pressure AC-N Neutral wire input protection interface HEAT_TI Chassis electric System high pressure heating belt protection interface 2.
  • Page 23 MRCOOL Universal Service Manual Electromagnetic valve COM7 Unit communication interface interface Electronic expansion GPRS communication valve interface interface Electronic expansion valve 1 interface COM-MANUA Thermostat interface Refrigerant heat dissipation Drive communication DC_MOTOR1 COMM1 DC motor output interface DC_MOTOR2 low pressure sensor...
  • Page 24 MRCOOL Universal Service Manual Communication terminal, same COMM Compressor V phase terminal with COMM1 Drive power supply terminal Compressor W phase terminal Programming interface (for DC-MOTOR1 DC fan terminal JTAG1 testing) Power discharge terminal (for DC-BUS1 testing) Model: MDUO1860 Printing...
  • Page 25 MRCOOL Universal Service Manual Filtering Board: Model: MDUO1836 ⑩ ⑩ ⑩ ⑩ ⑩ ⑩ ⑩ Printing Interface No. Printing Interface Power output neutral wire terminal AC-L Power input live wire terminal N-OUT (reserved) AC-N Power input neutral wire terminal N-OUT Power output neutral wire terminal...
  • Page 26 MRCOOL Universal Service Manual Filtering board ground wire terminal L-OUT1 Power output live wire terminal Filtering board grounding hole L-OUT Power output live wire terminal (reserved) DC-BUS Power discharge terminal (for testing) 3.2.2 IPM, PFC Testing Method 3.2.2.1Method of Testing IPM Module (1) Preparation before test: prepare a universal meter and turn to its diode option, and then remove the wires U, V, W of the compressor after it is powered off for one minute.
  • Page 27 MRCOOL Universal Service Manual...
  • Page 28 MRCOOL Universal Service Manual MDUO1860...

  • Page 29: Error Code

    MRCOOL Universal Service Manual 3.3 Error Code Error code Error Compressor high pressure protection Compressor low pressure protection Compressor air discharge high-temperature protection Condenser temperature sensor error Outdoor ambient temperature sensor error Discharge temperature sensor error ODU tube temperature sensor error...

  • Page 30: Troubleshooting

    MRCOOL Universal Service Manual 3.4 Troubleshooting 3.4.1 “E1” Compressor High Pressure Protection Error display: ODU mainboard LED displayer Error judgment condition and method: It is judged through the action of high pressure switch. If the high pressure switch is cut off, it is judged that high pressure is too high and the system stops operation for protection.
  • Page 31 MRCOOL Universal Service Manual Troubleshooting： 3.4.2 “E3” Compressor Low-pressure Protection, Refrigerant Shortage Protection, Refrigerant Recovery Mode Error display: ODU mainboard LED displayer Error judgment condition and method:...
  • Page 32 MRCOOL Universal Service Manual It is judged through the action of low pressure switch. If the low pressure switch is cut off, it is judged that low pressure is too low and the system stops operation for protection. Possible reason：...
  • Page 33 MRCOOL Universal Service Manual 3.4.3 “E4” Compressor Air Discharge High-temperature Protection Error display: ODU mainboard LED displayer Error judgment condition and method: Test the compressor discharge temperature through compressor discharge pipe and shell top temperature sensor. If the tested temperature value is higher than 115℃, the unit will stop for protection Possible reason：...
  • Page 34 MRCOOL Universal Service Manual Troubleshooting： 3.4.4 “F2” Condenser Temperature Sensor Error Error display: ODU mainboard LED displayer Error judgment condition and method: Sample the AD value of temperature sensor through temperature sensor detecting circuit and judge the range of AD value, If the sampling AD value exceeds upper limit and lower limit in 5 seconds continuously, report...
  • Page 35 MRCOOL Universal Service Manual Possible reason: ■Poor contact between temperature sensor and terminal in mainboard interface ■Temperature sensor is abnormal ■Detecting circuit is abnormal Troubleshooting： Note: Please refer to Appendix 1 for temperature and resistance of temperature sensor. the relation between 3.4.5 “F3”...
  • Page 36 MRCOOL Universal Service Manual Troubleshooting： Note: Please refer to Appendix 1 for temperature and resistance of temperature sensor. the relation between 3.4.6 “F4” Discharge Temperature Sensor Error Error display: ODU mainboard LED displayer Error judgment condition and method: Sample the AD value of temperature sensor through temperature sensor detecting circuit and judge the range of AD value, If the sampling AD value exceeds upper limit and lower limit in 5 seconds continuously, report the error.
  • Page 37 MRCOOL Universal Service Manual Troubleshooting： Note: Please refer to Appendix 1 for temperature and resistance of temperature sensor. the relation between 3.4.7 “F6” ODU Tube Temperature Sensor Error Error display: ODU mainboard LED displayer Error judgment condition and method: Sample the AD value of temperature sensor through temperature sensor detecting circuit and judge the range of AD value, If the sampling AD value exceeds upper limit and lower limit in 5 seconds continuously, report the error.
  • Page 38 MRCOOL Universal Service Manual Troubleshooting： Note: Please refer to Appendix 1 for temperature and resistance of temperature sensor. the relation between 3.4.8“EE” ODU Memory Chip Error Error display: ODU mainboard LED displayer Error judgment condition and method: If ODU mainboard cannot read the memory chip, this error will be reported.
  • Page 39 MRCOOL Universal Service Manual 3.4.9 “H4” Overload Error display: ODU mainboard LED displayer Error judgment condition and method: When condensing pressure is higher than the protection value, system will report overload protection. Possible reason: ■Cooling ODU heat exchanger is blocked or heat exchange is bad.
  • Page 40 MRCOOL Universal Service Manual Troubleshooting： Overload Outdoor heat exchanger is blocked Remove the obstacle Indoor heat exchanger is blocked . Remove the obstacle Ambient temperature is out of the Normal protection . No operation range need to handle it .
  • Page 41 MRCOOL Universal Service Manual Drive board compressor current sampling circuit element is damaged or drive chip current sampling AD terminal ■ is abnormal. Compressor is damaged. ■ Troubleshooting： 3.4.11 “H6” DC Fan Error Error display: ODU mainboard LED displayer Error judgment condition and method: Mainboard doesn’t receive the signal of outdoor fan within 30s after the outdoor fan starts up.
  • Page 42 MRCOOL Universal Service Manual Troubleshooting： 3.4.12 “H7” Driver Out-of-Step Protection Error display: ODU mainboard LED displayer Error judgment condition and method: During operation, it can’t detect the rotor position and stops output. Or the actual running speed differs too much from the set running speed. In each case, compressor runs out of step and system stops for protection.
  • Page 43 MRCOOL Universal Service Manual Troubleshooting：...
  • Page 44 MRCOOL Universal Service Manual 3.4.13 “HC” PFC Protection Error display: ODU mainboard LED displayer Error judgment condition and method: After power is connected, and drive chip received IPM lead F0 that is of low level, than it is IPM module malfunction.
  • Page 45 MRCOOL Universal Service Manual 3.4.14 “Lc” Startup Failure Error display: ODU mainboard LED displayer Error judgment condition and method: Check the error code on nixie tube of ODU main control board. If PJ is displayed, it indicates inverter compressor startup failure Possible reason: ■Poor contact of compressor UVW wire;...
  • Page 46 MRCOOL Universal Service Manual 3.4.15 “P0” Driver Reset Protection Error display: ODU mainboard LED displayer Error judgment condition and method: Drive board chip resets and starts initialization. After the drive board is energized for 5s, it detects that the chip resets again. In this case, it can be judged as drive chip reset protection.
  • Page 47 MRCOOL Universal Service Manual Troubleshooting： 3.4.17 “P6” Master Control and Driver Communication Error Error display: ODU mainboard LED displayer Error judgment condition and method: If there is no other malfunction and the communication between master control and driver is cut off for 30s, then it can be judged that the communication between master control and driver is faulted.
  • Page 48 MRCOOL Universal Service Manual Troubleshooting： 3.4.18 “P7” Driver Module Sensor Error Error display: ODU mainboard LED displayer Error judgment condition and method: If IPM or PFC module temperature is lower than the set protection value, then it can be judged that driver module sensor error occurs and system will shut down for protection.
  • Page 49 MRCOOL Universal Service Manual 3.4.19 “P8” Driver Module High Temperature Protection Error display: ODU mainboard LED displayer Error judgment condition and method: If IPM module temperature or PFC module temperature exceeds the set protection value, then it can be judged that driver module temperature is too high and system will shut down for protection.
  • Page 50 MRCOOL Universal Service Manual ■Drive board PFC current sampling circuit element is damaged or drive chip PFC current sampling AD terminal is abnormal. Troubleshooting： 3.4.21 “Pc” Driver Current Error Error display: ODU mainboard LED displayer Error judgment condition and method: After power charging, if offset voltage average is detected to exceed 12.5% of 1.65V in 1s, then it can be...
  • Page 51 MRCOOL Universal Service Manual 3.4.22 “PL” Bus Low-Voltage Protection Error display: ODU mainboard LED displayer Error judgment condition and method: When compressor is running and there is no other malfunction, if busbar voltage is lower than the set value for low voltage protection, then it can be judged that bus low-voltage protection occurs. System will shut down for protection.
  • Page 52 MRCOOL Universal Service Manual Troubleshooting： 3.4.24 “PU” Charge Loop Error Error display: ODU mainboard LED displayer Error judgment condition and method: When the charge loop starts to get charged and the busbar voltage cannot reach the set value in a certain period of time, then it can be judged that charge loop error exists.
  • Page 53 MRCOOL Universal Service Manual 3.4.25 “ee” Drive Memory Chip Error Error display: ODU mainboard LED displayer Error judgment condition and method: If power is connected but the drive board with memory chip cannot detect the memory chip or read the memory chip data correctly, then it can be judged that drive memory chip error exists.
  • Page 54 MRCOOL Universal Service Manual 3.4.27 “C4” ODU Jumper Cap Error Error display: ODU mainboard LED displayer Error judgment condition and method: If jumper cap model doesn‘t match with mainboard, report the error Possible reason: ■Jumper cap is not installed ■Jumper cap model is wrong ■Detecting circuit is abnormal...
  • Page 55 MRCOOL Universal Service Manual...
  • Page 56 MRCOOL Universal Service Manual 3.5 Failures Not Caused by Errors (1) If your air conditioner fails to function normally, please first check the following items before maintenance: Problem Cause Corrective measure If you turn off the unit and then immediately turn it on, in order to protect the compressor Please wait for a while.
  • Page 57 Check the above items and adopt the corresponding corrective measures. If the air conditioner continues to function poorly, please stop the air conditioner immediately and contact MRCOOL's authorized local service center. Ask our professional service staff to check and repair the unit.

  • Page 58: Maintenance

    MRCOOL Universal Service Manual 4. Maintenance 4.1 System Diagram First First level level EXV Thermal Thermal Expansion Expansion Valve Valve Second Second level level EXV Condensor Condensor One Way Way Valve Valve Low Pressure Pressure Switch Switch Evaporator Evaporator Accumulator...
  • Page 59 MRCOOL Universal Service Manual (6) Wait for 10min to see if the system pressure can remain unchanged. If the pressure increase, there may be leakage. (7) Slightly open the liquid valve and let some refrigerant go to the connection pipe to balance the pressure inside and outside of the connection pipe, so that air will not come into the connection pipe when removing the hose.

  • Page 60: Refrigerant Charging

    MRCOOL Universal Service Manual 4.3 Refrigerant Charging Pre-charging Step 1: Connect the high pressure gauge line to the valve of liquid pipe and connect the low pressure gauge line to the valve of gas pipe. Connect the middle gauge line to the vacuum pump. Power on the vacuum pump and perform vacuum drying.
  • Page 61 MRCOOL Universal Service Manual Step 1: Close the valve of refrigerant tank. First remove the pressure gauge lines and connect the outdoor unit to the indoor unit. Then reconnect the pressure gauge lines. Connect the low pressure gauge line to the other joint of gas valve and connect the high pressure gauge line to the liquid valve.

  • Page 62: Maintenance Of Major Components

    MRCOOL Universal Service Manual 4.4 Maintenance of Major Components 4.4.1 Replacement of thermostat Please refer to the instruction manual of thermostat XE70-00/E1. 4.4.2 How to replace the compressor 4.4.2.1 Diagnosis of compressor failure A. On condition that the unit can be started up Step 1: If the unit can be started up, then start it up to check the current of the faulted compressor.
  • Page 63 MRCOOL Universal Service Manual and you can feel the movement of the valve spool. In the last stage of the reset process, you will hear the click of the valve and feel its vibration. Electronic expansion Touch the electronic expansion valve: a.
  • Page 64 MRCOOL Universal Service Manual D- Connect to the exhaust side Caution! High temperature! Labels on the 4-way valve: D-connect to the exhaust side; E-connect to the evaporator of indoor unit; S-connect to the inhalation side of the liquid separator; C-connect to the condenser;...
  • Page 65 MRCOOL Universal Service Manual Refer to the following table for the resistance between any two terminals: UV Winding VW Winding WU Winding Compressor model resistance resistance resistance QXFT-F310zN450 0.79±7%Ω 0.79±7%Ω 0.79±7%Ω QXAU-F516zX440A Measure the earth resistance of each wiring terminal. The resistance should be above 10 megohm. If not, we can judge that the compressor is faulted inside.
  • Page 66 MRCOOL Universal Service Manual Make sure the rubber seals of the suction and exhaust openings of the compressor are in good condition. Make sure the electric box cover of the compressor is in good condition. NOTICE: Before replacement, make sure the nameplates and models of the compressors are identical.
  • Page 67 MRCOOL Universal Service Manual 2) Prepare welding rods. Prepare some welding rods of common specifications and some special welding rods that contain more than 5% silver. They are used to weld the compressor. The suction and exhaust openings of the compressor are all connected to copper-plated steel pipes, so we need to use special welding rods and solder;...
  • Page 68 MRCOOL Universal Service Manual 1) The axial direction of the compressor should not slant at an angle larger than 20° to the horizontal direction. 2) Prevent the compressor from falling. 3) Put a transparent container (over 150ml in volume) under the exhaust pipe to collect the compressor oil, thus we can see the oil quality.
  • Page 69 MRCOOL Universal Service Manual Note: When pouring the liquid from the separator, make sure the discharge pipe is at the lower position.Slant at an angle not larger than 20° Use a transparent container to collect the content inside the separator. Check its color, seal it well and return it to the factory for inspection.
  • Page 70 MRCOOL Universal Service Manual pressure above 25kgf. Close the big and small valves and keep the pressure of indoor and outdoor units for more than 12h. If the pressure remains unchanged, then start vacuum pumping; otherwise, check the system for leaks again.
  • Page 71 MRCOOL Universal Service Manual Step 4: Remove the screws on the drive board of the compressor. The screws are located in the white circles as shown above in the picture. Step 5: Replace with a new compressor drive board. Before replacement, apply some silica gel on the IPM module.

  • Page 72: Removal Of Major Components

    MRCOOL Universal Service Manual 4.5 Removal of Major Components 4.5.1 Removal of ODU Major Components Picture Name Function Through compression, the low pressure refrigerant occupies a less space. Compressor As its pressure and temperature both rise, it becomes high pressure and high temperature refrigerant.
  • Page 73 MRCOOL Universal Service Manual Picture Name Function Accumulator Flash refrigerant from liquid to gas It is used to transfer partial heat of the hot flow to the cold flow so that the Condenser flow temperature can reach the specified index. It is an energy exchanging device.
  • Page 74 MRCOOL Universal Service Manual Model: MDUO1836 Removal of front panel Note: Before removing the front panel, make sure power is cut off. Step Picture Work instruction Unscrew the screws of the  1. Remove the upper cover upper cover plate with a plate.
  • Page 75 MRCOOL Universal Service Manual Removal of front panel Note: Before removing the front panel, make sure power is cut off. Step Picture Work instruction Unscrew the screws that  connect the right side plate 5. Remove the right side plate.
  • Page 76 MRCOOL Universal Service Manual Removal of front panel Note: Before removing the front panel, make sure power is cut off. Step Picture Work instruction Fix the clasps on both sides  9. Install the front side plate. of the plate and tighten up the screws.
  • Page 77 MRCOOL Universal Service Manual Removal of compressor/gas liquid separator Note: Before removing the compressor/gas liquid separator, make sure there is no refrigerant in the pipeline and power is cut off. Step Picture Work instruction Weld the pipes that are ...
  • Page 78 MRCOOL Universal Service Manual Removal of compressor/gas liquid separator Note: Before removing the compressor/gas liquid separator, make sure there is no refrigerant in the pipeline and power is cut off. Step Picture Work instruction After replacing the  5. Install the new...
  • Page 79 MRCOOL Universal Service Manual Removal of 4-way valve Note: Before removing the 4-way valve, make sure refrigerant is fully discharged from the unit and power is cut off. Step Picture Work instruction Carefully unscrew the  1. Take off the coil of the screws of electromagnetic 4-way valve.
  • Page 80 MRCOOL Universal Service Manual Removal of 4-way valve Note: Before removing the 4-way valve, make sure refrigerant is fully discharged from the unit and power is cut off. Step Picture Work instruction Tighten the screws of the  4. Install the coil of 4-way coil of 4-way valve with a valve.
  • Page 81 MRCOOL Universal Service Manual Removal of fan and motor Note: Before removing the fan, make sure power is cut off. Step Picture Work instruction Use a screwdriver to  unscrew the bolt of motor. 3. Remove motor. Note: Motor wire should be first removed from the electric box.
  • Page 82 MRCOOL Universal Service Manual Removal of condenser Note: Before removing the condenser, make sure there is no refrigerant in the pipeline and power is cut off. Step Picture Work instruction Remove the upper, lower and  1. Remove the panels.
  • Page 83 MRCOOL Universal Service Manual Removal of condenser Note: Before removing the condenser, make sure there is no refrigerant in the pipeline and power is cut off. Step Picture Work instruction Loosen the securing screws  of condenser support. Take off 5.
  • Page 84 MRCOOL Universal Service Manual Removal of condenser Note: Before removing the condenser, make sure there is no refrigerant in the pipeline and power is cut off. Step Picture Work instruction Check whether each  component and connection 8. Check and open the upper wire is well connected.
  • Page 85 MRCOOL Universal Service Manual Removal of electronic expansion valve Note: Before removing the electronic expansion valve, make sure there is no refrigerant in the pipeline and power is cut off. Step Picture Work instruction Remove the fixed  block between 2.
  • Page 86 MRCOOL Universal Service Manual Removal of electronic expansion valve Note: Before removing the electronic expansion valve, make sure there is no refrigerant in the pipeline and power is cut off. Step Picture Work instruction Weld the  connection pipe of electronic expansion valve.
  • Page 87 MRCOOL Universal Service Manual Removal of electronic expansion valve Note: Before removing the electronic expansion valve, make sure there is no refrigerant in the pipeline and power is cut off. Step Picture Work instruction Check whether  each component and connection wire is well 7.
  • Page 88 MRCOOL Universal Service Manual Removal of front panel Note: Before removing the front panel, make sure power is cut off. Step Picture Work instruction Unscrew the screws of the  3. Remove the front grill. front grill with a screwdriver.
  • Page 89 MRCOOL Universal Service Manual Removal of front panel Note: Before removing the front panel, make sure power is cut off. Step Picture Work instruction Unscrew the screws of the  7. Remove the valve cover valve cover with a screwdriver.
  • Page 90 MRCOOL Universal Service Manual Removal of front panel Note: Before removing the front panel, make sure power is cut off. Step Picture Work instruction Tighten up the screws  11. Install the upper cover plate. around the upper cover plate.
  • Page 91 MRCOOL Universal Service Manual Model: MDUO1860 Disassembly of compressor Note: Before removing the compressor, make sure there is no refrigerant in the pipeline and power is cut off. Step Picture Work instruction Loosen the securing screws  of the wires with a screwdriver.
  • Page 92 MRCOOL Universal Service Manual Disassembly of compressor Note: Before removing the compressor, make sure there is no refrigerant in the pipeline and power is cut off. Step Picture Work instruction Take out the compressor  and replace it. 4. Remove the compressor Note: When replacing the from the chassis.
  • Page 93 MRCOOL Universal Service Manual Disassembly of compressor Note: Before removing the compressor, make sure there is no refrigerant in the pipeline and power is cut off. Step Picture Work instruction Connect the compressor  wires to the wire terminals on the top of compressor.
  • Page 94 MRCOOL Universal Service Manual Removal of 4-way valve Note: Before removing the 4-way valve, make sure refrigerant is fully discharged from the unit and power is cut off. Step Picture Work instruction Use a soldering gun to  loosen the 4 joints on the...
  • Page 95 MRCOOL Universal Service Manual Model: MDUO1860 Removal of fan and motor Note: Before removing the fan, make sure power is cut off. Step Picture Work instruction Use a screwdriver to  unscrew the two screws on 1. Remove the grill.
  • Page 96 MRCOOL Universal Service Manual Removal of fan and motor Note: Before removing the fan, make sure power is cut off. Step Picture Work instruction Replace with a new motor.  4. Install the motor. Then tighten up the screw bolt.
  • Page 97 MRCOOL Universal Service Manual Model: MDUO1860 Removal of gas liquid separator Note: Before removing the gas liquid separator, make sure there is no refrigerant in the pipeline and power is cut off. Step Picture Work instruction Remove the upper, lower and ...
  • Page 98 MRCOOL Universal Service Manual Removal of gas liquid separator Note: Before removing the gas liquid separator, make sure there is no refrigerant in the pipeline and power is cut off. Step Picture Work instruction Install the gas liquid separator ...
  • Page 99 MRCOOL Universal Service Manual Model: MDUO1860 Removal of electronic expansion valve Note: Before removing the electronic expansion valve, make sure there is no refrigerant in the pipeline and power is cut off. Step Picture Work instruction Remove the upper, lower and ...
  • Page 100 MRCOOL Universal Service Manual Removal of electronic expansion valve Note: Before removing the electronic expansion valve, make sure there is no refrigerant in the pipeline and power is cut off. Step Picture Work instruction 4. Take out the electronic Take out the electronic ...
  • Page 101 MRCOOL Universal Service Manual Removal of electronic expansion valve Note: Before removing the electronic expansion valve, make sure there is no refrigerant in the pipeline and power is cut off. Step Picture Work instruction Check whether each  component and connection 7.
  • Page 102 MRCOOL ● Disconnect the electric element from the wiring terminal. ● Loosen screws around the electric 3. Remove the electric element. element with a screwdriver. ● Remove the electric element from the electric box. ● Place the electric element at the proper position.
  • Page 103 MRCOOL ● Disconnect the wires of the fan from the wiring terminal and draw them out. 2. Remove the fan. ● Loosen screws located at the front of the fan with a screwdriver. ● Remove the fan from the unit.
  • Page 104 MRCOOL ● Loosen screws round the lower panel 2. Remove the lower panel (1) with a screwdriver. and panel (2). ● Remove the lower panel from unit. ● Remove the screws from enhanced 3. Remove the enhanced frame frame. if applicable.
  • Page 105 MRCOOL 6. Remove the secondary drain ● Remove the secondary drain pan from pan. the unit. ● Remove the evaporator away from the 7. Remove the evaporator. primary drain pan. ● Reassemble the unit as before. Disassembly and Assembly of the Filter...

  • Page 106: Explosive View And Lists Of Parts

    MRCOOL Universal Service Manual 4.6 Explosive View and Lists of Parts 4.6.1 ODU Explosive View and Lists of Parts MDUO1836 29 30 31 34 35 36 37 Material name Coping Electric Box Assy PFC Inductance Filter Board Reactor Sub-Assy Power Switch...
  • Page 107 MRCOOL Universal Service Manual Inductance Terminal Board Terminal Board Radiator Main Board Condenser Assy Filter Sub-Assy Electromagnetic Valve Sub-Assy Magnet Coil (Electromagnetic Valve) Electromagnetic Valve Strainer Brushless DC Motor Axial Flow Fan Cabinet Diversion Circle Front Grill Front Side Plate...
  • Page 108 MRCOOL Universal Service Manual Pressure Protect Switch 4-Way Valve Pressure Sensor Rear Grill MDUO1860 27 28 29 30 31 36 37 Material name Coping Rear Grill Left Side Plate Electric Box Assy Drive Board Radiator Main Board Filter Board...
  • Page 109 MRCOOL Universal Service Manual Terminal Board Terminal Board Inductance Box Assy Handle Axial Flow Fan Cabinet Brushless DC Motor Gas-liquid Separator Sub-Assy Front Grill Front Side Plate Pressure Protect Switch Brushless DC Motor Electromagnetic Valve Electric Expand Valve Fitting Electric Expansion Valve Sub-Assy...
  • Page 110 MRCOOL Universal Service Manual 4.6.2 IDU Explosive View and Lists of Parts MDUO1836 Material name Coping Left Side Plate Electric Box Assy Terminal Board Transformer Terminal Board Main Board Terminal Board Pinboard Rear Side Plate...
  • Page 111 MRCOOL Universal Service Manual Centrifugal Fan Assy Motor For Centrifugal Fan Brushless DC Motor Top Cover Board Sub-Assy Bottom Cover Plate Assy Right Side Plate Bottom Cover Plate Assy Water Tray Strainer Cut-Off Valve 3/8(N) Thermal Expansion Valve Cut Off Valve...

  • Page 112: Appendices

    MRCOOL Universal Service Manual Appendices 1. Resistance/Temperature Lists of Temperature Sensors 1.1 Voltage List of 15 KΩ Temperature Sensors (including ODU temperature sensors) Temperature (℃) Temperature (℃) Resistance (kΩ) Voltage (V) Resistance (kΩ) Voltage (V) 0.311 2.523 2.825 138.1 0.323 2.439...
  • Page 113 MRCOOL Universal Service Manual Temperature (℃) Resistance (kΩ) Voltage (V) Temperature (℃) Resistance (kΩ) Voltage (V) 25.92 1.21 0.898 3.114 24.73 1.246 0.873 3.119 23.6 1.282 0.848 3.123 22.53 1.319 0.825 3.128 21.51 1.356 0.802 3.133 20.54 1.393 0.779 3.137 19.63...

  • Page 114: Voltage List Of 20 Kω Pipeline Temperature Sensors (Including Temperature Sensors For Defroster, Idu And Odu Pipes)

    MRCOOL Universal Service Manual Temperature (℃) Resistance (kΩ) Voltage (V) Temperature (℃) Resistance (kΩ) Voltage (V) 3.848 2.626 0.279 3.24 3.711 2.646 0.273 3.241 3.579 2.664 0.266 3.242 3.454 2.682 0.261 3.244 3.333 0.254 3.245 3.217 2.717 0.248 3.246 3.105 2.734...
  • Page 115 MRCOOL Universal Service Manual Temperature (℃) Resistance (kΩ) Voltage (V) Temperature (℃) Resistance (kΩ) Voltage (V) 76.24 0.686 1.658 3.047 72.41 0.714 1.609 3.054 68.79 0.743 1.561 3.061 65.37 0.773 1.515 3.068 62.13 0.804 1.47 3.074 59.08 0.835 1.427 3.08 56.19...

  • Page 116: Voltage List Of 50 Kω Discharge Temperature Sensors (Including Discharge Air Temperature Sensor)

    MRCOOL Universal Service Manual Temperature (℃) Resistance (kΩ) Voltage (V) Temperature (℃) Resistance (kΩ) Voltage (V) 10.2 2.185 0.4966 3.22 9.803 2.215 0.4845 3.222 9.42 2.243 0.4727 3.224 9.054 2.272 0.4613 3.226 8.705 2.299 0.4502 3.227 8.37 2.326 0.4394 3.229 8.051...
  • Page 117 MRCOOL Universal Service Manual Temperature (℃) Resistance (kΩ) Voltage (V) Temperature (℃) Resistance (kΩ) Voltage (V) 407.51 0.079 7.4702 1.889 384.51 0.084 7.2245 1.916 362.99 0.088 6.9882 1.943 342.83 0.094 6.7608 1.969 323.94 0.099 6.542 1.995 306.23 0.104 6.3315 2.021 289.61...
  • Page 118 MRCOOL Universal Service Manual Temperature (℃) Resistance (kΩ) Voltage (V) Temperature (℃) Resistance (kΩ) Voltage (V) 45.074 0.599 2.0148 2.747 43.163 0.621 1.9626 2.759 41.313 0.643 1.9123 2.77 39.61 0.665 1.8652 2.781 37.958 0.688 1.8158 2.793 36.384 0.711 1.7698 2.804 34.883...

  • Page 119: Temperature/Pressure List Of Refrigerant

    MRCOOL Universal Service Manual 2. Temperature/Pressure List of Refrigerant R410A Temperature Pressure Temperature Pressure Temperature Pressure ℃ ℃ ℃ 1880 1910 1960 2030 2080 2130 2180 2240 1020 2290 1050 2350 1090 2410 1110 2460 1150 2510 1180 2580 1220...

This manual is also suitable for:

U-match mduo1860U-match mduo1824U-match mduo1848U-match mdui18024U-match mdui18036U-match mdui18048 ... Show all

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