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SERVICE MANAUL Wall Mounted Type ON/OFF N-Series Model No. MMT09CABWCCC8 MMT12HABWCAM8 MMT09CDBWCCC8 MMT12HABWLCAM8 MMT12CDBWCCC8 MMT12HDBSCAM8 MMT12CDBSCAM8 MMT12HDBWCAM8 MMT12CDBWCAM8 MMT12HDBWLCAM8 MMT12CDBWLCAM8 MMT18HDBSCAM8 MMT18CDBWCCC8 MMT18HDBWCAM8 MMT18CDBSCAM8 MMT24CDBSCAM8 MMT18CDBWCAM8 MMT24CDBWCAM8 MMT12CABSCAM8 MMT24HDBSCAM8 MMT12CABWCAM8 MMT24HDBWCAM8 MMT12CABWLCAM8 MMT36CDBWLCAM8 MMT12HABSCAM8 MMT36HDBWLCAM8 MMT12CDBWLCCE8 MMT24CDBWLCCE8 MMT12CDBSCCE8 MMT09CDBWLCAE8 WARNING This service information is designed for experienced repair technicians only and is not designed for use by the general public.
Contents 1.Introduction..................... 1 2.Features ....................6 3.Sensors list ..................... 7 4.Pinping diagrams ..................8 5.Functions and control ................9 6.Electrical Parts test ................15 7.Service Diagnosis ................. 18 Domestic air conditioner...
Introduction 1. Introduction 1.1 Safety Cautions Be sure to read the following safety cautions before conducting repair work. The caution items are classified into “Warning” and “Caution”. The “Warning” items are especially important since they can lead to death or serious injury if they are not followed closely. The “Caution” items can also lead to serious accidents under some conditions if they are not followed.
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Introduction Warning Do not repair the electrical components with wet hands . Working on the equipment with wet hands can cause an electrical shock Do not clean the air conditioner by splashing water. Washing the unit with water can cause an electrical shock.
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Introduction Warning Be sure to use an exclusive power circuit for the equipment, and follow the technical standards related to the electrical equipment, the internal wiring regulations and the instruction manual for installation when conducting electrical work. Insufficient power circuit capacity and improper electrical work can cause an electrical shock or fire. Be sure to use the specified cable to connect between the indoor and outdoor units.
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Introduction Caution Installation of a leakage breaker is necessary in some cases depending on the conditions of the installation site, to prevent electrical shocks. Do not install the equipment in a place where there is a possibility of combustible gas leaks. If a combustible gas leaks and remains around the unit, it can cause a fire.
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Introduction Caution Check to see if the parts and wires are mounted and connected properly, and if the connections at the soldered or crimped terminals are secure. Improper installation and connections can cause excessive heat generation, fire or an electrical shock. If the installation platform or frame has corroded, replace it.
Features 2.Features 4 Fan setting :Select the fan speed LO,MED,HI,AUTO Anti-mold filter: Catches most small particles and remove unpleasant odors effectively. Sleep mode: The setting temperature and the indoor noise can be adjusted to a more comfortable level when you set the “sleep mode” during night sleep. 24Hour timer: Use the timer function to set on,or off,or from on to off,or from off to on Auto restart: Automatic return to previous operation conditions after sudden power blackout Easy clean design: The panel is easy to wash and the airflow vents can be detached easily...
Sensors list 3.Sensors list 3.1 Indoor unit type Description s ’ t Pipe sensor It’s used for detecting temperature of evaporator 3.2 Outdoor unit type Description i t c Its used for detecting suction pipe temperature of compressor Suction sensor to adjust gas flowing Domestic air conditioner...
Functions and control 5.Functions and control 5.1 Main functions and control specifications Including brief introduction to air conditioners of series models and electric control function. 5.1.1 Automatic running (1) Single cold automatic run mode: First entering into this mode, the main control “MCU” determines the corresponding work pattern according to the indoor temperature between cooling mode and blowing mode.
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Functions and control temperature control precision: 1 compressor can’t be controlled by temperature sensor within 2 minutes after it starts. control character: when Tr Ts, outlet air from compressor is on and indoor fan motor run at fixed wind speed. When Tr Ts, outlet air from compressor is off , and when Tr >...
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Functions and control State1 State2 State3 Ts-1 Ts+2 Ts+2 When all the ranges alternate, there is ±1 difference. 5.1.5 Heating mode: (cooling only have no the mode) *Temperature control range : 16 —30 *Temperature control precision: 1 *Control Character: When Tr Ts, compressor, four-ways valve and outdoor fan motor is on, indoor fan motor runs as in cold blast mode, and 4 of compensation is added after compressor is started.
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Functions and control 23 , fan motor enter breeze mode; and if the temperature of coil pipe is below 20 , fan motor stops running. 5.1.5.2 High temperature protection and high temperature expiration protection: 5.1.5.2.1 High temperature prevention: When the temp. of coil pipe is above 56 , the outdoor fan motor stops.
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Functions and control 5.1.6 Timer function: You can set 24-hour timer on or timer off as required, and the minimum time unit is 1 minute. After setting, the indicator of indoor unit is on , and it is off when timer setting is completed. There are several timer mode as follows. 5.1.6.1 Timer on: The LED of “timer on”...
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Functions and control 5.1.8.2 If the switch is kept pressed for 5 seconds, buzzer ring two times and unit enter enter test run mode. 5.1.8.3 Press the switch again, and then closes. 5.1.8.4 Enter emergency operation from timer mode, then timer is cancelled. 5.1.9 Test run: 5.1.9.1 The temperature sensor of inlet air doesn’t work, and compressor starts (but subject to the limit of -minute delay excluding the first time), and high wind, cooling, and air door is open.
Electrical Parts test 6.Electrical Parts test 6.1. AC fan motor Resistance value for AC fan motor M: main winding, the resistance between red and black A: accessory winding, the resistance between black and white Rrb+Rbw=Rrw 6.2. DC fan motor The voltage between red pin and black pin is DC 310V; The voltage between white wire and black pin is DC 15V;...
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Electrical Parts test 6.3.Compressor For fixed frequency compressor: Main Winding : CR Aux. Winding : CS RRS>RCR>RCS; RCR+RCS=RRS For DC inverter compressor: RU-V=RU-W=RV-W 6.4. Electronic expansion valve R1-4=48±4Ω R1-6=48±4Ω R2-3=48±4Ω R2-5=48±4Ω. Domestic air conditioner...
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Electrical Parts test 6.5. Step motor 1. The resistance between the red wire and any other wire is the same and the value is 200-300Ω approx. The resistance between: Red and Orange is 200-300Ω approx; Red and Yellow is 200-300Ω approx; Red and Purple is 200-300Ω...
Service Diagnosis 7. Service Diagnosis 7.1. No cooling diagnoses Power on the unit check whether the unit The indoor PCB or wire connection is fault, couldn’t start normal please check and repair Repair the fault according to the error Check whether there is an error codes codes diagnoses process displaying Keep pressing the emergency button about...
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Service Diagnosis Check whether the outdoor motor is running The outdoor fan motor or outdoor PCB fault, abnormal? please check and repair. Charge the refrigerant into system to the Check whether the outdoor system pressure pressure regain.(0.8-1.2MPa) is abnormal? There is some dust or water into the system, Check whether there is frosting near the please clean the system and recharge the gas.
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Service Diagnosis 7.3 Caution for Diagnosis The operation lamp flashes when any of the following errors is detected. 1. When a protection device of the indoor or outdoor unit is activated or when the thermistor malfunctions, disabling equipment operation. 2. When a signal transmission error occurs between the indoor and outdoor units. In either case, conduct the diagnostic procedure described in the following pages.
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Service Diagnosis 7.5.1 Thermistor or Related Abnormality Indoor Display E1: Room temperature sensor failure E2: Heat-exchange sensor failure Method of The temperatures detected by the thermistors are used to determine thermistor errors Malfunction Detection Malfunction when the thermistor input is more than 4.92V or less than 0.08V during compressor Conditions Note: The values vary slightly in some models Supposed...
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Service Diagnosis 7.5.2 EEPROM abnormal Indoor Display E4: indoor EEPROM error Method of The Data detected by the EEPROM are used to determine MCU Malfunction Detection Malfunction when the data of EEPROM is error or the EEPROM is damaged Decision Conditions Supposed Faulty EEPROM data...
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Service Diagnosis 7.5.3 Indoor AC fan motor malfunction Indoor Display Method of The rotation speed detected by the Hall IC during fan motor operation is used to determine Malfunction abnormal fan motor operation Detection Malfunction when the detected rotation feedback signal don’t received in 2 minutes Decision Conditions ■...
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Service Diagnosis 7.5.4 Refrigerant leaking detection Indoor Display FE : Refrigerant leaking detection malfunction Method of The temperatures variation detected by the thermistors are used to determine Malfunction refrigerant leaking. Detection Malfunction On off model refrigerant leaking detection : this function only works under Decision cooling mode.
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Service Diagnosis cooling Switching cooling mode mode? Is if compressor Troubleshoot the started? compressor Is if solenoid valve Open the valve open? there Refrigerant leak Repair welding leakage points Add refrigerant FE failure eliminated 4/5000 Domestic air conditioner...
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