Revision D: • RoHS PARTS LIST has been changed. SPLIT-TYPE, HEAT PUMP AIR CONDITIONERS Please void OB455 REVISED EDITION-C. OUTDOOR UNIT No. OB455 SERVICE MANUAL REVISED EDITION-D utilized R410A Wireless type Models MUZ-GB50VA - MUZ-GB50VA - Indoor unit service manual MSZ-GB·VA Series (OB454) Refrigerant service manual R410A REFRIGERANT (OBR01)
Revision A: • Compressor has been changed. Model RoHS PARTS LIST number Previous SNB130FLDH E12 851 900 SNB130FLDH1 E12 939 900 Revision B: • REFRIGERANT SYSTEM DIAGRAM has been changed. • Oil separator has been added. • Capillary tube has been added. ([1.8 [0.6 1000) •...
PART NAMES AND FUNCTIONS MUZ-GB50VA ACCESSORIES Air inlet (back and side) Piping MUZ-GB50VA Drain hose Drain socket Drain cap [33 Air outlet Drain outlet SPECIFICATION Outdoor model MUZ-GB50VA Cooling Heating Function Single phase Power supply 230V,50Hz 5.0(0.9-5.8) 5.8(0.9-7.8) Capacity Rated frequency(Min.-Max.) —...
OUTLINES AND DIMENSIONS MUZ-GB50VA Unit: mm REQUIRED SPACE Open as a rule 500 mm or more if the front and both sides are open 100 mm or more 200 mm or more if 100 mm or more there are obstacles to both sides Open as a rule 500 mm or more if the back,...
PERFORMANCE CURVES MUZ-GB50VA The standard specifications apply only to the operation of the air conditioner under normal conditions. Since operating condi- tions vary according to the areas where these units are installed, the following information has been provided to clarify the operating characteristics of the air conditioner under the conditions indicated by the performance curve.
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24.1 22.3 20.4 18.5 16.7 14.8 13.0 11.1 Outdoor intake air Wet-bulb temperature (:) Outdoor intake air Wet-bulb temperature (:) NOTE:The above broken lines are for the heating operation without any frost and defrost operation. 8-2. Capacity and input correction by operational frequency of compressor MUZ-GB50VA Correction of Cooling capacity Correction of Cooling total input...
8-4. OUTDOOR LOW PRESSURE AND OUTDOOR UNIT CURRENT NOTE: The unit of pressure has been changed to MPa based on the international system of units (SI unit system). The conversion factor is: 1(MPa [Gauge] = 10.2 (Kgf/f f [Gauge]) COOL operation Relative humidity(%) Dry-bulb temperature(:) 1 Both indoor and outdoor unit are under the...
9-3. Relation between main sensor and actuator Actuator Sensor Purpose Outdoor Compressor fan motor R.V. coil Discharge temperature thermistor Protection Indoor pipe temperature thermistor Defrosting Protection Defrost thermistor Defrosting Fin temperature thermistor Protection Outdoor heat exchanger temperature Protection Ambient temperature thermistor Protection TROUBLESHOOTING MUZ-GB50VA...
10-2. Failure mode recall function Outline of the function This air conditioner can memorize the abnormal condition which has occurred once. Even though LED indication listed on the troubleshooting check table (10-4.) disappears, the memorized failure details can be recalled. This mode is very useful when the unit needs to be repaired for the abnormality which doesn't recur.
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2. Flow chart of the detailed outdoor unit failure mode recall function Operational procedure The outdoor unit might be abnormal. Confirm if outdoor unit is abnormal according to the following procedures. Confirm that the remote controller is in the failure mode recall function.
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3. Outdoor unit failure mode table MUZ-GB50VA LED indication The left lamp of Indoor/outdoor Abnormal point OPERATION INDICATOR Condition Correspondence (Outdoor P.C. board) unit failure mode (Failure mode / protection) lamp (Indoor unit) recall function LED 1 LED 2 None (Normal) Outdoor power system 2-time flash Lighting Lighting...
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LED indication The left lamp of Indoor/outdoor Abnormal point (Outdoor P.C. board) Condition Correspondence OPERATION INDICATOR unit failure mode (Failure mode / protection) recall function lamp (Indoor unit) LED 1 LED 2 Communication error Communication error occurs between 11-time flash Lighting 6 times •...
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10-3. Instruction of troubleshooting Start OPERATION Indoor unit Indoor unit INDICATOR Indoor unit operates. operates. doesn't receive lamp on the indoor Outdoor unit doesn't Outdoor unit the signal from unit is flashing on operate normally. doesn't remote controller. and off. operate.
10-4. Troubleshooting check table MUZ-GB50VA Indication Symptom Abnormal point / Condition Condition Correspondence LED1(Red) LED2(Yellow) Outdoor unit • Check the connection of the compressor connecting Overcurrent protection stop is continuously performed 3 times within does not wire. 1 minute after the compressor gets started, or when converter protection operate.
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Indication No. Symptom Abnormal point / Condition Condition Correspondence LED1(Red) LED2(Yellow) Outdoor unit These symptoms do not mean any abnormality of the Primary current protection The input current exceeds 15A. Once Lighting operates. product, but check the following points. The current of the compressor exceeds 15A. Secondary current protection •...
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10-5. Trouble criterion of main parts MUZ-GB50VA Part name Check method and criterion Figure Defrost thermistor Measure the resistance with a tester. (RT61) Ambient temperature Refer to 10-7. “Test point diagram and voltage”,1. “Outdoor electronic thermistor (RT65) control P.C. board”, the chart of thermistor. Outdoor heat exchanger temperature thermistor (RT68)
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10-6. Troubleshooting flow MUZ-GB50VA A A How to check inverter/ compressor Disconnect the terminal of the compressor. 3 minutes after turning on the power supply, start EMERGENCY OPERATION. W • After the outdoor fan starts running, wait for 1 minute or more before Measure the voltage between each measuring the voltage.
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• When OPERATION INDICATOR lamp flashes 6-time. • When thermistor is abnormal. B B Check of outdoor thermistors Disconnect the connector in the outdoor electronic control P.C. board or the outdoor power board Replace the thermistor. W (see below table), and measure the resistance of thermistor. Is the thermistor normal? W When RT64 is abnormal, replace the outdoor power board.
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The cooling operation or heating operation does not operate. (LED display: Both LED1 and LED2 lighting) C C Check of R.V. coil • When heating operation does not work. 1. Disconnect the lead wire leading to the compressor. 2. 3 minutes after turning on the power supply, start EMERGENCY OPERATION in HEAT mode.
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• Fan motor does not operate or stops operating shortly after starting the operation. D D Check of outdoor fan motor Check the connection between the connector CN931 and CN932. Is the resistance between each terminal of outdoor fan motor normal? Disconnect CN932 from outdoor electronic control P.C.
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Outdoor unit does not operate at all, or stops immediately due to overcurrent. F F Check of current-limiting resistor When the current-limiting resistor is open, the rush current limiting relay (X64) may not work properly. Is the resistance of current-limiting Turn ON the power Replace the noise filter P.C.
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• When unit cannot operate neither by the remote controller nor by EMERGENCY OPERATION switch. Indoor unit does not operate. • When OPERATION INDICATOR lamp flashes ON and OFF every 0.5-second. Outdoor unit doesn’t operate. H H How to check miswiring and serial signal error (when outdoor unit does not work) Turn OFF the power supply.
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I I Electromagnetic noise enters into TV sets or radios Is the unit earthed? Earth the unit. Is the distance between the Extend the distance between antennas and the indoor the antennas and the indoor unit within 3m, or is the unit, and/or the antennas and distance between the the outdoor unit.
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10-7. Test point diagram and voltage 1. Outdoor electronic control P.C. board MUZ-GB50VA Defrost thermistor (RT61) Ambient temperature thermistor (RT65) Outdoor heat exchanger temperature thermistor (RT68) Fin temperature thermistor (RT64) Discharge temperature thermistor (RT62) 10 20 30 40 50 60 70 80 100 110 120 Temperature (°C) Temperature (;)
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2. Noise filter P.C. board MUZ-GB50VA CN901 To electronic CN902 CN903 control To power To power P.C. board board board 230V AC Input CN912 R.V. coil 230V AC 230V AC 230V AC Output Output F64 FUSE F911 FUSE NR64 VARISTOR 250V 2A 250V 1A...
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3. Outdoor power board MUZ-GB50VA Connect to the compressor Voltage among phases: 5V to 180V 325-370V DC Connect to the earth Output (Red) Connect to the controller board (–) (+)1-5(–): Signal transmission (To electronic control P.C. board) (White) 5V DC pulse wave (+)2-5(–): Zero cross signal : Not used (+)6-5(–): 15V...
DISASSEMBLY INSTRUCTIONS <"Terminal with locking mechanism" Detaching points> The terminal which has the locking mechanism can be detached as shown below. There are two types ( Refer to (1) and (2)) of the terminal with locking mechanism. The terminal without locking mechanism can be detached by pulling it out. Check the shape of the terminal before detaching.
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OPERATING PROCEDURE PHOTOS 2. Removing the inverter assembly, inverter P.C. board Photo 4 and power board Screws of the power board assembly (1) Remove the top panel, cabinet and service panel. (Refer to 1.) (2) Remove the back panel.(Refer to 1.) (3) Disconnect the following connectors;...
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OPERATING PROCEDURE PHOTOS 4. Removing the defrost thermistor, discharge temper- Photo 5 ature thermistor, outdoor heat exchanger tempera- Discharge temperature thermistor ture thermistor and ambient temperature thermistor (1) Remove the top panel, cabinet and service panel. (Refer to 1.) (2) Remove the back panel. (Refer to 1.) (3) Disconnect the following connectors;...
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OPERATING PROCEDURE PHOTOS 6. Removing the compressor and 4-way valve Photo 8 (1) Remove the top panel, cabinet and service panel. (Refer to 1.) (2) Remove the back panel. (Refer to 1.) (3) Remove the inverter assembly. (Refer to 2.) (4) Recover gas from the refrigerant circuit.
RoHS PARTS LIST (RoHS compliant) MUZ-GB50VA 12-1. OUTDOOR UNIT STRUCTURAL PARTS, ELECTRICAL PARTS AND FUNCTIONAL PARTS...
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MUZ-GB50VA 12-1. OUTDOOR UNIT STRUCTURAL PARTS, ELECTRICAL PARTS AND FUNCTIONAL PARTS Part numbers that are circled are not shown in the illustration. Q'ty/unit Symbol Part No. Part Name Remarks in Wiring MUZ-GB50VA - Diagram E12 819 297 TOP PANEL OUTDOOR HEAT EXCHANGER E12 851 630 E12 938 301 OUTDOOR FAN MOTOR...
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E12 444 705 DRAIN CAP HEAD OFFICE: TOKYO BLDG., 2-7-3, MARUNOUCHI, CHIYODA-KU, TOKYO 100-8310, JAPAN C C Copyright 2006 MITSUBISHI ELECTRIC ENGINEERING CO.,LTD Distributed in Sep. 2007. No. OB455 REVISED EDITION-D 6 Distributed in Jun. 2007. No. OB455 REVISED EDITION-C 6 Distributed in Apr.