Mitsubishi Electronics MUZ-GB50VA service manual Check of outdoor thermistors

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•When OPERATION INDICATOR lamp flashes 6-time.

•When thermistor is abnormal.

B Check of outdoor thermistors

	Disconnect the connector in the outdoor electronic control P.C. board or the outdoor power board		No
			No		Replace the thermistor.
	(see below table), and measure the resistance of thermistor. Is the thermistor normal?				Replace the thermistor.


		Yes
		Yes

Reconnect the connector CN661, CN663 and CN3.

3 minutes after turning on the power supply, start EMERGENCY OPERATION.

Does the unit operate 10 minutes or more without	No
showing thermistor abnormality?
Yes
Normal

Replace the outdoor electronic control P.C. board.

	Thermistor	Symbol	Connector, Pin No.	Board
	Defrost	RT61	Between CN661 pin1 and pin2
	Discharge temperature	RT62	Between CN661 pin3 and pin4	Outdoor electronic control P.C. board
	Outdoor heat exchanger temperature	RT68	Between CN661 pin7 and pin8	Outdoor electronic control P.C. board
	Outdoor heat exchanger temperature	RT68	Between CN661 pin7 and pin8
	Ambient temperature	RT65	Between CN663 pin1 and pin2
	Fin temperature	RT64	Between CN3 pin1 and pin2	Outdoor power board

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Contents Revised EDITION-A R410A Refrigerant OBR01 ContentsMUZ-GA50VA E1 Technical ChangesSNB130FLDH SNB130FLDH1Accessories SpecificationPart Names and Functions MUZ-GB50VASpecifications and rating conditions of main electric parts Band Octave Noise Criteria CurvesMUZ-GB50VA Outdoor Unit Outlines and DimensionsOutdoor Unit MUZ-GB50VA Wiring DiagramUnitmm Refrigerant System DiagramIndoor Unit Outdoor Unit Performance CurvesCapacity and input curves MUZ-GB50VA Test RUN Operation How to operate fixed-frequency operationCool operation Performance Data Cool operation Rated frequency 79Hz MSZ-GB50VA MUZ-GB50VAOutdoor SHC SHF InputOutdoor DB Performance Data Heat operation Actuator ControlOutdoor fan motor control R.V. coil controlRelation between main sensor and actuator MUZ-GB50 TroubleshootingOFF Failure mode recall functionOperational procedure Outdoor unit failure mode table Time flash Communication error Lighting Indicator Instruction of troubleshootingOperation EmergencyOperate Lightning Twice Outdoor power system Troubleshooting check table MUZ-GB50VA Once Lighting RED BLK BLK WHT Trouble criterion of main parts MUZ-GB50VAWHT RED RED ORNTroubleshooting flow How to check inverter/ compressorCheck of outdoor thermistors Check of R.V. coil When heating operation does not workCheck of outdoor fan motor Check of power supplyCheck of LEV Check of current-limiting resistorParts side Electromagnetic noise enters into TV sets or radios Discharge temperature thermistor RT62 Noise filter P.C. board CN2 Outdoor power boardCN3 CN5MUZ-GB50VA Outdoor Unit Operating Procedure Photos Disassembly InstructionsRemoving the cabinet Photo Removing R.V. coil Operating Procedure PhotosRemoving outdoor fan motor Photo Ture thermistor and ambient temperature thermistorRemoving the reactor Removing the compressor and 4-way valve PhotoRoHS Parts List RoHS compliant MUZ-GB MUZ-GB50 MUZ-GB50VA Accessory