Mitsubishi FDUA125VNPWVH - Maintenance Data; Microcomputer Circuit Diagnosis

'22 • PAC-SM-412
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36
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(1) Selfdiagnosis function
(a) Check indicator table
Whether a failure exists or not on the indoor unit can be know by the contents of remote control error code, indoor unit
greenLED(powerpilotlampandmicrocomputernormalitypilotlamp)orredLED(checkpilotlamp).
(i) Indoor unit
Remote control Indoor unit control PCB
Location of trouble Description of trouble Repair method
Reference
page
Error code Red LED Red LED
Green
LED (1)
No-indication StaysOFF
StaysOFF
Keeps
flashing
—
• Normal operation
—
—
StaysOFF StaysOFF Indoor unit power source •PowerOFF,brokenwire/blownfuse,brokentransformerwire Repair 62
*
3-time
flash
Keeps
flashing
Remote control wires •Poorconnection,breakageofremotecontrolwire*ForwirebreakingatpowerON,theLEDisOFF. Repair
63
Remote control •DefectiveremotecontrolPCB
Replacement of
remote control
WAIT
or
INSPECTI/U
StaysOFF
Keeps
flashing
Indoor-outdoor units connection
wire
•Poorconnection,breakageofindoor-outdoorunitsconnectionwire
Repair
64-68
Remote control •Impropersettingofmasterandslavebyremotecontrol
Keeps
flashing
StaysOFF
*
Keeps
flashing
Remote control wires (Noise)
• Poor connection of remote control signal wire (White)
• Intrusion of noise in remote control wire
*
ForwirebreakingatpowerON,theLEDisOFF
Repair
69
Remote control indoor unit control
PCB
*•DefectiveremotecontrolorindoorunitcontrolPCB(defectivecommunicationcircuit)?
Replacement of
remote control or
PCB
2-time
flash
Keeps
flashing
Indoor-outdoor units connection
wire
• Poor connection of wire between indoor-outdoor units during operation
(disconnection, loose connection)
• Anomalous communication between indoor-outdoor units by noise, etc.
Repair
70
2-time
flash
Keeps
flashing
(Noise) • CPU-runaway on outdoor PCB
Power reset or
Repair
Outdoor unit PCB
*•OccurrenceofdefectiveoutdoorunitPCBonthewayofpowersource(defectivecommunicationcircuit)?
Replacement of
PCB
2-time
flash
Keeps
flashing
Outdoor unit PCB • Defective outdoor unit PCB on the way of power source
Replacement
Fuse • Blown fuse
1-time
flash
Keeps
flashing
Indoorheatexchangertempera
-
ture sensor
• Defective indoor heat exchanger temperature sensor(defectiveelement,brokenwire,short-cir-
cuit)
• Poor contact of temperature sensor connector
Replacement, repair
of temperature
thermistor
71
Indoor unit control PCB
*• Defective indoor unit control PCB (Defective temperature sensor input circuit)?
Replacement of
PCB
1-time
flash
Keeps
flashing
Indoor return air temperature
sensor
• Defective indoor return air temperature sensor (defectiveelement,brokenwire,short-circuit)
• Poor contact of temperature sensor connector
Replacement, repair
of temperature
thermistor
72
Indoor unit control PCB
*• Defective indoor unit control PCB (Defective temperature sensor input circuit)?
Replacement of
PCB
1-time
flash
Keeps
flashing
Installationoroperatingcondi
-
tion
• Heating over-load(Anomalouslyhighindoorheatexchangertemperature) Repair
73
Indoorheatexchangertempera-
ture sensor
• Defective indoor heat exchanger temperature sensor (short-circuit)
Replacement of
temperature therm
-
istor
Indoor unit control PCB
*• Defective indoor unit control PCB(Defectivetemperaturesensorinputcircuit)?
Replacement of
PCB
1-time
flash
Keeps
flashing
Draintrouble • Defective drain pump (DM), broken drain pump wire, disconnected connector
Replacement, repair
ofDM
74
Floatswitch • Anomalous float switch operation (malfunction) Repair
Indoor unit control PCB
*• Defective indoor unit control PCB(Defectivefloatswitchinputcircuit)
*• Defective indoor unit control PCB(DefectiveDMdriveoutputcircuit)?
Replacement of
PCB
Option • Defective option parts(Atoptionanomalousinputsetting) Repair
StaysOFF
Keeps
flashing
Number of connected indoor
units
• When multi-unit control by remote control is performed, the number of units is over Repair
75
StaysOFF
Keeps
flashing
Addresssettingerror •Addresssettingerrorofindoorunits Repaie
76
1(2)-time
flash
Keeps
flashing
Fanmotor • Defective fan motor Replacement, repair
77
Indoor unit power PCB • Defective indoor unit power PCB Replacement
1-time
flash
Keeps
flashing
Indoor unit control PCB • Improper operation mode setting Repair
78
1(2)-time
flash
Keeps
flashing
Fanmotor • Defective by rotation speed of fan motor Replacement, repair
79
Indoor unit power PCB • Defective indoor unit power PCB Replacement
StaysOFF
Keeps
flashing
Remote control temperature
sensor
• Broken wire of remote control temperature sensor Repair
80
2. MAINTENANCE DATA
2.1 Diagnosing of microcomputer circuit
Notes (1)
Normal indicator lamp (Indoor unit: Green) extinguishes (or lights continuously) only when CPU is anomalous. It keeps flashing in
any trouble other than anomalous CPU.
(2)*markinthedescriptionoftroublemeansthat,inordinarydiagnosis,itcannotidentifythecausedenitely,and,ifthetroubleisrepairedbyreplacing
thepart,itisjudgedconsequentlythatthereplacedpartwasdefective.