Maintenance Data - Mitsubishi Electric FDT125VNVF Technical Manual

1.12 MAINTENANCE DATA

1.12.1 Diagnosing of microcomputer circuit
(1) Selfdiagnosis function
(a) Check Indicator Table
Whether a failure exists or not on the indoor unit and outdoor unit can be know by the contents of remote controller error code,
indoor/outdoor unit green LED (power pilot lamp and microcomputer normality pilot lamp) or red LED (check pilot lamp).
Note (1) SRK series only.
At the indoor unit side, errors are displayed with the combination of RUN light and TIMER light on the display panel.
(i) Indoor unit
1) FDT, FDTC, FDEN, FDU, FDUM, FDF series
Remote controller Indoor control PCB
Error code Red LED Red LED
Stays OFF
No-indication Stays OFF Stays OFF Stays OFF
*
3 times
flash
or
WAIT
Stays OFF
INSPECT I/U
Stays OFF
2 times
flash
2 times
flash
2 times
flash
1 time flash
1 time flash
Keeps
flashing
1 time flash
1 time flash
Stays OFF
3 times
flash
1(2) time
flash
1 time flash
1 time flash
Outdoor control PCB
Location of
Green Green
trouble
Red LED
LED (1) LED (1)
Keeps Keeps
Stays OFF —
flashing flashing
2 times Indoor unit power
Stays OFF
supply
flash
Remote controller
wires
Keeps Keeps
Stays OFF
flashing flashing
Remote controller • Defective remote controller PCB
Indoor-outdoor
units connection
Keeps 2 times Keeps
wire
flashing flash flashing
Remote controller • Improper setting of master and slave by remote controller
Remote controller
*
wires (Noise)
Keeps Keeps
Stays OFF
flashing flashing
Remote controller
indoor control PCB
Indoor-outdoor
Keeps 2 6 times Keeps
units connection
flashing flash flashing
wire
(Noise)
Keeps Keeps
Stays OFF
flashing flashing
Outdoor control
PCB
Outdoor control
Keeps
PCB
Stays OFF Stays OFF
flashing
Fuse
Indoor heat
exchanger tempera-
Keeps Keeps
ture thermistor
Stays OFF
flashing flashing
Indoor control PCB
Indoor return air
temperature therm-
Keeps Keeps
istor
Stays OFF
flashing flashing
Indoor control PCB
Installation or oper-
ating condition
Indoor heat
Keeps Keeps
Stays OFF exchanger tempera-
flashing flashing
ture thermistor
Indoor control PCB
Drain trouble
Float switch
Keeps Keeps
Stays OFF
flashing flashing
Indoor control PCB
Option
Keeps Keeps Number of con-
Stays OFF
flashing flashing nected indoor units
Indoor unit No. set-
Keeps Keeps
ting
Stays OFF
flashing flashing
Rcmote controller wires •Anomalous remote controller wire connection, broken wire between master and slave units
Fan motor
Keeps Keeps
Stays OFF
flashing flashing
Indoor power PCB • Defective indoor power PCB
Keeps Keeps Address
Stays OFF
flashing flashing setting error
Keeps Keeps
Stays OFF Indoor control PCB • Improper operation mode setting
flashing flashing
Description of trouble
• Normal operation
• Power OFF, broken wire/blown fuse, broken transformer wire
• Poor connection, breakage of remote controller wire * For wire breaking at power ON, the
LED is OFF.
• Poor connection, breakage of indoor-outdoor units connection wire
• Poor connection of remote controller signal wire (White)
• Intrusion of noise in remote controller wire
*
• Defective remote controller or indoor control PCB (defective communication circuit)?
• Poor connection of wire between indoor-outdoor units during operation
(disconnection, loose connection)
• Anomalous communication between indoor-outdoor units by noise, etc.
• CPU-runaway on outdoor control PCB
*
• Occurrence of defective outdoor control PCB on the way of power supply (defective com-
munication circuit)?
• Defective outdoor control PCB on the way of power supply
• Blown fuse
• Defective indoor heat exchanger temperature thermistor (defective element, bro-
ken wire, short-circuit)
• Poor contact of temperature thermistor connector
*
• Defective indoor control PCB (Defective temperature thermistor input
circuit)?
• Defective indoor return air temperature thermistor (defective element, broken wire,
short-circuit)
• Poor contact of temperature thermistor connector
*
• Defective indoor control PCB (Defective temperature thermistor input
circuit)?
• Heating over-load (Anomalously high indoor heat exchanger temperature)
• Defective indoor heat exchanger temperature thermistor (short-circuit)
*
• Defective indoor control PCB (Defective temperature thermistor input circuit)?
• Defective drain pump (DM), broken drain pump wire, disconnected connector
• Anomalous float switch operation (malfunction)
*
• Defective indoor control PCB (Defective float switch input circuit)
*
• Defective indoor control PCB (Defective DM drive output circuit)?
• Defective optional parts (At optional anomalous input setting)
• When multi-unit control by remote controller is performed, the number of
units is over
•No master is assigned to slaves.
• Defective fan motor
• Address setting error of master and slave indoor units
327
- -
'12 • PAC-T-174
Repair method
—
Repair
Repair
Replacement of
remote controller
Repair
Repair
* For wire breaking at power ON, the LED is OFF
Replacement of
remote controller or
PCB
Repair
Power reset or
Repair
Replacement of
PCB
Replacement
Replacement, repair
of temperature
thermistor
Replacement of
PCB
Replacement, repair
of temperature
thermistor
Replacement of
PCB
Repair
Replacement of
temperature therm-
istor
Replacement of
PCB
Replacement, repair
of DM
Repair
Replacement of
PCB
Repair
Repair
Repair
Replacement, repair
Replacement
Repair
Repair
Reference
page
—
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