8.2 FDTC, FDE and FDUM series
8.2.1
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 control error code,
indoor/outdoor unit green LED (power pilot lamp and microcomputer normality pilot lamp) or red LED (check pilot lamp).
(i) Indoor unit
Remote control
Indoor 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
234
*
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
235
Remote control • Defective remote control PCB
Replacement of
remote control
or INSPECT I/
U
Stays OFF
Keeps
flashing
Indoor-outdoor units connection
wire
• Poor connection, breakage of indoor-outdoor units connection wire
Repair
236−240
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
241
Remote control indoor control
PCB
*• Defective remote control or indoor 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
242
2-time
flash
Keeps
flashing
(Noise) • CPU-runaway on outdoor control PCB
Power reset or
Repair
Outdoor control PCB
*• Occurrence of defective outdoor control PCB on the way of power source (defective communication
circuit)?
Replacement of
PCB
2-time
flash
Keeps
flashing
Outdoor control PCB • Defective outdoor control 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-circuit)
• Poor contact of temperature sensor connector
Replacement,
repair of tem
-
perature sensor
243
Indoor control PCB
*• Defective indoor 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 tem
-
perature sensor
244
Indoor control PCB
*• Defective indoor 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
245
Indoor heat exchanger tempera-
ture sensor
• Defective indoor heat exchanger temperature sensor (short-circuit)
Replacement
of temperature
sensor
Indoor control PCB
*• Defective indoor 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
246
Float switch • Anomalous float switch operation (malfunction) Repair
Indoor control PCB
*• Defective indoor control PCB (Defective float switch input circuit)
*• Defective indoor control PCB (Defective DM drive output circuit)?
Replacement of
PCB
Option • Defective option parts (At optional 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
247
Keeps
flashing
Keeps
flashing
Address
setting error
• Address setting error of indoor units Repair
248
1-time
flash
Keeps
flashing
Fan motor • Defective fan motor
Replacement,
repair
249
Indoor control PCB • Defective indoor control PCB Replacement
1-time
flash
Keeps
flashing
Indoor control PCB • Improper operation mode setting Repair
250
1-time
flash
Keeps
flashing
Fan motor • Indoor fan motor rotation speed anomaly
Replacement, repair
251
Indoor power PCB • Defective indoor power PCB Replacement
Stays OFF
Keeps
flashing
Remote control temperature
sensor
• Broken wire of remote control temperature sensor Repair
252
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.
(In case of FDTC, FDUM)
-
215
-
'18 • SCM-T-251
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