Mitsubishi Heavy Industries FDT90VNPWVH Service Manual page 48

2. MAINTENANCE DATA
2.1 FDT, FDU, FDUM, FDE series
2.1.1 Diagnosing of microcomputer circuit
(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
Error code Red LED Red LED
Stays OFF
No-indication Stays OFF
Stays OFF Stays OFF
*
3-time
flash
or
WAIT
Stays OFF
INSPECT I/U
Stays OFF
2-time
flash
2-time
flash
2-time
flash
1-time
flash
1-time
flash
Keeps
flashing
1-time
flash
1-time
flash
Stays OFF
Keeps
flashing
3-time
flash
1(2)-time
flash
1-time
flash
1-time
flash
Location of trouble
Green
LED (1)
Keeps
—
• Normal operation
flashing
Indoor unit power source • Power OFF, broken wire/blown fuse, broken transformer wire
Remote control wires • Poor connection, breakage of remote control wire * For wire breaking at power ON, the LED is OFF.
Keeps
flashing
Remote control • Defective remote control PCB
Indoor-outdoor units connection
• Poor connection, breakage of indoor-outdoor units connection wire
Keeps
wire
flashing
Remote control • Improper setting of master and slave by remote control
• Poor connection of remote control signal wire (White)
Remote control wires (Noise)
*
• Intrusion of noise in remote control wire
Keeps
flashing
Remote control indoor unit control
*
• Defective remote control or indoor unit control PCB (defective communication circuit)?
PCB
• Poor connection of wire between indoor-outdoor units during operation
Keeps Indoor-outdoor units connection
(disconnection, loose connection)
flashing wire
• Anomalous communication between indoor-outdoor units by noise, etc.
(Noise) • CPU-runaway on outdoor PCB
Keeps
flashing
*
Outdoor unit PCB
• Occurrence of defective outdoor unit PCB on the way of power source (defective communication circuit)?
Outdoor unit PCB • Defective outdoor unit PCB on the way of power source
Keeps
flashing
Fuse • Blown fuse
• Defective indoor heat exchanger temperature sensor (defective element, broken wire, short-cir-
Indoor heat exchanger tempera-
cuit)
ture sensor
Keeps
• Poor contact of temperature sensor connector
flashing
*
Indoor unit control PCB
• Defective indoor unit control PCB (Defective temperature sensor input circuit)?
Indoor return air temperature • Defective indoor return air temperature sensor (defective element, broken wire, short-circuit)
sensor • Poor contact of temperature sensor connector
Keeps
flashing
*
Indoor unit control PCB
• Defective indoor unit control PCB (Defective temperature sensor input circuit)?
Installation or operating condi-
• Heating over-load (Anomalously high indoor heat exchanger temperature)
tion
Keeps Indoor heat exchanger tempera-
• Defective indoor heat exchanger temperature sensor (short-circuit)
flashing ture sensor
*
Indoor unit control PCB
• Defective indoor unit control PCB (Defective temperature sensor input circuit)?
Drain trouble • Defective drain pump (DM), broken drain pump wire, disconnected connector
Float switch • Anomalous float switch operation (malfunction)
Keeps
*
flashing
• Defective indoor unit control PCB (Defective float switch input circuit)
Indoor unit control PCB
*
• Defective indoor unit control PCB (Defective DM drive output circuit)?
Option • Defective option parts (At option anomalous input setting)
Keeps Number of connected indoor
• When multi-unit control by remote control is performed, the number of units is over
flashing units
Keeps
Address setting error • Address setting error of indoor units
flashing
Indoor unit No. setting • No master is assigned to slaves.
Keeps
flashing
Rcmote control wires • Anomalous remote control wire connection. broken wire between master and slave units
Fan motor • Defective fan motor
Keeps
flashing
Indoor unit power PCB • Defective indoor unit power PCB
Keeps
Address setting error • Address setting error of master and slave indoor units
flashing
Keeps
Indoor unit control PCB • Improper operation mode setting
flashing
Description of trouble
* For wire breaking at power ON, the LED is OFF
47
- -
'19 • PAC-SM-334
Reference
Repair method
page
— —
Repair 73
Repair
74
Replacement of
remote control
Repair 75-79
Repair
80
Replacement of
remote control or
PCB
Repair
Power reset or
Repair
81
Replacement of
PCB
Replacement
Replacement, repair
of temperature
thermistor
82
Replacement of
PCB
Replacement, repair
of temperature
thermistor
83
Replacement of
PCB
Repair
Replacement of
temperature therm- 84
istor
Replacement of
PCB
Replacement, repair
of DM
Repair
85
Replacement of
PCB
Repair
Repair 86
Repaie 87
Repair 88
Replacement, repair
89
Replacement
Repair 90
Repair 91