Mitsubishi Heavy Industries V Multi FDC71VNX Technical Manual page 135

1.11 MAINTENANCE DATA
1.11.1 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
Error code Red LED Red LED
Stays OFF
Stays OFF Stays OFF 2-time flash Stays OFF Indoor unit power source • Power OFF, broken wire/blown fuse, broken transformer wire
No-indication 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
1-time
flash
Keeps
flashing
1-time
flash
Stays OFF
Keeps
flshing
3-time
flash
1(2)-time
flash
1-time
flash
1-time
flash
1(2)-time
flash
1-time
flash
Stays OFF
Notes (1) Normal indicator lamp (Indoor, outdoor units: 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 definitely, and, if the trouble is repaired by replacing
the part, it is judged consequently that the replaced part was defective.
Outdoor control PCB
Location of
Green Green
trouble
Red LED
LED (1) LED (1)
Keeps Keeps
Stays OFF —
flashing flashing
Remote control wires • Poor connection, breakage of remote control wire * For wire breaking at power ON, the LED is OFF.
Keeps Keeps
Stays OFF
flashing flashing
Remote control
Indoor-outdoor units
Keeps 2-time Keeps
connection wire
flashing flash flashing
Remote control
Remote control
*
wires (Noise)
Keeps Keeps
Stays OFF
flashing flashing
Remote control
indoor control PCB
Indoor-outdoor
Keeps 2-time Keeps
units connection
flashing flash flashing
wire
(Noise)
Keeps Keeps
Stays OFF
flashing flashing
Outdoor control
PCB
Outdoor control
Keeps Keeps
PCB
Stays OFF
flashing flashing
Fuse
Indoor heat
exchanger tempera-
Keeps Keeps
Stays OFF
ture sensor
flashing flashing
Indoor control PCB
Indoor return air
Keeps Keeps
temperature sensor
Stays OFF
flashing flashing
Indoor control PCB
Installation or oper-
ating condition
Indoor heat
Keeps Keeps
Stays OFF
exchanger tempera-
flashing flashing
ture sensor
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
Keeps Keeps Address setting
Stays OFF
flshing flshing error
Indoor unit No. setting •No master is assigned to slaves.
Keeps Keeps
Stays OFF
flashing flashing
Rcmote control wires •Anomalous remote control wire connection, broken wire between master and slave units
Indoor fan motor • Defective indoor 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 • Indoor unit operation check error
flashing flashing
Indoor fan motor • Indoor motor rotation speed anomaly
Keeps Keeps
Stays OFF
flashing flashing
Indoor power PCB • Defective indoor power PCB
Keeps Keeps Panel switch
Stays OFF
flashing flashing detection
Keeps Keeps Remote control
Stays OFF
temperature sensor
flashing flashing
Description of trouble
• Normal operation
• Defective remote control PCB
• Poor connection, breakage of indoor-outdoor units connection wire
• Improper setting of master and slave by remote control
• Poor connection of remote control signal wire (White)
• Intrusion of noise in remote control wire
*
• Defective remote control 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 source (defective com-
munication circuit)?
• Defective outdoor control PCB on the way of power source
• Blown fuse
• Defective indoor heat exchanger temperature sensor (defective element, broken
wire, short-circuit)
• Poor contact of temperature sensor connector
*
• Defective indoor control PCB (Defective temperature sensor input circuit)?
• Defective indoor return air temperature sensor (defective element, broken wire,
short-circuit)
• Poor contact of temperature sensor connector
*
• Defective indoor control PCB (Defective temperature sensor input circuit)?
• Heating over-load (Anomalously high indoor heat exchanger temperature)
• Defective indoor heat exchanger temperature sensor (short-circuit)
*
• Defective indoor control PCB (Defective temperature sensor 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 option parts (At optional anomalous input setting)
• When multi-unit control by remote control is performed, the number of units
is over
• Address setting error of indoor units
• Address setting error of master and slave indoor units
• Defective panel switch operation
• Broken wire of remote control temperature sensor
134
- -
'19 • PAC-T-327
Repair method
—
Repair
Repair
Replacement of
remote control
Repair
Repair
* For wire breaking at power ON, the LED is OFF
Replacement of remote
control or PCB
Repair
Power reset or
Repair
Replacement of
PCB
Replacement
Replacement, repair
of temperature
sensor
Replacement of PCB
Replacement, repair
of temperature
sensor
Replacement of PCB
Repair
Replacement of
temperature sensor
Replacement of PCB
Replacement, repair
of DM
Repair
Replacement of
PCB
Repair
Repair
Repair
Repair
Replacement, repair
Replacement
Repair
Repair
Replacement, repair
Replacement
Repair
Repair
Reference
page
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