Fdtc, Fde And Fdum Series; Diagnosing Of Microcomputer Circuit; Selfdiagnosis Function - Mitsubishi Heavy Industries SCM50ZS-S1 Technical Manual

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
Error code Red LED Red LED
Stays OFF
Stays OFF Stays OFF
No-indication Stays OFF
*
3-time
flash
or INSPECT I/
WAIT
Stays OFF
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
1-time
flash
1-time
flash
1-time
flash
Stays OFF
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 definitely, and, if the trouble is repaired by replacing
the part, it is judged consequently that the replaced part was defective.
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 control
*
• Defective remote control or indoor 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 control PCB
Keeps
flashing
*
• Occurrence of defective outdoor control PCB on the way of power source (defective communication
Outdoor control PCB
circuit)?
Outdoor control PCB • Defective outdoor control PCB on the way of power source
Keeps
flashing
Fuse • Blown fuse
• Defective indoor heat exchanger temperature sensor (defective element, broken wire,
Indoor heat exchanger tempera-
short-circuit)
ture sensor
Keeps
• Poor contact of temperature sensor connector
flashing
*
Indoor control PCB
• Defective indoor 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 control PCB
• Defective indoor 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 control PCB
• Defective indoor 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 control PCB (Defective float switch input circuit)
Indoor control PCB
*
• Defective indoor control PCB (Defective DM drive output circuit)?
Option • Defective option parts (At optional 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
• Address setting error of indoor units
flashing setting error
Fan motor • Defective fan motor
Keeps
flashing
Indoor control PCB • Defective indoor control PCB
Keeps
Indoor control PCB • Improper operation mode setting
flashing
Fan motor • Indoor fan motor rotation speed anomaly
Keeps
flashing
Indoor power PCB • Defective indoor power PCB
Keeps Remote control temperature
• Broken wire of remote control temperature sensor
flashing sensor
Description of trouble
* For wire breaking at power ON, the LED is OFF
215
- -
'18 • SCM-T-251
Reference
Repair method
—
Repair
Repair
Replacement of
remote control
Repair 236−240
Repair
Replacement of
remote control or
PCB
Repair
Power reset or
Repair
Replacement of
PCB
Replacement
Replacement,
repair of tem-
perature sensor
Replacement of
PCB
Replacement,
repair of tem-
perature sensor
Replacement of
PCB
Repair
Replacement
of temperature
sensor
Replacement of
PCB
Replacement,
repair of DM
Repair
(In case of FDTC, FDUM)
Replacement of
PCB
Repair
Repair
Repair
Replacement,
repair
Replacement
Repair
Replacement, repair
Replacement
Repair
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