Mitsubishi Heavy Industries SRK100VNXWZRF Service Manual page 29

1.2 MAINTENANCE DATA
1.2.1 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).
Note 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
( i ) Indoor unit
Remote control Indoor unit display
Error code Red LED RUN light TIMER light Red LED Green LED
ON
No-indication Stays OFF
—
—
or
WAIT
—
INSPECT I/U
—
ON
ON
ON
1-time
flash
Keeps
flashing
No-indication
3-time
flash
2-time
No-indication
flash
—
—
—
6-time
flash
—
Note *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 unit control PCB
Location of
trouble
Keeps
Stays OFF Stays OFF —
flashing
2-time Indoor unit power
Stays OFF
—
flash source
Remote control
wires
Keeps
—
Stays OFF
flashing
Remote control
Indoor-outdoor
units connection
2-time Keeps
—
wire
flash flashing
Remote control
Remote control
wires (Noise)
Keeps
Stays OFF
—
flashing
Remote control
indoor unit control PCB
Indoor-outdoor
6-time 2-time Keeps
units connection
flash flash
flashing
wire
(Noise)
Keeps
6-time
Stays OFF
flash flashing
Outdoor unit control
PCB
Outdoor unit control
6-time Keeps
PCB
Stays OFF
flash flashing
Fuse
Indoor heat
exchanger tempera-
6-time
ture sensor 1
ON Stays OFF
flash
Indoor unit control PCB •Defective indoor unit control PCB (Defective temperature sensor input
Indoor heat
exchanger tempera-
Keeps
ture sensor 2
ON Stays OFF
flashing
Indoor unit control PCB •Defective indoor unit control PCB (Defective temperature sensor input
Indoor room
air temperature
Keeps
sensor
ON Stays OFF
flashing
Indoor unit control PCB •Defective indoor unit control PCB (Defective temperature sensor input
Keeps Number of con-
— Stays OFF
flashing nected indoor units
Address setting
Keeps
— Stays OFF
flashing error
Indoor unit No. set-
Keeps
ting
— Stays OFF
flashing
Rcmote control wires •Anomalous remote control wire connection, broken wire between master and slave units
Fan motor
Keeps
ON Stays OFF
flashing
Indoor unit control PCB •Defective indoor unit control PCB
Remote control
Keeps
— Stays OFF temperature
flashing
sensor
Description of trouble
•Normal operation
•Power OFF, broken wire/blown fuse, broken transformer wire
•Poor connection, breakage of remote control wire * For wire breaking at power ON, the
LED is OFF.
• 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 unit 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 unit control PCB
*
•Occurrence of defective outdoor unit control PCB on the way of power source (defective
communication circuit)?
•Defective outdoor unit control PCB on the way of power source
•Blown fuse
•Defective indoor heat exchanger temperature sensor 1 (defective element, broken
wire, short-circuit)
• Poor contact of temperature sensor 1 connector
circuit)?
•Defective indoor heat exchanger temperature sensor 2 (defective element, broken
wire, short-circuit)
• Poor contact of temperature sensor 2 connector
circuit)?
•Defective room air temperature sensor (defective element, broken wire, short- circuit)
•Poor contact of temperature sensor connector
circuit)?
•When multi-unit control by remote control is performed, the number of
units is over
• Address setting error of indoor units
•No master is assigned to slaves.
•Defective fan motor
• Broken wire of remote control temperature sensor
28
- -
'22 • PAC-SM-422
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 1
Replacement of
PCB
Replacement, repair
of temperature
sensor 2
Replacement of
PCB
Replacement, repair
of temperature
sensor
Replacement of
PCB
Repair
Repair
Repair
Replacement, repair
Replacement
Repair
Reference
page
—
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