Mitsubishi Heavy Industries SRRM40HENG-L, Handbook, Page: 263 / 1106

SCM-C
261
Abnormality of thermistor Disconnection of sensor and defective connection of connector
Chart for thermistor (Th
1
,
2
) temperature resistance characteristics
Is connection to connector
good?
Is thermistor resistance
value normal?
Replace PCB.
Repair connector.
Replace thermistor.
No
No
Yes
Yes
Indicator lamp of
indoor unit does not
illuminate.
Check receptacle voltage.
Check if PCB fuse is blown.
Check varister.
Check transformer secondary
voltage.
Replace PCB.
Yes
Replace fuse.
Replace varister.
Replace transformer.
No
CNC red – red·approx. 12V AC
(2) Indication of Self Diagnosis (Indoor unit)
TIMER lamp
is lights
continuously
RUN lamp is flashing.
(1 Time/8 sec.)
RUN lamp is flashing.
(2 Time/8 sec.)
RUN lamp is flashing.
(6 Time/8 sec.)
Connect of Defect
Abnormality of heat
exchanger thermistor.
Abnormality of room
temperature thermistor.
Abnormality of indoor
fan motor.
Place of defect
¡
Disconnection of heat exchanger thermistor.
¡
Disconnection of room temperature
thermistor.
¡
Fan motor is defective.
¡
Printed ciricuit board is defective.
(Disconnection)
(k
Ω
)
(Short circuit)
Temperature (
°
C)
Resistance value
Abnormality of indoor fan motor (Fan motor defective, printed circuit board defective)
No
Yes
Yes
The fan motor is defective.
Is the connector connection
good?
Repair the connector.
Is voltage being applied to the
fan motor? The indoor circuit board
is defective.
(3) Trouble Diagnostic Procedures
No