SiMX042215E
Troubleshooting
Part 6 Service Diagnosis
61
Reference
4.5 Thermistor or Related Abnormality (Indoor Unit)
Error Code
C4, C9
Method of Error
Detection
The temperatures detected by the thermistors determine thermistor errors.
Error Decision
Conditions
The voltage between the both ends of the thermistor is either 4.96 V or more, or 0.04 V or less
with the power on.
Supposed
Causes
Disconnection of connector
Defective thermistor(s)
Defective indoor unit PCB
Troubleshooting
C4
: Indoor heat exchanger thermistor
C9
: Room temperature thermistor
Check No.01
Refer to P.90
YES
(R21
8
70)
N
O
Check No. 01
Check the thermistor resistance
v
al
u
e.
YES
N
O
Caution
Correct the connection.
Replace the defecti
v
e
thermistor.
Replace the indoor
u
nit PCB
(control PCB).
N
ormal?
N
ormal?
Check the connection of
connectors.
Be s
u
re to t
u
rn off the po
w
er s
w
itch
b
efore connecting or disconnecting
connectors, or parts may
b
e damaged.
