Troubleshooting by Indication on the Remote Controller
SiUS28-902_B
100
Service Diagnosis
3.9
Heat Exchanger (Liquid pipe) Thermistor Abnormality
Remote
Controller
Display
C4
Applicable
Models
All indoor models
Method of Error
Detection
The error is detected by temperature detected by heat exchanger thermistor.
Error Decision
Conditions
When the heat exchanger thermistor becomes disconnected or shorted while the unit is running
Supposed
Causes
Defective thermistor for heat exchanger (liquid pipe)
Defective indoor unit PCB
Troubleshooting
Note:
Connector and indoor unit PCB
Refer to “Thermistor Resistance / Temperature Characteristics” table on P.161.
Connector
is connected to
the connector (
*
) of the
indoor
u
nit PCB.
Resistance
is normal
w
hen
meas
u
red after
disconnecting the thermistor
from the indoor
u
nit
PCB (3.5k
W
~
360k
W
)
Caution
Be s
u
re to t
u
rn off the po
w
er s
w
itch
b
efore connecting or disconnecting
the connector or parts may
b
e damaged.
Replace the indoor
u
nit PCB.
Connect the thermistor and t
u
rn
O
N
again.
N
O
N
O
Replace the thermistor (
*
).
YES
YES
Model
Connector for the heat exchanger (liquid pipe) thermistor
Symbol
PCB
FCQ
X12A
R2T
A1P
FHQ
X12A
R2T
A1P
FAQ
X18A
R2T
A1P
FTQ
X18A
R1T
A1P