Troubleshooting
SiBE041025
74
Service Diagnosis
4.18 Thermistor or Related Abnormality (Outdoor Unit)
Remote
Controller
Display
H9
,
J3
,
J6
,
P4
Method of
Malfunction
Detection
This fault is identified based on the thermistor input voltage to the microcomputer.
A thermistor fault is identified based on the temperature sensed by each thermistor.
Malfunction
Decision
Conditions
The thermistor input voltage is above 4.96 V or below 0.04 V with the power on.
J3
error is judged if the discharge pipe temperature is lower than the heat exchanger
temperature.
Supposed
Causes
Disconnection of the connector for the thermistor
Defective thermistor
Defective heat exchanger thermistor in the case of
J3
error (outdoor heat exchanger
thermistor in cooling operation, or indoor heat exchanger thermistor in heating operation)
Defective outdoor unit PCB
Defective indoor unit PCB
Troubleshooting
In case of “
P4
”
Replace the outdoor unit PCB.
P4
: Radiation fin thermistor
Caution
Be sure to turn off the power switch before connecting or disconnecting
connectors, or parts may be damaged.