Check code
Abnormal points and detection methods
Causes and checkpoints
If TH8 detects a temperature outside the specified range during
compressor operation.
TH8:
Thermistor <Heat sink>
1.
Blocked outdoor fan
2. Malfunction of outdoor fan motor
3. Blocked airflow path
4. Rise of ambient temperature
5. Characteristic defect of thermistor
6.
Malfunction of input circuit on outdoor power circuit board
7. Malfunction of outdoor fan driving circuit
●Diagnosis of defects
Make sure to turn the power OFF before connecting/disconnecting any connectors, or replacing boards.
Diagnosis
Remedy
Is 5110 displayed when restart?
4230
(U5)
Heat sink temperature trouble
No
Yes
No
No
Yes
Yes
No
No
Yes
Yes
Is 5110 displayed when restarted?
Does the fan rotate during
compressor operation?
Is there any obstacle which blocks
an airflow around the heat sink
?
Is there any abnormality such
as disconnection, looseness or
breakage?
Is the resistance normal?
Refer to the diagnosis of check code 5110.
Refer to the diagnosis of check code 4400.
Replace the thermistor
(Defective thermistor).
Replace the outdoor power circuit board
(Defective outdoor power circuit board).
Improve the airflow path.
Connect the wiring/connector properly.
Replace it in the case of breakage.
Check the wiring and connector connection TH8.
Check the resistance of TH8.
(air path blocked)
(no obstacle)
TH8 temp. - resistance characteristic
0°C
180 kΩ
25°C
50 kΩ
50°C
17 kΩ
70°C
8 kΩ
90°C
4 kΩ
68
69
OCH668G
