Mitsubishi MXZ-4C36NAHZ - Page 77

Check code
Abnormal points and detection methods Causes and check points
Abnormal if TH8 detects a temperature outside the specied range during
compressor operation.
TH8:
Thermistor <Heat sink>
Blocked outdoor fan
Malfunction of outdoor fan motor
Blocked airow path
Rise of ambient temperature
Characteristic defect of thermistor
Malfunction of input circuit on outdoor power board
Malfunction of outdoor fan driving circuit
●Diagnosis of defectives
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
32
-
F [0 ]·······180kΩ 77
-
F [25 ]····50kΩ
122
-
F [50
]····17kΩ 158
-
F [70 ]····8kΩ
194
-
F [90
]·······4kΩ
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 airow around the
heat
sink
?
Is there any abnormality such
as a 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 board
(Defective outdoor power board).
Improve the airow path.
Connect the wiring/connector properly.
Replace it in case of a breakage.
Check the wiring and connector connection TH8.
Check the resistance of TH8.
(air path blocked)
(no obstacle)
TH8 temp. - resistance characteristic
77
OCH573C