Heatsink Temperature Thermistor Open/Short - Mitsubishi PUMY-P60NKMU Technical & Service Manual

Check code
Heatsink temperature thermistor(TH8) open/short
5110
Abnormal points and detection methods
Abnormal if TH8 detects to be open/short.
P36/48 model
Open: -102 [215.6°F] or less
Short: 34.8 [-30.6°F] or more
P60 model
Open: 170.3 [338.5°F] or less
Short: 35.1 [-31.8°F] or more
●Diagnosis of defectives
Make sure to turn the power OFF before connecting/disconnecting
any connectors, or replacing boards.
Check the wiring and connector connection of TH8.
Is there any abnormality such
as a disconnection, looseness or
breakage?
Disconnect the connector to check the
resistance of TH8 using a tester.
Is the detected resistance normal?
Check a temperature of TH8.
Is the detected temperature normal?
OCH502C
TH8: Heatsink temperature thermistor
Diagnosis
Yes
No
No
Yes
No
Yes
Causes and check points
Disconnection or contact failure of connectors
Characteristic defect of thermistor
Defective outdoor controller board
The black square (■) indicates a switch position.
Connect the wiring/connector properly.
Replace it in case of a breakage.
Replace the thermistor.
The detected temperature of thermistor (TH8) The detected temperature of thermistor (TH8)
The detected temperature of TH8 can be displayed by
can be displayed by an operation of SW1 on the can be displayed by an operation of SW1 on the
an operation of SW1 on the outdoor controller board.
outdoor controller board. outdoor controller board.
SW1 Setting
Display on LED1,2 Unit
ON
-99.9 999.9 °F
OFF
1 2 3 4 5 6 7 8
Replace the controller board
(Malfunction of thermistor circuit).
No abnormality
( A connector contact failure is suspected).
63
Remedy