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

Check code
Compressor temperature thermistor (TH4) open/short
5101
Abnormal points and detection methods
Abnormal if TH4 detects to be open/short.
(The open/short detection is disabled for 10 minutes after compressor
starts, during defrosting operation, or for 10 minutes after returning from
the defrosting operation.)
Open: 3 [37.4°F] or less
Short: 217 [422.6°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 TH4
Is there any abnormality such
as a disconnection, looseness or
breakage?
Disconnect the connector to check the
resistance of TH4 using a tester
Is the detected resistance normal?
Check a temperature of TH4.
Is the detected temperature normal?
OCH502C
TH4: Compressor 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 the connector in case of a
breakage.
Replace the thermistor.
The detected temperature of TH4 can be displayed
by an operation of SW1 on the 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)
58
Remedy