Check code
Abnormal points and detection methods
Causes and checkpoints
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 TH4: Thermistor <Compressor>
Disconnection or contact failure of connectors
Characteristic defect of thermistor
Defective outdoor multi controller circuit board
●Diagnosis of defects
Make sure to turn the power OFF before connecting/disconnecting
any connectors, or replacing boards.
Diagnosis
Remedy
5101
(U3)
Compressor temperature thermistor (TH4) open/short
The black square (■) indicates a switch position.
<Detected in outdoor unit>
No
Yes
Yes
Yes
No
No
64
OCH634C
Is there any abnormality such
as disconnection, looseness or
breakage?
Is the detected resistance normal?
Is the detected temperature normal?
Connect the wiring/connector properly.
Replace the connector in case of
breakage.
Replace the thermistor.
Replace the outdoor multi controller circuit
board (Malfunction of thermistor circuit).
No abnormality
( A connector contact failure is suspected).
Check the wiring and connector connection of TH4
Disconnect the connector to check the
resistance of TH4 using a tester.
Check the temperature of TH4.
The detected temperature of TH4 can be displayed
by an operation of SW1 on the outdoor controller
board.
SW1 Setting
ON
OFF
Display on LED1, 2
Unit
−99.9–999.9
:
4
1 2
5 6 7 8
3
