Check code
Abnormal points and detection methods
Causes and checkpoints
If TH3 detects to be open/short.
(The open/short detection is disabled during 10 seconds to 10 minutes.
after compressor starts, during defrosting operation, or for 10 minutes after
returning from the defrosting operation.)
Open: −40 [−40°F] or less
Short: 90 [194°F] or more TH3: Thermistor <Outdoor liquid pipe>
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
5105
(U4)
Outdoor liquid pipe temperature thermistor (TH3) open/short
The black square (■) indicates a switch position.
SW1 Setting
ON
OFF
Display on LED1, 2
Unit
−99.9–999.9
4
1 2
5 6 7 8
3
:
No
Yes
Yes
Yes
No
No
66
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 it 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 TH3.
Disconnect the connector to check the
resistance of TH3 using a tester.
Check the temperature of TH3.
The detected temperature of TH3 can be displayed by an
operation of SW1 on the outdoor controller board.
