Abnormal points and detection methods Causes and check points
Abnormal if TH6 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°F [−40 ] or less
Short: 194°F [90 ] or more TH6: Thermistor <Suction pipe>
Disconnection or contact failure of connectors
Characteristic defect of thermistor
Defective outdoor multi controller circuit board
●Diagnosis of defectives
Make sure to turn the power OFF before connecting/disconnecting
any connectors, or replacing boards.
Diagnosis Remedy
Suction pipe temperature thermistor (TH6) open/short
The black square (■) indicates a switch position.
<Detected in outdoor unit>
5102
(U4)
No
Yes
Yes
Yes
No
No
Is there any abnormality such
as a disconnection, looseness or
breakage?
Is the detected resistance normal?
Is the detected temperature normal?
Connect the wiring/connector properly.
Replace it in case of a 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 TH6.
Disconnect the connector to check the
resistance of TH6 using a tester.
Check a temperature of TH6.
ON
OFF
1 2 3 4 5 6 7 8
SW1 Setting
Display on LED1,2
Unit
−99.9–999.9
°F
The detected temperature of TH6 can be displayed by
an operation of SW1 on the outdoor controller board.
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