5109
(U4)
HIC pipe temperature thermistor (TH2) open/short
Abnormal points and detection methods Causes and check points
Abnormal if TH2 detects to be open/short.
Open: –40°F [–40 ] or less
Short: 194°F [90 ] or more TH2: Thermistor <
HIC 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
The black square (■) indicates a switch position.
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 TH2.
Disconnect the connector to check the
resistance of TH2 using a tester.
Check a temperature of TH2.
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 TH2 can be displayed by
an operation of SW1 on the outdoor controller board.
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