MXZ-SM48NAMHZ Service Manual

86
OCH789
Check code
5109
(U4)
HIC pipe temperature thermistor (TH2) open/short
Abnormal points and detection methods Causes and checkpoints
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 controller board
●Diagnosis of defects
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 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 controller 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 multimeter.
Check the temperature of TH2.
ON
OFF
1 2 3 4 5 6 7 8
SW1 Setting
Display on LED1,2 Unit
−99.9–999.9 ºF
The detected temperature of TH2 can be displayed by
an operation of SW1 on the outdoor controller board.