MXZ-SM48NAMHZ Service Manual

83
OCH789
Check code
Abnormal points and detection methods Causes and checkpoints
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 controller board
●Diagnosis of defects
Make sure to turn the power OFF before connecting/disconnecting
any connectors, or replacing boards.
Diagnosis Remedy
5102
(U4)
Suction pipe temperature thermistor (TH6) open/short
The black square (■) indicates a switch position.
<Detected in outdoor unit>
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 the 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 TH6.
Disconnect the connector to check the
resistance of TH6 using a multimeter.
Check the temperature of TH6.
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 TH6 can be displayed by
an operation of SW1 on the outdoor controller board.