LG ARUN Series Service Manual page 104

Troubleshooting Guide
Error
Error Type
No.
42*
Sensor error of low
Master 421
pressure
Slave 422
43*
Sensor error of high
Master 431
pressure
Slave 432
I Error diagnosis and countermeasure flow chart
Is sensor connected
to PCB correctly?
Yes
After replacement of
outdoor unit main PCB
is the system normal?
Yes
END
Low pressure sensor
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Only for training and service purposes
Error Point
Abnormal value of
sensor
(Open/Short)
Abnormal value of
sensor
(Open/Short)
No
Connect sensor to PCB correctly
No
Replace corresponding
pressure sensor
High pressure sensor
1. Bad connection of low pressure connector
2. Defect of low pressure connector (Open/Short)
3. Defect of outdoor PCB
1. Bad connection of high pressure connector
2. Defect of high pressure connector (Open/Short)
3. Defect of outdoor PCB
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Main Reasons
LGE Internal Use Only