LG MULTI V M ARNU07GTU 4 Series Svc Manual page 69

Error
Error Type
No.
Excessive drop of
discharge pressure
351
of compressor
n Error diagnosis and countermeasure flow chart
Is service valve
opened?
Yes
Are communication cable/
piping normal?
Yes
Is amount of refrigerant
normal?
[refer refrigerant part]
Yes
Is fan normal?
(in heating outdoor fan,
in cooling indoor fan)
Yes
Is strainer Ok?*
Yes
Are the values of manifold
and low pressure sensor same?
( Is the low pressure value
actually low?)
Yes
Check indoor / outdoor unit EEV
Check Indoor unit PCB
Check indoor / outdoor unit
installation conditions
Error Point
Error happens
because of 3 times
successive
compressor off due to
excessive drop of low
pressure by the low
pressure sensor
Open service valve
No
check communication/
piping correction.
No
Is there pipe crack or trace
of refrigerant leakage?
Yes
Weld / reconnect the cracked
portion and recharge refrigerant
No
Check and replace related parts
No
Replace the strainer
No
Replace the pressure sensor
* If the temperature difference between inlet and outlet of strainer
is so large that frost or ice formation can be seen or confirmed
then clogging of strainer should be checked
(Notice: it is not full ice forming of strainer, in case that there is
not at inlet portion but at outlet portion)
- 69 -
Main Reasons
1. Defective low pressure sensor
2. Defective outdoor/indoor unit fan
3. Refrigerant shortage/leakage
4. Deformation because of damage of refrigerant pipe
5. Defective indoor / Compressor Module EEV
6. Covering / clogging
(Compressor Module covering during the cooling mode/
indoor unit filter clogging during heating mode)
7. SVC valve clogging
8. Defective Compressor Module PCB
9. Defective indoor unit pipe sensor
No
Adjust the amount of
refrigerant (Additive charge)
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only training and service purposes.
Troubleshooting Guide