Troubleshooting Guide
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Error diagnosis and countermeasure flow chart
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
Error
No.
Error Type
Error Point
Main Reasons
Error happens
because of 3 times
successive
compressor off due to
excessive drop of low
pressure by the low
pressure sensor
Excessive drop of
discharge pressure
of compressor
351
Is service valve
opened?
Open service valve
Are communication cable/
piping normal?
Yes
No
Is amount of refrigerant
normal?
[refer refrigerant part]
Yes
No
Is fan normal?
(in heating outdoor fan,
in cooling indoor fan)
Yes
Adjust the amount of
refrigerant (Additive charge)
check communication/
piping correction.
Check and replace related parts
Is strainer Ok?*
No
Replace the strainer
No
Replace the pressure sensor
Yes
Yes
Check indoor / outdoor unit EEV
Check Indoor unit PCB
Check indoor / outdoor unit
installation conditions
Yes
Are the values of manifold
and low pressure sensor same?
( Is the low pressure value
actually low?)
No
Is there pipe crack or trace
of refrigerant leakage?
Weld / reconnect the cracked
portion and recharge refrigerant
No
Yes
* 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)
