098 099
_TROUBLE SHOOTING GUIDE BOOK _
- 115 -
Copyright ©2017 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
25*
Master
251
Slave1
252
Slave2
253
Slave3
254
Input Voltage high/low
Error
No.
Error Type Error Point Main Reasons
Input voltage is over limited
value of the product (304 V
or less, 536 V or more)
1.
Input voltage abnormal (T-N, R-S, S-T, T-R)
2. Outdoor unit Inverter PCB assembly dam-
age (input voltage sensing part)
3. N phase line disconnection
n
Error Diagnosis and Countermeasure Flow Chart
Yes
Recheck power and installation condition
Yes
Are there any power wire
connections normal?
No
Yes
1. Check R/S/T/N wiring conditions
→ Rewire them if abnormality found.
Is input voltage normal?
No
Check
R~S/S~T / T~R phase voltage is 380 V(-10 %) ~ 415 V(+ 10 %)
R~N/S~N/T~N phase voltage is 220 V(-10 %) ~ 240 V(+ 10%)
→ Check connection condition and wiring if power is
abnormal
Is Inverter PCB assembly
bridge diode joining condition normal?
No
Check bridge diode in IGBTM of Inverter PCB
Yes
Inverter PCB LED display error
No
Replace Inverter PCB assembly.
Error No. Error Type Error Point Main Reasons
25* Input Voltage high/low
Input voltage is over
limited value of the
product (304 V or less,
536 V or more)
1. Input voltage abnormal (T-N, R-S,
S-T, T-R)
2. Outdoor unit Inverter PCB assembly
damage(input voltage sensing part)
3. N phase line disconnection
- 114 -
Copyright ©2017 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
n
Error diagnosis and countermeasure flow chart
1. Defective high pressure switch
2. Defective fan of indoor unit or outdoor unit
3. Check valve of compressor clogged
4. Pipe distortion due to the pipe damage
5. Refrigerant overcharge
6.
Defective EEV at the indoor or outdoor unit.
7. Covering or clogging(Outdoor covering dur-
ing the cooling mode /Indoor unit filter clog-
ging during the heating mode)
8. SVC valve clogging
9. Defective outdoor PCB
10. Defective active path valve
Error
No.
Error Type Error Point Main Reasons
Compressor off due to the
high pressure switch in
outdoor unit
Excessive rise of discharge
pressure in outdoor com-
pressor
24*
Master
241
Slave1
242
Slave2
243
Slave3
244
Is high pressure switch
connector connected
to PCB?*
No
Note 1)
Note 2) Note 2)
Connect securely
Is high pressure switch
connector short
during off time?**
Yes
No
Is this error appeared
again after reset?
Yes
No
Is SVC valve open?
Yes
Re-check momentary
problem or not
Replace connecting cable
Open SVC valve
No
Yes
Is high pressure switch
terminal short?***
No
Replace high pressure switch
Yes
Is high pressure
more than 2500kPa
at manifold gauge?
No
Replace PCB
CH24 : inverter compressor PCB
CH109~154 : sub unit PCB
Yes
Is high pressure of
LGMV similar as
at manifold gauge?
No
Replace high pressure sensor
Yes
Check pipe is blocked or
not and take measure
Note 1) High pressure switch
connector on Main PCB
Note 2) Check short with high
pressure switch connector
Error No. Error Type Error Point Main Reasons
24*
Excessive rise of
discharge
pressure in outdoor
compressor
Compressor off due
to the high pressure
switch in outdoor
unit
1. Defective high pressure switch
2. Defective fan of indoor unit or outdoor unit
3. Check valve of compressor clogged
4. Pipe distortion due to the pipe damage
5. Refrigerant overcharge
6. Defective EEV at the indoor or outdoor unit.
7. Covering or clogging(Outdoor covering
during the cooling mode /Indoor unit filter
clogging during the heating mode)
8. SVC valve clogging
9. Defective outdoor PCB
10. Defective active path valve
Basic PartBasic PartBasic PartBasic Part
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