LG THERMA V AHNW16606B0, Service Manual, Page: 41 / 81

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21 DC PEAK
(IPM Fault)
• Instant over current
• Over Rated current
• Poor insulation of IPM
• An instant over current in the U,V,W phase
- Comp lock
- The abnormal connection of U,V,W
• Over load condition
- Overcharging of refrigerant Pipe length.
Outdoor Fan is stop
• Poor insulation of compressor
Display
code
Title Cause of error Check point & Normal condition
Is installation
condition normal?
No
Yes
Yes
Recheck power and installation condition
1. Check Pipe clogging/distortion
2. Check Covering (Unit)
3. Check EEV connector assemble condition/normal
operation
4. Check refrigerant pressure
→
Reassemble or manage if abnormality found
1. Check resistance between each terminal of compressor
2. Check insulation resistance between compressor
terminal and pipe
→
Replace compressor if abnormality found
Are the resistance
Between each phase and
insulation resistance of Inverter
compressor normal?
No
Yes
1. Check inverter PCB assembly 1 U,V,W connector
connection condition
2. Check wire disconnection and wiring
3. Check compressor terminal connection condition
(bad contact)
→
Reassemble if abnormality found
Is compressor
Wire connection
condition normal?
No
Yes
Check inverter PCB assembly 1 IPM normality
→
Replace inverter PCB assembly 1
Is inverter PCB assembly 1 normal?
No
n
Error Diagnosis and Countermeasure Flow Chart
n
Comp checking method
V
U
W
Comp
Copper
pipe
Comp
WARNING
Before checking PCB(Inverter) or each outdoor electric parts, wait for 3 minutes after the power is off. When measuring at standby
state of power supply, after checking the measurement mode of the meter, be careful of the short-circuits with other parts.
Model Resistance(Ω) at 20°C
AHUW146A2
U-V 0.438(at 25˚C)
V-W 0.438(at 25˚C)
W-U 0.438(at 25˚C)
Terminal Insulation Resistance
U-panel ≥ 10MΩ
V-panel ≥ 10MΩ
W-panel ≥ 10MΩ