LG Multi-Inverter Service Manual page 107

4. Trouble Shooting
Display
Title
code
DC PEAK
21 (IPM Fault)
I Error Diagnosis and Countermeasure Flow Chart
Is installation
condition normal?
Yes
Are the resistance
Between each phase and
insulation resistance of Inverter
compressor normal?
Yes
Is compressor
Wire connection
condition normal?
Yes
Is inverter PCB assembly normal?
Yes
Recheck power and installation condition
I Comp checking method
Comp
U
Ω
V W
Copper
Comp
pipe
Ω
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Only for training and service purposes
Cause of error
• Instant over current
• Over Rated current
• Poor insulation of IPM
1. Check Pipe clogging/distortion
2. Check Covering (Indoor/Outdoor Unit)
3. Check EEV connector assemble condition/normal
No
operation
4. Check refrigerant pressure
Reassemble or manage if abnormality found
1. Check resistance between each terminal of compressor
(1.083~1.123Ω ±5%)
No
2. Check insulation resistance between compressor
terminal and pipe (over 50M )
Replace compressor if abnormality found
1. Check inverter PCB assembly U,V,W connector
connection condition
2. Check wire disconnection and wiring
No
3. Check compressor terminal connection condition
(bad contact)
Reassemble if abnormality found
Check inverter PCB assembly IPM normality
No
Replace inverter PCB assembly
Resistance(Ω) at 20°C
Inverter
Terminal
comp.
U-V 1.083
V-W 1.123
W-U 1.096
Resistance(Ω) at 20°C
Inverter
Terminal
comp.
U-GND 50MΩ
V-GND 50MΩ
50MΩ
W-GND
- 106 -
Check point & Normal condition
• 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
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