LG LMNH122LRA0 Service Manual page 118

Troubleshooting Guide
5) Troubleshooting CH21
Display
Title
code
21
DC Peak
Comp
U
V W
Copper
Comp
pipe
Check Point
1. Check the wire connection. (U,V,W)
2. Check the load condition. (Refrigerant, Pipe length, ...)
3. Check the electricity leakage of the compressor.
4. Check the resistance of compressor.
5. Check the insulation from water at IPM part.
6. Check the IPM circuit.
118 Multi type Air Conditioner
Cause of error
• Instant over current
• Over Rated current
• Poor insulation of IPM
Resistance(Ω) at 20°C
Terminal
Ω
U-V
V-W
W-U
Resistance(Ω) at 20°C
Terminal
Ω U-GND
V-GND
W-GND
Normal : Over 2MΩ.
Normal : 0.8Ω(Cons.)
Check the trace of water.
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.
• Poor insulation of compressor
Constant comp.
0.8
0.8
0.8
Constant comp.
2MΩ
2MΩ
2MΩ
Adjust the load condition
No difference at each terminal.