LG Electronics General Wall Mounted-Inverter Type Troubleshooting CH21, Copper Comp pipe

Part 4	Trouble Shooting
3) Troubleshooting CH21
Error	Title	Cause of error	Check point & Normal condition
code
			• An instant over current in the U,V,W phase
		• Instant over current	- Comp lock
21			- The abnormal connection of U,V,W
	DC Peak	• Over Rated current	• Over load condition
		• Poor insulation of IPM	- Overcharging of refrigerant
			- Pipe length.
			• Poor insulation of compressor

	Comp
	U
	Ω
V	W

Copper

Comp pipe

Ω

Resistance(Ω) at 20°C(68°F)

Terminal	Inverter	Constant
	comp.	comp.
U-V	0.64	0.8
V-W	0.64	0.8
W-U	0.64	0.8
Resistance(Ω) at 20°C(68°F)
Terminal	Inverter	Constant
	comp.	comp.
U-GND	2MΩ	2MΩ
V-GND	2MΩ	2MΩ
W-GND	2MΩ	2MΩ

Check Point

1.Check the wire connection. (U,V,W)

2.Check the load condition. (Refrigerant, Pipe length, …) → Adjust the load condition

3.Check the electricity leakage of the compressor. → Normal : Over 2MΩ.

4.Check the resistance of compressor. → Normal : 0.65Ω(INV), 0.8Ω(Cons.) → No difference at each terminal.

5.Check the insulation from water at IPM part. → Check the trace of water.

6.Check the IPM circuit.

58Room Air Conditioner